Trichology  is the study of the  hair  and  scalp . [ 1 ]  The term derives from  Ancient Greek  θρίξ ( thríx ), "hair" [ 2 ]   and -λογία  -logia . In most jurisdictions the title of a  trichologist , not the field of trichology, is considered a para-medical discipline. [ 1 ]


The Institute of Trichologists was founded in 1902. [ 3 ]   [ 4 ]  The first journal for the field,  International Journal of Trichology , was founded in 2009. [ 5 ]


Trichology includes subspecialties that deal either with certain diseases or diseases of certain parts of the hair. Some of them are:


Hair analysis  may refer to the chemical analysis of a  hair  sample, but can also refer to microscopic analysis or comparison.  Chemical hair analysis may be considered for retrospective purposes when blood and urine are no longer expected to contain a particular contaminant, typically three months or less.


Its most widely accepted use is in the fields of  forensic toxicology , in  pre-employment drug testing  and, increasingly, in environmental  toxicology . [ 1 ] [ 2 ]   Several  alternative medicine  fields also use various  hair analyses  for environmental  toxicology , but these uses are controversial, evolving, and not standardized.


Microscopic hair analysis has traditionally been used in forensics as well.  Analysts examine a number of different characteristics of hairs under a microscope, usually comparing hair taken from a crime scene and hair taken from a suspect.  It is still acknowledged as a useful technique for confirming that hairs do not match. But DNA testing of evidence has overturned many convictions that relied on hair analysis. Since 2012, the Department of Justice has conducted a study of cases in which hair analysis testimony was given by its agents, and found that a high proportion of testimony could not be supported by the state of science of hair analysis. [ citation needed ]


Chemical hair analysis is used for the detection of many therapeutic drugs and  recreational drugs , including  cocaine ,  heroin ,  benzodiazepines  and  amphetamines . [ 3 ] [ 4 ]   Hair analysis is less invasive than a blood test, if not quite as universally applicable.  In this context, it has been reliably used to determine compliance with therapeutic drug regimes or to check the accuracy of a witness statement that an illicit drug has not been taken.  Hair testing is an increasingly common method of assessment in substance misuse, particularly in legal proceedings, or in any situation where a subject may have decided not to tell the entire truth about his or her substance-using history.  Post-mortem hair sample analysis can also be performed, to allow for determination of long-term drug use or poisoning. [ 5 ]  It is also used by employers, who test their employees. [ 6 ]


Hair analysis has the virtue of showing a 'history' of drug use due to hair's slow growth.   Urine analysis  might detect drugs taken in the past 2–3 days; hair analysis can sometimes detect use as far as 90 days, although certain cosmetic treatments (e.g. dyeing hair) can interfere with this. [ 7 ] [ 8 ]
Notably,  basic  drugs get incorporated into hair to a greater extent than neutral or  acidic  drugs, e.g.  amphetamines  and  cocaine
are present in higher concentrations in hair compared with
benzodiazepines and cannabinoids. [ 9 ]


Large-scale drug screening (or urine, hair and other samples) is usually done using enzyme-linked immunosorbent assays ( ELISA ). [ 10 ]  Positive ELISA findings are followed by confirmatory testing with  liquid chromatography–mass spectrometry  (LC-MS) or  gas chromatography–mass spectrometry  (GC-MS). [ 8 ]  Chromato-mass-spectrometry is less likely to result in false positive findings than ELISA, but the former requires expensive equipment and highly trained personnel.


The judicial admissibility of the test in the United States is guided by the  Daubert standard .  A notable court case was  United States v. Medina, 749 F.Supp. 59 (E.D.N.Y.1990) . [ 11 ] [ 12 ]


Microscopic hair analysis consists of the comparison of several strands of hair under a microscope and determining if the physical characteristics of each individual hairs are consistent with each other or not. It was accepted as a forensic science by the 1950s. [ 13 ]   Researchers often monitored more than a dozen attributes, including pigment distribution and scale patterns.  This technique has been used in criminal investigations to try to tie hair found at a crime scene, or other location of note, and confirm if the hair matches that of a suspect.  While a simple hair color match might be  consistent  with a certain suspect having been at the scene – black hair at the scene when the suspect has black hair – microscopic hair analysis began to claim a stronger standard by the 1970s. Rather than merely "narrow the field" of possibilities, hair analysts claimed to be able to match a specific person, such that the hair could be 'proof' of a specific suspect's presence.  While the typed reports often hedged the certainty of microscopic hair analysis, witnesses in court would not always be as modest. The manager of the Montana state crime lab testified there was a "1 in 10,000 chance" that hairs found at a crime scene did not come from the suspect in one case, for example. [ 14 ]


Microscopic hair analysis has a long tradition of being used in crime fiction as well; it was originally popularized in the  Sherlock Holmes  series before being widely used by the police. [ 13 ]   Fictional TV programs involving police procedurals and detectives have continued to use it since, including  Columbo ,  Quincy, ME ,  Dexter , and  CSI . [ 14 ]


Skepticism about the stronger claims used by witnesses in the 1970s and 1980s existed at the time. Researchers said in 1974 that the whole process was inherently subjective, and the FBI wrote in 1984 that hair analysis cannot positively match one single person. [ 13 ]  In the 1990s,  DNA profiling  was introduced as a key new technique into forensics investigations; it introduced a new level of certainty about matching suspects to evidence. DNA analysis of old cases from the 1970s and 80s, however, contradicted conclusions about a number of earlier matches on the basis of hair analysis. [ 15 ]


In 1994, the Justice Department created a task force which would eventually review 6,000 cases by 2004, focusing on the work of one particularly zealous examiner, Michael Malone. [ 13 ]  These reviews came after reports that sloppy work by examiners at the FBI lab was producing unreliable forensic evidence in court trials.  At first, these investigations were largely kept quiet;  The Washington Post  reported that "Instead of releasing those findings, they made them available only to the prosecutors in the affected cases." [ 13 ]   A study of FBI Laboratory hair analysis cases between 1996 and 2000 was released in 2002 by Max M. Houck and Bruce Budowle. [ 16 ]   The study showed that 11% of hair analysis "matches" were contradicted by DNA analysis.  As the set of cases analyzed was one which would be expected to favor matches strongly in any case – only hair of individuals the police already believed to be potential suspects was sent in – this error rate was considered to be extremely high. [ 13 ]


Kirk L. Odom  was convicted of rape in Washington, DC in 1982 by no physical evidence except microscopic hair analysis performed by the  FBI Crime Laboratory . [ 13 ]  Combined with a witness's identification in a  line-up  (another technique which modern research has shown to be much less reliable than previously thought), Odom was sentenced to twenty or more years in jail. DNA analysis, however, proved that Odom was entirely innocent. [ 14 ]   While Odom had been released from prison in 2003, he was officially exonerated in 2012 and was paid a large settlement by the city. [ 17 ]


In a similar case,  Santae Tribble  was convicted in 1979 at the age of 17 in Washington, DC of murder due to FBI testimony in a hair analysis match of hair found at the scene. But he had three witnesses who gave him an  alibi  for the time when the crime was committed.  The prosecutor overstated the reliability of hair analysis in identifying a single person, saying in his closing statement that "There is one chance, perhaps for all we know, in 10 million that it could [be] someone else's hair." [ 13 ]   DNA testing in January 2012, however, showed that the prosecution's key piece of evidence, the hair, did not in fact match the defendant. Tribble was fully exonerated in December 2012, having served 28 years in prison that resulted in severe health problems. [ 18 ]


The outcry from defense attorneys about the unreliability of hair analysis and overstatement by FBI experts has resulted in the FBI conducting a review of disputed hair analysis matches since 2012.  Due to what it found, in July 2013 the Justice department began an "unprecedented" review of older cases involving hair analysis, examining more than 21,000 cases referred to the FBI Lab's hair unit from 1982 through 1999.


By 2015, these cases included as many as 32 death penalty convictions, in which FBI experts may have exaggerated the reliability of hair analysis in their testimony and affected the verdict. Of these, 14 persons have been executed or died in prison. [ 19 ] [ 20 ]  In 2015, DOJ released findings on 268 trials examined so far in which hair analysis was used (the review was still in progress). The review concluded that in 257 of these 268 trials (95 percent), the analysts gave flawed testimony in court that overstated the accuracy of the findings in favor of the prosecution.  About 1200 cases remain to be examined. The department emphasized its commitment to following up on these cases to correct any wrongs, saying that they "are committed to ensuring that affected defendants are notified of past errors and that justice is done in every instance. The department and the FBI are also committed to ensuring the accuracy of future hair analysis, as well as the application of all disciplines of forensic science." [ 19 ]


In 2017, new Attorney General  Jeff Sessions , appointed by President  Donald Trump , announced that this investigation would be suspended, at the same time that he announced the end of a forensic science commission that had been working to establish standards on several tests and to improve accuracy; it was a "partnership with independent scientists to raise forensic science standards". [ 21 ]  Independent scientists, prosecutors, defense counsel and judges criticized ending the commission, saying that the criminal justice system needed to rely on the best science.


As of late 2019, 75 people who were convicted of a crime based on microscopic hair comparison were subsequently exonerated. [ 22 ]   Another notable case that received media attention since was  Anthony Broadwater , who had been convicted of raping  Alice Sebold  in 1982, and was formally exonerated in 2021 after finishing his time in 1998.  The only physical evidence the prosecution offered in 1982 was a hair analysis that was "consistent" with Broadwater.  More alarmingly, the only reason the case was re-examined was the unusual fact that Sebold had written an extensive memoir of her experiences ( Lucky ), which allowed later investigators to uncover major problems with the case. [ 23 ]


Analysis of hair samples has many advantages as a preliminary screening method for the presence of toxic substances deleterious to health after exposures in air, dust, sediment, soil and water, food and toxins in the environment.  The advantages of hair analysis include the non-invasiveness, low cost, and the ability to measure a large number of, potentially interacting, toxic and biologically essential elements.  Hence, head hair analysis is increasingly being used as a preliminary test to see whether individuals have absorbed poisons linked to behavioral or health problems. [ 1 ]


The use of hair analysis appears to be valid for the measurement of lifelong, or long-term heavy metal burden, if not the measurement of general elemental analysis. Several studies, including the analysis of  Ludwig van Beethoven 's hair, have been conducted in conjunction with the  National Institutes of Health  and  Centers for Disease Control and Prevention . [ citation needed ]


In a 1999 study on hair concentrations of  calcium ,  iron , and  zinc  in pregnant women and effects of supplementation, it was concluded that "From the analyses, it was clear that hair concentrations of Ca, Fe, and Zn could reflect the effects of supplementation... Finally, it could be concluded that mineral element deficiencies might be convalesced by adequate compensations of mineral element nutrients." [ 24 ]


Hair analysis has been used in occupational, [ 25 ]   environmental  and some branches of  alternative medicine  as a method of investigation to assist screening and/or  diagnosis . The hair is sampled, processed and analyzed, studying the levels of mineral and metals in the hair sample. Using the results, as part of a proper examination or test protocol, [ 26 ]  practitioners screen for toxic exposure and  heavy metal poisoning . Some advocates claim that they can also diagnose  mineral   deficiencies  and that people with  autism  have unusual hair mineral contents. [ 27 ]  These uses are often controversial, and the American Medical Association states, "The AMA opposes chemical analysis of the hair as a determinant of the need for medical therapy and supports informing the American public and appropriate governmental agencies of this unproven practice and its potential for health care fraud." [ 28 ]
A recent review of scientific literature by Dr Kempson highlighted analysis of metals/minerals in hair can be applied in large population studies for researching epidemiology and groups of chronically exposed populations, however any attempt to provide a diagnosis based on hair for an individual is not possible. [ 29 ]  An exception to this can be in advanced analyses for acute poisoning. [ 30 ]


Hair multiplication , or  hair cloning , is a proposed technique to counter hair loss. The technology is in its early stages, but multiple groups have demonstrated pieces of the technology at a small scale, with a few in commercial development.


Scientists previously assumed that in the case of complete baldness,  follicles  are completely absent from the scalp, so they cannot be regenerated. However, the follicles are not entirely absent, as there are stem cells in the bald scalp from which the follicles naturally arise. The behavior of these follicles is suggested to be the result of  progenitor cell  deficiency in these areas.


The basic idea of hair  cloning  is that healthy follicle cells or  dermal papillae  can be extracted from the subject from areas that are not bald and are not suffering hair loss. They can be multiplied (cloned) by various culturing methods [ 1 ]  and the new cells can be injected back into the bald scalp, where they would produce healthy hair.


One of the first companies to begin experimenting with hair cloning was Intercytex. [ 2 ]  Intercytex tried to clone new hair follicles from the stem cells harvested from the back of the neck. They hoped that if they multiplied the follicles and then implanted them back in the scalp in the bald areas, they would be successful in regrowing the hair itself. [ 3 ]  In 2008, Intercytex interpreted that they failed in fully developing the hair cloning therapy and decided to discontinue all research. [ 3 ]


The first time scientists were able to grow artificial hair follicles from stem cells was in 2010. Scientists at the  Technische Universität Berlin  in Germany, with Intercytex and several other research teams, took animal cells and created follicles by using them. As a result, they produced follicles "thinner than normal". They were able to clone one or two follicles from an extracted hair.


Aderans Research Institute, a Japanese company, worked on what they called the "Ji Gami" process, which involved the removal of a small strip of the scalp, which is broken down into individual follicular stem cells. After the extraction, these cells are cultured and injected back into the bald areas of the scalp. [ citation needed ]  The trials continued in 2012. Aderans decided to discontinue the funding of its hair multiplication research in July 2013. [ 4 ] [ better source needed ]


In 2012, scientists from the University of Pennsylvania School of Medicine published their own findings regarding hair cloning. [ 5 ]  During their investigation, they found that non-bald and bald scalps have the same number of stem cells, but the  progenitor cell  number was significantly depleted in the case of the latter. Based on this, they concluded that it is not the absence of the stem cells that are responsible for hair loss but the unsuccessful activation of said cells. [ 6 ]


In 2015, initial trials for human hair were successful in generating new follicles, [ 7 ]  but the hairs grew in varying directions.


In 2016, scientists in Japan announced they had successfully grown human skin in a lab. [ 8 ]  The skin was created using  induced pluripotent stem cells , and when implanted in a mouse, the skin grew hairs successfully. The group has formed partnerships with Organ Technologies and  Kyocera Corporation  to commercially develop the research. [ 9 ]


dNovo Bio, a  Silicon Valley –based company, was founded in 2018 and has demonstrated growing a patch of human hair on a mouse. [ 10 ] [ better source needed ]  In July 2019, a researcher from San Diego–based Stemson Therapeutics, partnered with  UCSD , successfully grew his own follicles on a mouse using  iPSC -derived  epithelial  and dermal cell therapy. The hair was aligned properly with a 3D-printed biodegradable shaft. The hairs were permanent and regenerated naturally. [ 11 ]  Stemson intends to enter clinical trials in 2026. [ 12 ]


In October 2022, researchers from the Japan-based Yokohama National University successfully cloned fully-grown mouse hair follicles for the first time in history. [ 13 ]


The  Hamilton–Norwood scale  is used to  classify  the stages of  male pattern baldness . It is one of the widely accepted and reproducible classification system for the male pattern hair loss (androgenetic alopecia). The stages are described with a number from 1 to 7 with a type A variant for the cases with anterior involvement. [ 1 ]


Androgenetic alopecia follows a defined pattern of hair loss, beginning with bitemporal recession of the frontal hairline. Eventually, diffuse thinning over the vertex (top) of the scalp occurs. With progression, complete hair loss in this region is common. The bald patch progressively enlarges and eventually joins the receding frontal hairline.


This  measurement  scale was first introduced by James Hamilton in the 1950s and later revised and updated by O'Tar Norwood in the 1970s. [ 2 ]  It is sometimes referred to as the  Norwood–Hamilton scale  or simply the  Norwood scale .


The scale is regularly used by doctors to assess the severity of baldness, but it is not considered very reliable since examiners' conclusions can vary. [ 1 ]


Dermatologists might use the Norwood Scale on patients to assess male pattern baldness. It is especially used to check if hair loss treatments are helping patients regaining hair.


This  dermatology  article is a  stub . You can help Wikipedia by  expanding it .


The  International Journal of Trichology  is a biannual  peer-reviewed   open access   medical journal  published by  Medknow Publications  on behalf of the  Hair Research Society of India . The journal publishes articles on the subject of  trichology  including forensic trichology. The  editor-in-chief  is Patrick Yesudian.


The journal is abstracted and indexed in  Scopus ,  EBSCO databases , and  Expanded Academic ASAP .


This article about a  medical journal  is a  stub . You can help Wikipedia by  expanding it .


See tips for writing articles about academic journals . Further suggestions might be found on the article's  talk page .


The  Ludwig scale  is a method of classifying  female pattern baldness  (androgenic alopecia), and ranges from stages I to III. [ 1 ]


Stage I begins with thinning on the top of the head. In stage II the scalp starts to show. All of the hair at the crown of the head may be lost when the hair loss progresses to stage III. However, the scale is used merely for general categorization. Many women do not actually fit into the Ludwig stages.


Blepharoplasty  ( Greek :  blepharon , "eyelid" +  plassein  "to form") is the  plastic surgery  operation for correcting defects, deformities, and disfigurations of the  eyelids ; and for aesthetically modifying the eye region of the face. With the excision and the removal, or the repositioning (or both) of excess tissues, such as  skin  and  adipocyte fat , and the reinforcement of the corresponding  muscle  and  tendon  tissues, the blepharoplasty procedure resolves functional and cosmetic problems of the  periorbita , which is the area from the eyebrow to the upper portion of the cheek. The procedure is more common among women, who accounted for approximately 85% of blepharoplasty procedures in 2014 in the US and 88% of such procedures in the UK. [ 1 ] [ 2 ]


The operative goals of a blepharoplastic procedure are the restoration of the correct functioning to the affected eyelid(s) and the restoration of the aesthetics of the eye-region of the face, which are achieved by eliminating excess skin from the eyelid(s), smoothing the underlying eye muscles, tightening the supporting structures, and resecting and re-draping the excess fat of the retroseptal area of the eye, in order to produce a smooth anatomic transition from the lower eyelid to the cheek.


In an eye surgery procedure, the usual correction or modification (or both) is of the upper and the lower eyelids, and of the surrounding tissues of the eyebrows, the upper nasal-bridge area, and the upper portions of the cheeks, which are achieved by modifying the  periosteal coverings  of the facial bones that form the  orbit  (eye socket). The periosteum comprises two-layer connective tissues that cover the bones of the human body:


The  East Asian blepharoplasty  procedure differs from the classic blepharoplasty. In younger patients, the goal of the surgery is to create a supratarsal fold ("double eyelid surgery") whereas in older patients the goals are to create or elevate the supratarsal fold and to resect surplus eyelid skin ("Asian blepharoplasty"). [ 3 ] [ 4 ]


The thorough pre-operative  medical  and surgical histories, and the physical examination of the patient's  periorbital area  (eyebrow-to-cheek-to-nose), determine if the patient can safely undergo a blepharoplasty procedure to feasibly resolve (correct or modify, or both) the functional and aesthetic indications presented by the patient. Sequentially, lower eyelid blepharoplasty can successfully address the anatomic matters of excess eyelid skin, slackness of the eye-muscles and of the  orbital septum  (palpebral ligament), excess orbital fat, malposition of the lower eyelid, and prominence of the nasojugal groove, where the orbit (eye socket) meets the slope of the nose. [ 5 ]


Concerning the upper eyelid, a blepharoplasty procedure can resolve the loss of  peripheral vision , caused by the slackness of the upper-eyelid skin draping over the eyelashes; the outer and the upper portions of the field of vision of the patient are affected and cause him or her difficulty in performing mundane activities such as driving an automobile and reading a book. [ 6 ]


In many East Asian countries, double eyelid surgery is the most popular surgery, especially in South Korea. Depending on the methods, directing doctors' experience, and the difficulty of the individual case, this surgery can cost between about  US$ 2,000 to $4,000. The procedure is famous for producing double-eyelid for patients for the long-term. [ citation needed ]  This kind of operation normally takes about 30 minutes to an hour, and patients are not required to stay hospitalized afterward. Stitches are removed 5 to 7 days after surgery. Many foreigners go to South Korea each year for blepharoplasty. [ 7 ]


A blepharoplasty procedure usually is performed through external surgical incisions made along the natural skin lines (creases) of the upper and the lower eyelids, which then hide the surgical  scars  from view, especially when affected by the skin creases below the  eyelashes  of the lower eyelid. The incisions can also be made from the  conjunctiva , the interior surface of the lower eyelid, as in the case of a transconjunctival blepharoplasty. [ 9 ]


Transconjunctival lower blepharoplasty technique was pioneered by Clinical Professor of Surgery at the University of Chicago Medicine, [ 10 ]  Dr. Anthony J. Geroulis [ 11 ]  and introduced to medical trial in 1998. Transconjunctival Technique has become the norm in the plastic surgery field with most surgeons preferring it over the external surgical incisions. This technique is particularly useful for patients with darker skin tones where standard external incision often leaves a visible white scar.


Transconjunctival blepharoplasty technique permits the excision (cutting and removal) of the lower-eyelid  adipose tissue  without leaving a visible scar, but the technique does not allow the removal of excess eyelid-skin. [ 6 ]


A blepharoplasty operation usually requires 1–3 hours to complete. Post-operatively, swelling and bruising is expected and will usually resolve without further intervention; application of cold compresses can help to reduce the duration and discomfort. [ 12 ]  There are no standardized outcome measures for upper or lower blepharoplasty. [ 12 ]  Blepharoplasty is generally a relatively safe surgery, but possible complications include hematoma/ecchymosis, lagophthalmos (incomplete or abnormal closure of the eyelids), ptosis (drooping of the upper eyelid), scarring, dry eyes, orbital hematoma/compartment syndrome, lymphedema, and ocular motility disorders. [ 13 ]


After the procedure, a type of stitch known as a canthopexy is placed near the outer corner of the lower eyelid, which is inside the tissue. This allows the eyelid's position to remain fixed during the healing process. The canthopexy is dissolved after four to six weeks of use. For particular patients, a mid-face elevation may be required to rejuvenate the lower eyelid-cheek complex. [ 14 ] [ unreliable source? ]


The anatomic condition of the eyelids, the "wear-and-tear" quality of the patient's skin, age, and the general condition of the adjacent tissues affect the functional and aesthetic results achieved. Additional to the anatomic conditions of the eye region of the patient, the possible occurrence of  medical complications  is determined by factors including: [ medical citation needed ]


As techniques began developing the ancient Greeks and Romans began writing down and collecting everything they knew involving these procedures.  Aulus Cornelius Celsus , a first-century Roman, described making an excision in the skin to relax the eyelids in his book  De Medicina . [ 15 ]


Karl Ferdinand von Gräfe  coined the phrase blepharoplasty in 1818 when the technique was used for repairing deformities caused by cancer in the eyelids. [ 16 ] [ 17 ]


Laser blepharoplasty is the performance of eyelid  surgery using a laser  instead of a scalpel. Laser blepharoplasty is often combined with laser eyelid rejuvenation, as the two procedures can be performed in conjunction.


A  CO 2  laser  blepharoplasty offers many benefits over a blepharoplasty performed using a scalpel. Some of these benefits include less bleeding, shortened surgical time, better intraoperative visibility, less bruising and swelling, less pain or discomfort, and smoother healing. [ 18 ]


Historically there has been some contention as to the categorization of laser treatment on upper or lower eyelids as blepharoplasty, which is itself by definition surgical. The statutory definition of surgery and that supported by the American College of Surgeons states that surgery is the "treatment ... by any instrument causing localized alteration or transportation of live human tissue, which include lasers...". [ 19 ]


Comedo extraction  is a widely used method of treatment for  acne vulgaris . [ 1 ]  A  dermatologist  or cosmetologist may extract  blackheads  (open comedones) using gentle pressure around the pore opening, and  whiteheads  (closed comedones) by incision with a large needle or a blade. [ 2 ]


If performed skillfully, this treatment may be beneficial to the patient. [ 2 ]  Possible negative effects of the procedure include incomplete extraction, refilling, scarring and tissue damage. [ 2 ]  There are few articles describing the use of comedo extraction in peer-reviewed dermatology journals. [ 1 ] [ needs update ]  In one 1964 study of extraction of non-inflamed whiteheads on patients' foreheads (the only study of the procedure cited in a 2007  literature review ), the procedure reduced the number of future inflamed lesions and the recurrence rate of comedones, but worsened patients' inflamed cystic lesions. [ 3 ]


Complete circumferential peripheral and deep margin assessment  ( CCPDMA ) is the preferred method for the removal of certain  cancers , especially  skin cancers . [ 1 ] [ 2 ]


There are two forms of CCPDMA surgery:  Mohs surgery  and surgical excision coupled with margin assessment. Other examples of CCPDMA are found in classical  pathology  textbooks as techniques of cutting surgical specimens to allow the examination of the inferior and lateral margins of typically elliptical surgical specimens.


CCPDMA is superior to standard  bread loafing  due to very low  false negative  error rate.  Bread loafing extrapolates the margin exam of a few representative slides to the entire  surgical margin . CCPDMA allows for the complete examination of the surgical margin without statistical extrapolation and assumptions. [ citation needed ]


The first advantage of CCPDMA method is that it allows for the complete examination of the entire surgical margin of the specimen.  The second advantage of CCPDMA is allowing the  surgeon  to remove only a very small surgical margin.  As the CCPDMA surgery is frequently performed using  frozen section  pathology, immediate reporting of positive surgical margin is made, and the tumor can be completely removed in the same day. Traditional pathology processing is called "bread loafing", and only allows for the partial examination of the surgical margin.  Some surgeons send the specimen out for processing, and the result of the surgical margin assessment may not be made until days later. [ 3 ]


CCPDMA is subject to the basic principles of histology sectioning. From a physical standpoint, the true margin is never assessed because a thin face margin has to be cut through in order to make the slide for examination.  Therefore, a true and complete assessment of all margins is never achieved. Serial sectioning allows CCPDMA approaches near-complete evaluation of the surgical margin and may be performed by pathologists, dermatologists, and surgeons. [ citation needed ]


Dermabrasion  is a type of surgical skin planing, generally with the goal of removing  acne , scarring and other skin or tissue irregularities, typically performed in a professional medical setting by a  dermatologist  or  plastic surgeon  trained specifically in this procedure. Dermabrasion has been practiced for many years (before the advent of lasers) and involves the controlled deeper  abrasion  (wearing away) of the upper to mid layers of the  skin  with any variety of strong abrasive devices including a wire brush, diamond wheel or fraise, sterilized sandpaper, salt crystals or other mechanical means.


Dermabrasion procedures are surgical, invasive procedures that typically require a  local anaesthetic . Often, they are performed in surgical suites or in professional medical centers. Since the procedure can typically remove the top to deeper layers of the epidermis and extend into the  reticular dermis , there is always minor skin bleeding. The procedure carries risks of scarring, skin discoloration, infections and facial herpes virus ( cold sore ) reactivation. In aggressive dermabrasion cases, there is often tremendous skin bleeding and spray during the procedure that has to be controlled with pressure. Afterward, the skin is normally very red and raw-looking. Depending on the level of skin removal with dermabrasion, it takes an average of 7–30 days for the skin to fully heal ( re-epithelialize ). Often, the procedure is performed for deeper acne scarring and deep surgical scars. Dermabrasion is currently rarely practiced and there are very few doctors who are trained and still perform this surgery. Dermabrasion has largely been replaced by technologies including lasers,  CO 2  or  Erbium:YAG   laser . Laser technologies carry the advantage of little to no bleeding and are often less operator dependent than dermabrasion.


The purpose of surgical dermabrasion is to help diminish the appearance of deeper scars and skin imperfections. Often, the goal is to smooth the skin and, in the process, remove small scars (as from acne), uneven skin tone from scars or  birthmarks , sun damage,  tattoos , age spots,  Stretch marks   [ citation needed ]  or fine  wrinkles . [ 1 ]


Dermabrasion is a mechanical surgical skin planing method which has remained popular partially because it may afford an overall lower cost and may provide similar or superior results as newer laser methods for certain skin conditions. [ 2 ]


Microdermabrasion is a light cosmetic procedure that uses a mechanical medium for  exfoliation  to remove the outermost layer of dead  skin cells  from the  epidermis . Most commonly, microdermabrasion uses two parts: an exfoliating material such as crystals or diamond flakes, and a machine-based suction to gently lift up the skin during exfoliation. It is a non-invasive procedure and may be performed in-office by a trained  skin care  professional. [ 3 ]  It may also be performed at home using a variety of products which are designed to mechanically exfoliate the skin. Many salon machines and home-use machines use adjustable  suction  to improve the efficacy of the abrasion tool.


Microdermabrasion is considered a relatively simple, easy, painless and non-invasive skin rejuvenation procedure. Typically there are no needles or anesthetics required for microdermabrasion. The vacuum pressure and speed are adjusted depending on the sensitivity and tolerance of the skin. [ citation needed ]  Microdermabrasion is often compared to the feeling of a cat licking the skin - a rough but gentle texture.  Typical microdermabrasion sessions can last anywhere from 5 to 60 minutes. Minimal to no recovery time is required after microdermabrasion and most people immediately return to daily activity after a session. Makeup and non-irritating creams can usually be applied within a few hours or right after microdermabrasion. Since there is an often immediate increased minor skin sensitivity after microdermabrasion, irritating products such as  glycolic acids ,  Alpha Hydroxy Acids ,  Retinoid  products or fragranced creams and lotions are typically avoided right after the procedure. [ citation needed ]


Traditionally, a "crystal" microdermabrasion system includes a pump, a connecting tube, a hand piece, and a vacuum. While the pump creates a high-pressure stream of inert crystals (aluminum oxide, magnesium oxide, sodium chloride, or sodium bicarbonate) to abrade the skin, the vacuum removes the crystals and exfoliated skin cells. Alternatively, the inert crystals can be replaced by a roughened surface of the tip in the diamond microdermabrasion system. [ 4 ]


Unlike the older crystal microdermabrasion system, the diamond microdermabrasion does not produce particles from crystals that may be inhaled into patients' nose or blown into the eyes. Hence, diamond microdermabrasion is regarded as having higher safety for use on areas around the eyes and lips. Generally, the slower the movement of the microdermabrasion handpiece against the skin and the greater the numbers of passes over the skin, the deeper the skin treatment. [ citation needed ]


One of the safest methods of microdermabrasion involves the use of corundum or aluminum oxide crystals suspended in an antioxidant cream.   This version of microdermabrasion is generally the most cost efficient as it involves the use of a small handheld skincare tool instead of expensive equipment used by a salon.  This method of microdermabrasion rose to popularity in the early 2000s and is widely available today.


Often called "microderm" for short, microdermabrasion is a procedure to help exfoliate or temporarily remove a few of the top layers of the skin called the stratum corneum. Much like brushing one's teeth, microdermabrasion helps to gently remove skin "plaque" and skin debris. [ citation needed ]  Since human skin typically regenerates at approximately 30-day intervals, skin improvement with microdermabrasion is temporary and needs to be repeated at average intervals of two - four weeks for continued improvement.  Multiple treatments in combination with sunscreen, sun avoidance and skin care creams yield best results.


Dermabrasion is generally used to refer to a true surgical procedure that aggressively abrades away the top to mid layers of the skin. The term microdermabrasion generally refers to a non-surgical procedure that abrades less deeply than dermabrasion. Although the mechanism of the two procedures is similar, the difference in the depth of the abrasion results in different recovery times. Dermabrasion recovery time may take as much as several weeks to several months whereas microdermabrasion recovery time may be as little as one to two days. [ 5 ]  After microdermabrasion, skin will be much more sensitive to sun exposure. It is best to keep out of the sun and wear sunscreen at all times after the procedure. [ citation needed ]


Microdermabrasion may be performed to help diminish the appearance of superficial  hyperpigmentation  or  photo-damage  (sunburn), as well as diminish fine lines, wrinkles, acne and shallow acne scars. A further benefit of microdermabrasion is enhanced skin penetration by skin creams and serums. Removing dead skin (stratum corneum of the epidermis) will aid in the penetration of skin care products and medications by up to 10-50%. The controlled skin exfoliation afforded by microdermabrasion will allow make-up and self-tanning products to go on much more smoothly. [ 6 ]


Microdermabrasion treatment carries minimal to very few possible side effects or complications. However, some patients may experience temporary mild dryness, sun sensitivity and rarely temporary bruising or scratches in the area of skin treated. [ citation needed ]


The first microdermabrasion unit was developed in  Italy  in 1985, using small inert  aluminium oxide  crystals to abrade the skin. In 1986, other European markets had introduced the technology which was immediately adopted by physicians for mechanical exfoliation. There were 10 microdermabrasion units on the market in Europe by the end of 1992. In 1996,  Mattioli Engineering  partnered with one of the Italian designed machines and started working towards meeting FDA requirements for the USA. By the end of 1996, the  Food and Drug Administration | (FDA) issued the first approval letter for microdermabrasion machines. In January 1997, the first microderm machine was being sold and marketed in the US. The diamond tip was introduced in 1999 and the bristle tip brush was introduced in 2005. [ 7 ]  The first standard vacuum based microdermabrasion system called Vacubrasion was introduced in 2012 in the US and world markets, and provides diamond tip exfoliation and suction. Vacubrasion's patented air regulator delivery system was designed and underwent extensive testing by US dermatologists and physicians. Its straightforward design revolutionized microdermabrasion to permit use of almost any type of suction source (primarily retail brand vacuums with a 1.25 in (31.8 mm) standard round hose such as Eureka, Stanley vacuums) with a non-disposable, attached electroplated fine diamond abrasive tip. While traditional, older crystal based microdermabrasion and home microdermabrasion systems are sometimes fraught with clogging issues and potential loss of suction, the crystal-free Vacubrasion systems utilize a universal, larger and more powerful suction source that avoids many of these issues. [ 8 ]


Microdermabrasion has evolved from  rocks , stones and  shells  to  crystals , particle-free diamond tips and particle-free bristle tips. Once the desired amount of exfoliation has been reached, some microdermabrasion units will then spray or infuse a skin enhancing solution into the skin. Since microderm essentially manually removes limited layers of the stratum corneum (dead layers of the outer layer of the skin), any serum or topical product applied in any fashion to the skin following microdermabrasion will potentially have a greater opportunity for penetration into the skin.


Microdermabrasion crystals are typically made of a very fine, abrasive material like  aluminum oxide . Other inert microderm crystals include magnesium oxide, sodium chloride, and sodium bicarbonate. All ultra-fine white crystals are disposable and should be discarded after each use. The microdermabrasion vacuum removes the crystals and exfoliated skin cells. Inhalation of crystals should be avoided and masks are sometimes worn by the operator doing the treatment. Ocular injury may occur if crystals are inadvertently sprayed in the eye or if crystals remain around the eye and cause a corneal abrasion. There are some possible concerns of inhalation exposure and basic safety precautions should be taken. Patient goggles or eye shields, as well as operator face masks are recommended when treating with crystal based systems. Alternatively, microderm crystals can be safely replaced by the roughened surface of a diamond tip microdermabrasion system. The newer diamond based systems like Vacubrasion utilize a fine  diamond dust  that is essentially electroplated onto a stainless steel round tip that comes in contact with the skin.


A  dermatome  is a  surgical instrument  for producing thin slices of  skin  from a donor area, for use in  skin grafts . One of its main applications is for reconstituting skin areas damaged by third degree  burns  or  trauma .


Dermatomes can be operated either manually or electrically. The first drum dermatomes, developed in the 1930s, were manually operated. Afterwards, dermatomes which were operated by air pressure, such as the Brown dermatome, achieved higher speed and precision. Electrical dermatomes are better for cutting out thinner and longer strips of skin with a more homogeneous thickness.


Those are manual dermatomes and the term  knife  or  scalpel  is used to describe them. Their disadvantages are harvesting of grafts with irregular edges and grafts of variable thickness. Their operator has to be experienced in their use for optimal results. [ 1 ]


There are several types of dermatomes, usually named after their inventor.


Duct tape occlusion therapy  (DTOT) is a method of treating  warts  by covering them with  duct tape  for prolonged periods.


The manner in which duct tape appears to work is unclear. [ 1 ]  The tape might create a  macerating  and  keratolytic  environment, stimulating an  immune response . [ 1 ]  The type of adhesive in the duct tape is likely to be important as leeching of the adhesive into the skin may be causing the immune system response. [ 2 ]   Side effects  can include skin irritation and peeling. [ 3 ]


There is mixed evidence that occlusive treatment with various types of duct tape is effective. [ 1 ]  Clinical trials in 2012 concluded that no  statistically significant  difference between clear duct tape and  placebo  could be determined within the sample. [ 1 ]  On health information websites, duct tape is referred to as a treatment with mixed evidence of efficacy, no good evidence or described as  alternative medicine . [ 3 ] [ 4 ] [ 5 ] [ 6 ] [ 7 ]


Despite the mixed evidence for efficacy, the simplicity of the method and its limited side-effects leads some researchers to be reluctant to dismiss it. [ 8 ]


In 1978, Jerome Z Litt was the first to suggest that adhesive tape could be used to treat warts on the fingers. He claimed: "My method is safe, easy, simple, painless, inexpensive, and highly effective. It leaves no scarring or deformed nails. The mystery remains: How and why does this method work? I cannot offer any reasonable or logical explanation. It cannot be all 'hypnotic' or 'suggestive.' Could it be that the airtight occlusion and a chemical reaction set up by the adhesive in the tape might combine to release a chemical or ' toxin ' causing the formation of  antibodies ? Whatever it may be, it works. I recommend that you try it." [ 9 ]


A 2002 study involved 51 individuals (aged 3–22) treated with either "standard duct tape" (not otherwise specified in the study) or cryotherapy. A piece of duct tape was cut as close to the size of the wart as possible, and applied to the area.  The tape was left on for 6 days and replaced with new duct tape if it fell off. After 6 days, the tape was removed, the area soaked in water, and the wart  debrided  with an  emery board  or  pumice stone . The tape was left off overnight and reapplied on the following morning. This process continued for up to 2 months or until the wart was resolved, whichever occurred first. Progress was monitored every 4 weeks. The researchers found the duct tape treatment significantly more effective than the cryotherapy (P=0.05) with 85% in the duct tape treatment group having a complete resolution of their wart, compared to 60% in the cryotherapy group. [ 10 ]  The study was criticized due to lack of a  placebo control group , [ 11 ]  and because a number of outcome assessments were done by phone. [ 12 ]  There was also no reported long term follow up to ensure no recurrence of the warts. [ 11 ] [ 10 ]


Two later studies failed to repeat the results of the 2002 study. [ 13 ] [ 14 ]  One compared duct tape with  moleskin , finding no statistically significant difference in results reported between the two groups. [ 14 ]  Both studies used 3M clear duct tape, again concluding no statistically significant effect on wart resolution. [ 13 ]  The  statistical power  of the latter trial has been questioned, [ 15 ]  and it has been suggested that duct tape occlusion therapy only works with rubber-based adhesives, whereas these studies utilized acrylic-based adhesive. [ 2 ]


Electrotrichogenesis  ( ETG ) involves the stimulation of  hair follicles  on the  scalp  with the  electric charge  of an  electrostatic field .


Three studies are listed in the  PubMed  database relating to the technique. [ 1 ] [ 2 ] [ 3 ]


Electrotrichogenesis was approved in Europe with the  CE mark , as a medical device.  It was also approved by Health Canada and the Australian health office. [ citation needed ]


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Facial rejuvenation  is a cosmetic treatment (or series of cosmetic treatments), which aims to restore a youthful appearance to the human  face . Facial rejuvenation can be achieved through either  surgical  and/or non-surgical options. Procedures can vary in  invasiveness  and depth of treatment. Surgical procedures can restore  facial symmetry  through targeted procedures and facial restructuring and skin alterations. Non-surgical procedures can target specific depths of facial structures and treat localized facial concerns such as  wrinkles , skin laxity,  hyperpigmentation  and  scars .


Surgical (invasive) facial rejuvenation procedures can include a  brow lift  (forehead lift), eye lift ( blepharoplasty ),  facelift  (rhytidectomy), chin lift and  neck lift . Non-surgical (non-invasive) facial rejuvenation treatments can include  chemical peels , neuromodulator (such as  botox ),  dermal fillers ,  laser resurfacing ,  photorejuvenation ,  radiofrequency  and  Ultrasound .


Human  visual perception  is notable for its sensitivity and accuracy in estimating our perceived age by instant  pattern recognition  of facial features. Often, human faces with no measurable difference in  facial geometry  and appearance are perceived as having different ages. This mechanism is not yet entirely understood, but there may be a relation to the subtle changes in facial bone structure related below. [ 1 ]


Facial symmetry  has a direct relationship to perceived beauty. A guiding approach to facial rejuvenation and balancing facial symmetry is through an application of the  golden ratio . [ 2 ]  Artists and architects have been using this ratio to create works that are pleasing to the eye for centuries. [ 3 ]   Aesthetic medicine  and facial rejuvenation techniques has adopted this mathematical approach to facial restoration and enhancement. [ 4 ]


More recent research has pointed out the influence of changes in the facial  skeleton  with age on the appearance of aging, especially in the mid-face area and the lower part of the  orbits  around the  nose . Quantitative study with  CAT scans  of the faces of men and women in several age brackets has revealed that there is an appreciable amount of   bone  tissue loss in these regions with age, leading to changes in angles, lengths and volumes, and also decreasing the distance between the  eyes . [ 4 ]  It has been hypothesized that skin sagging and wrinkles may occur not only because of loss of soft tissue and fat, but also because bone retraction creates an excess of skin which is no longer flexible. Many of the facial manifestations of aging reflect the combined effects of gravity, progressive  bone resorption , decreased tissue elasticity, and redistribution of subcutaneous fullness. [ 5 ]  Future facial rejuvenation techniques may take into account these findings and restore bone lost by aging processes. [ 6 ]


According to the  American Society of Plastic Surgeons , more than 133,000 facelifts and nearly 216,000 eyelid surgeries were performed in the US in 2013, a six per cent increase from 2012. Facial rejuvenation procedures experienced the most growth, as 2013 marked the highest number of botulinum toxin type A injections to date, with 6.3 million injections. [ 7 ]  A significant upward trend on the number of facial rejuvenation procedures is predicted, [ 5 ]  and could be due to the following factors:


However, while surgical procedures are still preferred to achieve a more dramatic improvement, the current trend is towards less invasive procedures, such as injectables (Botox, fillers) and laser skin treatments. While these treatments achieve temporary results, they tend to be preferred because of their reduced cost and less intensive recovery period. [ 6 ]


Facial rejuvenation procedures can include (but are not limited to):


Grenz rays  are part of the electromagnetic spectrum comprising low energy (ultrasoft)  X-rays . These were first investigated by  Gustav Bucky  in 1923 using a cathode vacuum tube with a lithium borate glass window, which he labeled Grenz rays as he believed that the biological effects resembled those of UV light and traditional X-rays and hence were on the border between the two ( Grenz  = border in German). These rays are also known as  Bucky rays . [ 1 ]


Grenz rays are produced by specially calibrated X-ray machines generally operating in the 10 to 30 kV range to produce X-rays with HVL less than 0.035 mm in aluminum. [ 2 ]  (HVL is  half-value layer , and refers to a thickness of a given material that will cut the X-ray flux by 50%). Grenz rays are absorbed by air and therefore treatments must be given at fixed distances for which the machine has been calibrated.  In human tissue Grenz rays have a half-value depth of 0.5 mm and are essentially absorbed within the first 2 mm of skin. [ 3 ]   The exact mechanism of action is unknown but it does have effects on the  Langerhans cells  in the epidermis. [ 4 ] [ 5 ]


Grenz rays are indicated for treatment of  eczema ,  psoriasis , palmoplantar pustulosis, neurodermatitis,  pruritus ani  and  pruritus vulvae . They have been reported to be helpful for lichen planus, Grover's disease, Darier's disease,  Hailey–Hailey disease [ 6 ]  and histiocytosis X. [ 2 ]  Grenz rays have also been used for treatment of  actinic keratosis  and  Bowen's disease . [ 1 ]


Hydradermabrasion  is a  dermatological  procedure which combines simultaneous dermal infusion of medicinal products and crystal-free  exfoliation . Hydradermabrasion's mechanism of actions includes: (a) mechanical stimulation activates the basal layer, and (b) thickening and smoothing the  epidermis .  Fibroblast  activity results in  extracellular matrix  deposition and dermal thickening.  Antioxidants  introduced through the procedure hydrate and decrease  inflammation  in the skin, reversing photo damage, while protecting lipid membranes, collagen fibers, and enzyme systems. [ 1 ]


It is considered to be a relatively new procedure which combines microdermabrasion with the pneumatic application of antioxidant-based serums. [ 2 ]  The addition of  polyphenolic  antioxidants through hydradermabrasion to a  phototherapy  regimen enhanced the clinical, biochemical, and histological changes seen following phototherapy alone. [ 3 ]


"Hydradermabrasion has the same indications for use as  microdermabrasion , making it an excellent choice for persons with darker skin tones, aging skin, sensitive skin areas, oily, and dry skin complexions". [ 4 ]  A study on the efficacy of hydradermabrasion for facial rejuvenation was conducted comparing volunteers who received hydradermabrasion facial treatments using an antioxidant serum or who just received the same antioxidant serum manually applied to the skin. [ 4 ]


Skin treated with Hydradermabrasion demonstrated "significantly increased epidermal and papillary dermal thickness, and increased fibroblast density (p<0.01)”. [ 5 ]  A study on the efficacy of hydradermabrasion for facial rejuvenation was conducted comparing volunteers who received hydradermabrasion facial treatments using an antioxidant serum or who just received the same antioxidant serum manually applied to the skin. Six treatments were conducted on a 7- to 10-day interval to determine whether antioxidant levels could be increased in the skin and skin quality improved with this technique. Results of this study demonstrated that hydradermabraded skin possessed increased epidermal and papillary dermal thickness as well as greater antioxidant levels. Further histological examination saw a replacement of elastic dermal tissue, collagen hyalinization, and fibroblast density correlating with a decrease in the appearance of fine lines, pore size, and hyperpigmentation in hydradermabrasion treated areas 6 weeks post-treatment with no patient complications. [ 4 ]


Instruments used specially in  dermatology  are as follows:


This article related to  medical equipment  is a  stub . You can help Wikipedia by  expanding it .


Lupus band test  is done upon  skin biopsy , with  direct immunofluorescence  staining, in which, if positive,  IgG  and  complement  depositions are found at the  dermoepidermal junction . [ 1 ] : 212    This test can be helpful in distinguishing  systemic lupus erythematosus  (SLE) from cutaneous lupus, because in SLE the lupus band test will be positive in both involved and uninvolved skin, whereas with cutaneous lupus only the involved skin will be positive. [ 1 ] : 212


The minimum criteria for positivity are: [ 2 ]


The presence of other immunoglobulins (especially  IgA ) and/or complement proteins (especially  C4 ) increases the  specificity  of a positive test. [ citation needed ]


The  management of hair loss , includes prevention and treatment of  alopecia ,  baldness , and  hair thinning , and regrowth of hair.


Scratching of itchy scalp may contribute to hair loss. [ 1 ]


Prevention of  obesity  helps. Obesity is linked to  hair thinning . [ 2 ]


Oils with fatty acids that has been studied to prevent dermatitis includes: [ 3 ] [ 4 ]


The scalp must be cleaned from  sebum , sweat, and dirt, prior to topical application, for agents to penetrate it.


A 2020  systemic review  on agents used to treat androgenic alopecia found that: [ 5 ]


A  humidifier  can be used to prevent low indoor humidity during  winter  (especially with indoor heating), and  dry season . [ 6 ]


Commonly, patients with  seborrhoeic dermatitis  experience mild redness, scaly skin lesions and in some cases  hair loss . [ 7 ]


Low humidity can cause adverse health effects and may cause  atopic dermatitis , [ 8 ]  and  seborrhoeic dermatitis . [ 9 ]


Combinations of finasteride, minoxidil and ketoconazole are more effective than individual use. [ 10 ]


Combination therapy of LLLT or microneedling with finasteride [ 11 ]  or minoxidil demonstrated substantive increases in hair count. [ 12 ]


The topical  bioavailability  of synthetic medicines such as  antiandrogens , as well as phytochemicals such as  quercetin , has been improved with incorporation of drugs in  nanoparticles , or  microneedling . [ 13 ]


Treatments for the various forms of hair loss have only moderate success. [ 14 ]  Three medications have evidence to support their use in male pattern hair loss:  finasteride ,  dutasteride  and  minoxidil . [ 15 ]  They typically work better to prevent further hair loss than to regrow lost hair. [ 15 ]


They may be used together when hair loss is progressive or further regrowth is desired after 12 months. [ 16 ]  Other medications include  ketoconazole , and in female androgenic alopecia  spironolactone  and  flutamide . [ 17 ]


In June 2022, the FDA authorized  baricitinib  for the treatment of severe alopecia areata. [ 18 ] [ 19 ]


Minoxidil , applied topically, is widely used for the treatment of hair loss. It may be effective in helping promote hair growth in both men and women with  androgenic alopecia . [ 20 ] [ 21 ]  About 40% of men experience hair regrowth after 3–6 months. [ 22 ]  It is the only topical product that is FDA approved in America for androgenic hair loss. [ 20 ]  However, increased hair loss has been reported. [ 23 ] [ 24 ]


Finasteride  is used to treat  male pattern hair loss . [ 25 ]  Treatment provides about 30% improvement in hair loss after six months of treatment, and effectiveness only persists as long as the drug is taken. [ 20 ]  There is no good evidence for its use in women. [ 14 ]  It may cause  gynecomastia ,  erectile dysfunction  and  depression . [ 26 ]


Dutasteride  is also used in the treatment of male pattern hair loss and appears to have better effectiveness than finasteride for the condition. [ 27 ] [ 28 ] [ 29 ]  While used off-label for male pattern hair loss in most of the world, dutasteride is specifically approved for this indication in  South Korea  and  Japan . [ 30 ] [ 31 ]


There is tentative support for  spironolactone  in women. [ 14 ]  Due to its feminising side effects and risk of infertility it is not often used by men. [ 32 ] [ 33 ]  It can also cause  low blood pressure ,  high blood potassium , and  abnormal heart rhythms . Also, women who are pregnant or trying to become pregnant generally cannot use the medication as it is a  teratogen , and can cause ambiguous genitalia in newborn children. [ 34 ]


There is tentative evidence for  flutamide  in women; however, it is associated with relatively high rates of liver problems and strong recommendations have been made against its use. [ 14 ] [ 35 ]  Like spironolactone, flutamide is typically only used by women. [ 36 ]   Bicalutamide  is another option for the treatment of female pattern hair loss. [ 37 ] [ 38 ] [ 39 ]  It has a far lower risk of liver toxicity than flutamide and is said to have an excellent safety profile. [ 38 ] [ 39 ] [ 40 ]  However, bicalutamide retains a small risk of liver toxicity and for this reason periodic liver monitoring is recommended during treatment. [ 38 ] [ 40 ]


Ketoconazole  may help in women. [ 41 ] [ 42 ]


Low-level laser therapy  or photobiomodulation is also referred to as red light therapy and cold laser therapy. It is a non-invasive treatment option.


LLLT is shown to increase hair density and growth in both genders. The types of devices (hat, comb, helmet) and duration did not alter the effectiveness, [ 43 ]  with more emphasis to be placed on lasers compared to LEDs. [ 44 ]  Ultraviolet and infrared light are more effective for alopecia areata, while red light and infrared light is more effective for androgenetic alopecia. [ 45 ]


Medical reviews suggest that LLLT is as effective or potentially more than other non invasive and traditional therapies like minoxidil and finasteride but further studies such as RCTs, long term follow up studies, and larger double blinded trials need to be conducted to confirm the initial findings. [ 46 ] [ 11 ] [ 47 ]


Using ones own cells and tissues and without harsh side effects, PRP is beneficial for alopecia areata [ 48 ]  and androgenetic alopecia and can be used as an alternative to minoxidil or finasteride. [ 49 ]  It has been documented to improve hair density and thickness in both genders. [ 50 ]  A minimum of 3 treatments, once a month for 3 months are recommended, and afterwards a 3-6 month period of continual appointments for maintenance. [ 51 ]  Factors that determine efficacy include amount of sessions, double versus single centrifugation, age and gender, and where the PRP is inserted. [ 52 ]


Future larger randomized controlled trials and other high quality studies are still recommended to be carried out and published for a stronger consensus. [ 46 ] [ 50 ] [ 53 ]  Further development of a standardized practice for procedure is also recommended. [ 48 ]


Hair transplantation is a  surgical  technique that moves individual  hair follicles  from a part of the body called the donor site to bald or balding part of the body known as the recipient site. It is primarily used to treat male pattern baldness. In this condition, grafts containing hair follicles that are genetically resistant to balding are transplanted to bald scalp. It is also used to restore  eyelashes ,  eyebrows , beard hair, chest hair, and pubic hair and to fill in scars caused by accidents or surgery such as face-lifts and previous hair transplants. Hair transplantation differs from  skin grafting  in that grafts contain almost all of the  epidermis  and  dermis  surrounding the hair follicle, and many tiny grafts are transplanted rather than a single strip of skin.


Since hair naturally grows in follicles in groups of 1 to 4 hairs,  transplantation  takes advantage of these naturally occurring follicular units. This achieves a more natural appearance by matching hair for hair through  Follicular unit transplantation  (FUT).


Donor hair can be harvested in two different ways. Small grafts of naturally-occurring units of one to four hairs, called  follicular units , can be moved to balding areas of the  hair restoration . These follicular units are surgically implanted in the scalp in very close proximity to one another and in large numbers. The grafts are obtained in one or both of the two primary methods of surgical extraction, follicular unit transplantation, colloquially referred to as "strip harvesting", or  Follicular Unit Extraction  (FUE), in which follicles are transplanted individually.


In FUT, a strip of skin containing many follicular units is extracted from the patient and dissected under a stereoscopic microscope. The site of the strip removal is stitched closed. Once divided into follicular unit grafts, each unit is individually inserted into small recipient sites made by an incision in the bald scalp. In the newer technique, roots are extracted from the donor area and divided into strips for transplantation. The strip, two to three millimeters thick, is isolated and transplanted to the bald scalp. [ 54 ]  After surgery, a bandage is worn for two days to protect the stitched strip during healing. A small strip scar remains after healing, which can be covered by scalp hair growing over the scar. [ 55 ]


Scalp reduction is a surgical procedure in which the hairless region of the scalp of a  bald man  is reduced. This procedure can reduce the area of the scalp without hair. [ 56 ] [ 57 ]


Bimatoprost  0.03% has been used to grow  eyebrows . [ 58 ]


The FP receptor agonist,  bimatoprost , in the form of an 0.03% ophthalmic solution termed  Latisse , is approved by the US  Food and Drug Administration  to treat  hypotrichosis  of the  eyelashes , in particular to darken and lengthen eyelashes for cosmetic purposes. [ 59 ]  Also, bimatoprost may be used to treat small or underdeveloped  eyelashes . [ 60 ] [ 61 ]


Some popular plant juices sold as hair serum may instead of growing human hair actually inhibit the growth, including  6-gingerol  found in  ginger . [ 62 ]


A small 2002 study demonstrated that treatment twice daily for six weeks with crude onion juice from Australian brown onion, re-growth hair on  alopecia areata  (spot baldness) in 86.9% of the 23 participants. [ 63 ]  Twice as many  flavonols  are found in  red onion  than in  yellow onion . [ 64 ]  Also, non-organic onions might contain pesticides on the peel and in the first scaly leaf. Compounds found in onion that stimulates hair growth:


Dietary supplements are not typically recommended. [ 70 ]  Many people use unproven treatments, [ 15 ]  but there is little evidence of the effectiveness of  vitamins , minerals, or other dietary supplements regrowing hair or retaining hair. [ 14 ]  There is no evidence for  biotin  (vitamin B7). [ 70 ]  While lacking both evidence and expert recommendation, there is a large market for hair growth supplements, especially for products that contain biotin.


However, one small trial of  saw palmetto  which shows tentative benefit in those with  mild to moderate androgenetic alopecia. [ 70 ]  There was no good evidence for  gingko ,  aloe vera ,  ginseng ,  bergamot , or  hibiscus  as of 2011. [ 71 ]


Radiation induces hair loss through damage to hair follicle stem cell progenitors and alteration of keratin expression. [ 72 ] [ 73 ]  Radiation therapy has been associated with increased  mucin  production in hair follicles. [ 74 ]


Studies have suggested electromagnetic radiation as a therapeutic growth stimulant in alopecia. [ 75 ]


Certain hair shampoos and ointments visually thicken existing hair, without affecting the growth cycle. [ 76 ]  There have also been developments in the fashion industry with  wig  design. The fashion accessory has also been shown to be a source of psychological support for women undergoing chemotherapy, with cancer survivors in one study describing their wig as a "constant companion". [ 77 ]  Other studies in women have demonstrated a more mixed psychosocial impact of hairpiece use. [ 78 ]


Specialized tattoos, commonly known as scalp micropigmentation, can mimic the appearance of a short buzzed haircut. [ 79 ]


Type 1 and 2 5α reductase enzymes  are present at  pilosebaceous units  in papillae of individual  hair follicles . They catalyse formation of the androgens testosterone and DHT, which in turn regulate hair growth. Androgens have different effects at different follicles: they stimulate  IGF-1  at facial hair, causing hair regrowth, but stimulate  TGF β1 ,  TGF β2 ,  dickkopf1  and  IL-6  at the scalp, causing hair follicle miniaturisation. [ 80 ]


Female androgenic alopecia is characterized by diffuse crown thinning without hairline recession, and like its male counterpart rarely leads to  total hair loss . [ 81 ]   Finasteride  and  minoxidil  are usually first line therapy for its treatment. Other options include topical or systemic  spironolactone  or  flutamide , although they have a high incidence of  feminising   side effects  and are better tolerated in female androgenic hair loss.


More advanced cases may be resistant or unresponsive to medical therapy, however, and require  hair transplantation . Naturally-occurring units of one to four hairs, called  follicular units , are excised and moved to areas of hair restoration. These follicular units are surgically implanted in the scalp in close proximity and in large numbers. The grafts are obtained from either  Follicular Unit Transplantation  (FUT) – colloquially referred to as "strip harvesting" – or  Follicular Unit Extraction  (FUE). In the former, a strip of skin with follicular units is extracted and dissected into individual follicular unit grafts. The surgeon then implants the grafts into small incisions, called recipient sites. [ 55 ] [ 82 ]  Specialized scalp tattoos can also mimic the appearance of a short buzzed haircut. [ 83 ]  Androgenic alopecia also occurs in women, and more often presents as diffuse thinning without hairline recession. Like its male counterpart, the condition rarely leads to  total hair loss . Treatment options are similar to those for men, although topical or systemic estrogen is used more often. [ 81 ] [ 84 ]


Latanoprost  and  bimatoprost  are specific PGF2a analogues applied topically, and have been found to lengthen eyelashes, [ 85 ] [ 86 ]  darken hair pigmentation [ 87 ]  and elongate hair. [ 17 ]  Bimatoprost is available as treatment for eyelash growth. [ 88 ]  Latanoprost has shown ability to promote scalp hair density and pigmentation, [ 89 ]  and is theorized to function at the  dermal papilla . [ 90 ]  A study found latanoprost ineffective on eyelashes in a patient with  alopecia areata . [ 91 ]  It has also been found ineffective in treatment of eyebrow hair loss. [ 92 ]


Estrogens are indirect anti-androgens and can be used to treat androgenetic hair loss in women with  oral contraceptives . Systemic estrogen increases SHBG, which binds androgens, including testosterone and DHT, in turn reducing their bioavailability. Topical formulations are available in  Europe . [ 71 ]  Hair follicles have estrogen receptors and it is theorized that topical compounds act on them directly to promote hair growth and antagonize androgen action. Large clinical studies showing effectiveness are absent. Topical treatment is also usually unavailable in  North America . [ 17 ]


There is tentative evidence for  cyproterone acetate  in women. [ 14 ]


In December 2012, topical application of  IGF-1  in a liposomal vehicle led to thicker and more rapid hair growth in transgenic mice with androgenic alopecia. The study did not show measurable systemic levels or hematopoietic side effects, suggesting potential for use in humans. [ 93 ]  Low energy radiofrequency irradiation induces IGF-1 in cultured human dermal papilla cells. [ 94 ]  Adenosine stimulates dermal papillae in vitro to induce IGF-1, along with fibroblast growth factors  FGF7 ,  FGF-2  and  VEGF .  β-catenin  transcription increased, which promotes dermal papillae as well. [ 94 ]  Dietary  isoflavones  increase IGF production in scalp  dermal papillae  in transgenic mice. [ 95 ]  Topical capsaicin also stimulates IGF at hair follicles via release of vanilloid receptor-1, which in turn leads to more CGRP. [ 96 ]  Ascorbic acid has led to increased IGF expression  in vitro . [ 97 ]


Although follicles were previously thought gone in areas of complete baldness, they are more likely dormant, as recent studies have shown the scalp contains the  stem cells  from which the follicles arose. [ 98 ]  Research on these follicular stem cells may lead to successes in treating baldness through  hair multiplication  (HM), also known as  hair cloning .


Per a May 2015 review, no successful strategy to generate human hair follicles, for hair regrowth,  from adult stem cells has yet been reported. [ 99 ]   However, in April 2016, scientists from Japan published results of their work in which they created human skin from  induced pluripotent stem cells ; implanted into laboratory mice, the cells generated skin with hair and glands. [ 100 ]


From 2005 to 2007, Curis and  Procter & Gamble  collaborated on developing a topical  hedgehog   agonist  for hair loss; the agent did not meet safety standards, and the program was terminated. [ 101 ] [ 102 ]  In 2008, researchers at the  University of Bonn  announced they have found the genetic basis of two distinct forms of inherited hair loss. They found the gene  P2RY5  causes a rare, inherited form of hair loss called hypotrichosis simplex. It is the first  receptor  in humans known to play a role in hair growth. [ 103 ] [ 104 ] [ 105 ]  Researchers found that disruption of the  gene   SOX21  in mice caused cyclical hair loss.  Research has suggested SOX21 as a master regulator of hair shaft cuticle differentiation, with its disruption causing cyclical alopecia in mice models. [ 106 ]  Deletion of SOX21 dramatically affects hair lipids. [ 107 ]


The  Mantoux test  or  Mendel–Mantoux test  (also known as the  Mantoux screening test ,  tuberculin sensitivity test ,  Pirquet test , or  PPD test  for purified protein derivative) is a tool for  screening  for  tuberculosis (TB)  and for  tuberculosis diagnosis . It is one of the major  tuberculin  skin tests used around the world, largely replacing multiple-puncture tests such as the  tine test . The  Heaf test , a form of tine test, was used until 2005 in the UK, when it was replaced by the Mantoux test. The Mantoux test is endorsed by the  American Thoracic Society  and  Centers for Disease Control and Prevention . It was also used in the  USSR  and is now prevalent in most of the  post-Soviet states , although Soviet mantoux produced many false positives due to children's allergic reaction. [ 1 ]


Tuberculin  is a  glycerol  extract of the tubercle  bacillus .  Purified protein derivative (PPD) tuberculin is a precipitate of species-nonspecific molecules obtained from filtrates of sterilized, concentrated cultures. The tuberculin reaction was first described by  Robert Koch  in 1890. The test was first developed and described by the German physician Felix Mendel in 1908. [ 2 ]  It is named after  Charles Mantoux , a French physician who built on the work of Koch and  Clemens von Pirquet  to create his test in 1907. However, the test was unreliable due to impurities in tuberculin which tended to cause false results. [ 3 ]


Esmond R. Long  and  Florence B. Seibert  identified the active agent in tuberculin as a protein.  Seibert then spent a number of years developing methods for separating and purifying the protein from  Mycobacterium tuberculosis , obtaining purified protein derivative (PPD) and enabling the creation of a reliable test for tuberculosis. [ 3 ]   Her first publication on the purification of tuberculin appeared in 1934. [ 4 ]  By the 1940s, Seibert's PPD was the international standard for tuberculin tests. [ 5 ]  In 1939,  Russian  M.A. Linnikova created a modified version of PPD. In 1954, the Soviet Union started mass production of PPD-L, named after Linnikova. [ 6 ] [ 7 ]


In the Mantoux test, a standard dose of 5 tuberculin units (TU - 0.1 ml), according to the  CDC , [ 8 ]  or 2 TU of Statens Serum Institute (SSI) tuberculin RT23 in 0.1 ml solution, according to the  National Health Service , [ 9 ]  is injected intradermally (between the layers of dermis) on the flexor surface of the left forearm, mid-way between elbow and wrist. The injection should be made with a tuberculin syringe, with the needle bevel facing upward. When placed correctly, injection should produce a pale wheal of the skin, 6 to 10 mm in diameter. The result of the test is read after 48–96 hours, ideally after 72 hours/3rd day. This procedure is termed the 'Mantoux technique'. A person who has been exposed to the bacteria would be expected to mount an immune response in the area of skin containing the bacterial proteins. This response is a classic example of 'delayed-type hypersensitivity reaction' ( DTH ), a  type IV  of  hypersensitivities .  T cells  and myeloid cells are attracted to the site of reaction in 1–3 days and generate local  inflammation . The reaction is read by measuring the diameter of  induration  (palpable raised, hardened area) across the forearm (perpendicular to the long axis) in millimeters. If there is no induration, the result should be recorded as "0 mm".   Erythema  (redness) should not be measured. [ 10 ]  In the Pirquet version of the test  tuberculin is applied to the skin via  scarification . [ 11 ]


The results of this test must be interpreted carefully.  The person's medical risk factors determine at which increment (5 mm, 10 mm, or 15 mm) of induration the result is considered positive. [ 12 ]  A positive result indicates TB exposure.


A tuberculin test conversion is defined as an increase of 10 mm or more within a two-year period, regardless of age. Alternative criteria include increases of 6, 12, 15 or 18 mm. [ 14 ]


TST (tuberculin skin test) positive is measured by size of induration. The size of the induration considered to be a positive result depends on risk factors. For example, a low-risk patient must have a larger induration for a positive result than a high-risk patient. High-risk groups include recent contacts, those with HIV, those with chest  radiograph  with fibrotic changes, organ transplant recipients, and those with immunosuppression. [ citation needed ]


A meta-analysis in 2014 found that the  Bacillus Calmette–Guérin (BCG) vaccine  reduced infections by 19–27% and reduced progression to active tuberculosis by 71%. [ 15 ]  The Ohio Department of Health states that it give 80% of children protection against  tuberculous meningitis  and  miliary tuberculosis . Therefore, a positive TST/PPD in a person who has received BCG vaccine is interpreted as latent TB infection (LTBI). [ 16 ]
Due to the test's low specificity, most positive reactions in low-risk individuals are false positives. [ 17 ]  A false positive result may be caused by  nontuberculous mycobacteria  or previous administration of BCG vaccine.  Vaccination with BCG may result in a false-positive result for many years after vaccination. [ 18 ]


False positives can also occur when the injected area is touched, causing swelling and itching. If the swelling is less than 5 mm, it is possibly due to error by the healthcare personnel causing inflammation to the area. [ citation needed ]


Another source of false positive results can be allergic reaction or  hypersensitivity . Although rare (about 0.08 reported reactions per million doses of tuberculin), these reactions can be dangerous and precautions should be taken by having  epinephrin  available. [ 19 ]


Reaction to the PPD or tuberculin test is suppressed by the following conditions:


This is because the immune system needs to be functional to mount a response to the protein derivative injected under the skin. A false negative result may occur in a person who has been recently infected with TB, but whose immune system hasn't yet reacted to the bacteria.


In case a second tuberculin test is necessary it should be carried out in the other arm to avoid hypersensitising the skin.


The role of Mantoux testing in people who have been vaccinated is disputed.  The US recommends that tuberculin skin testing is not contraindicated for BCG-vaccinated persons, and prior BCG vaccination should not influence the interpretation of the test.  The UK recommends that  interferon-γ  testing should be used to help interpret positive Mantoux tests of over 5 mm, [ 20 ]  and repeated tuberculin skin testing must not be done in people who have had BCG vaccinations. In general, the US recommendation may result in a larger number of people being falsely diagnosed with latent tuberculosis, while the UK approach has an increased chance of missing patients with latent tuberculosis who should be treated. [ citation needed ]


According to the US guidelines,  latent tuberculosis  infection diagnosis and treatment is considered for any BCG-vaccinated person whose skin test is 10 mm or greater, if any of these circumstances are present: [ citation needed ]


In cases of  anergy , a lack of reaction by the body's defence mechanisms when it comes into contact with foreign substances, the tuberculin reaction will occur weakly, thus compromising the value of Mantoux testing. For example, anergy is present in  AIDS , a disease which strongly depresses the immune system. Therefore, anergy testing is advised in cases where there is suspicion that anergy is present. However, routine anergy skin testing is not recommended. [ 21 ]


Some people who have been infected with TB may have a negative reaction when tested years after infection, as the immune system response may gradually wane. This initial skin test, though negative, may stimulate (boost) the body's ability to react to tuberculin in future tests. Thus, a positive reaction to a subsequent test may be misinterpreted as a new infection, when in fact it is the result of the boosted reaction to an old infection. [ 22 ]


Use of two-step testing is recommended for initial skin testing of adults who will be retested periodically (e.g., health care workers). This ensures any future positive tests can be interpreted as being caused by a new infection, rather than simply a reaction to an old infection. [ citation needed ]


A person who is diagnosed as "infected in the distant past" on two-step testing is called a "tuberculin reactor". [ citation needed ]


The US recommendation that prior BCG vaccination be ignored results in almost universal false diagnosis of tuberculosis infection in people who have had BCG (mostly foreign nationals). [ citation needed ]


According to the guidelines published by Centers for Disease Control and Prevention in 2005, the results are re-categorized into 3 parts based on their previous or baseline outcomes: [ citation needed ]


In addition to tuberculin skin tests such as (principally) the Mantoux test,  interferon gamma release assays  (IGRAs) have become common in clinical use in the 2010s. In some contexts they are used instead of TSTs, whereas in other contexts TSTs and IGRAs both continue to be useful. [ 25 ]


The  QuantiFERON-TB Gold  blood test measures the patient's immune reactivity to the TB bacterium, and is useful for initial and serial testing of persons with an increased risk of latent or active tuberculosis infection. Guidelines for its use were released by the CDC in December 2005. [ 26 ]  QuantiFERON-TB Gold is  FDA -approved in the  United States , has  CE Mark  approval in  Europe  and has been approved by the  MHLW  in  Japan . The interferon gamma release assay is the preferred method for patients who have had immunosuppression and are about to start biological therapies. [ 27 ]


T-SPOT.TB  is another IGRA; it uses the  ELISPOT  method. [ citation needed ]


The Heaf tuberculin skin test was used in the United Kingdom, but discontinued in 2005. The equivalent Mantoux test positive levels done with 10 TU (0.1 ml at 100 TU/ml, 1:1000) are [ citation needed ]


The  Prausnitz–Küstner test  (PK test, Prausnitz-Küstner reaction) is an  immunologic  test formerly used by physicians to determine if a patient has an allergic reaction to a specific  antigen . [ 1 ]   The test has been replaced by the safer  skin prick test .  The PK test involves transferring  serum  from the test subject to another healthy person, essentially using the second person as a mixing vessel for antibodies and antigen.  This is a pathway for transmission of blood-borne ailments like  variant Creutzfeldt–Jakob disease ,  AIDS , and others, which is why the test is no longer recommended.
Or in simple words, a test for the presence of immediate hypersensitivity in humans; test serum from an  atopic  individual is injected intradermally into a normal subject; the normal subject is challenged 24–48 hours later with the antigen suspected of causing the immediate hypersensitivity reaction in the atopic individual.


Serum, suspected to contain  IgE   antibodies , is drawn from the allergic (atopic) patient. [ 1 ]   This serum is injected  intradermally  into a non-allergic person.  The suspected antigens are then intradermally injected into the non-allergic person 24–48 hours later. [ 1 ]   If the person being tested for an allergy has made antibodies for the antigen, this will cause a local reaction in the non-allergic person when the antibodies mix with the antigen.  This demonstrates a  type I hypersensitivity  reaction, and the allergic reaction to the injected antigen is confirmed for the patient being tested.  A positive PK test usually appears as a  wheal and flare .


The test was developed by  Otto Prausnitz  and  Heinz Küstner . [ 1 ]   The first PK test occurred in 1921 when Prausnitz injected Küstner's serum into his abdominal skin. [ 2 ] [ 3 ]  Küstner had previously noted that he developed allergic symptoms after eating fish.  After eating some fish, Prausnitz's skin became hot, red, and swollen at the site of the serum injection, confirming their hypothesis that Küstner was allergic to fish. [ citation needed ]


A  reversed Prausnitz–Küstner test  involves injecting antibodies into the skin of a person who already has the antigen. [ 1 ]   A wheal and flare in the skin also demonstrates a positive reverse PK test.


Skin allergy testing  comprises a range of methods for medical diagnosis of  allergies  that attempts to  provoke  a small, controlled, allergic response.


A microscopic amount of an  allergen  is introduced to a patient's skin by various means: [ 1 ]


If an immuno-response is seen in the form of a  rash ,  urticaria  ( hives ), or  anaphylaxis  it can be concluded that the patient has a  hypersensitivity  (or  allergy ) to that  allergen . Further testing can be done to identify the particular allergen. [ citation needed ]


The "skin scratch test" as it is called, is not very commonly used due to the increased likelihood of infection. On the other hand, the "skin scrape test" is painless, does not leave residual pigmentation, and does not have a risk of infection, since it is limited to the superficial layer of the skin. [ citation needed ]


Some allergies are identified in a few minutes but others may take several days. In all cases where the test is positive, the skin will become raised, red, and appear itchy. The results are recorded - larger wheals indicating that the subject is more sensitive to that particular allergen. A negative test does not conclusively rule out an allergy; occasionally, the concentration needs to be adjusted, or the body fails to elicit a response. [ citation needed ]


In the prick, scratch and scrape tests, a few drops of the purified allergen are gently pricked on to the skin surface, usually the forearm. This test is usually done in order to identify allergies to  pet dander , dust,  pollen , foods or  dust mites . Intradermal injections are done by injecting a small amount of allergen just beneath the skin surface. The test is done to assess allergies to drugs like  penicillin [ 5 ]  or bee venom.


To ensure that the skin is reacting in the way it is supposed to, all skin allergy tests are also performed with proven allergens like  histamine , and non-allergens like  glycerin . The majority of people do react to histamine and do not react to glycerin. If the skin does not react appropriately to these allergens then it most likely will not react to the other allergens. These results are interpreted as falsely negative. [ 6 ]


The patch test uses rectangles of special hypoallergenic adhesive tape with different allergens on them. The patch is applied to the skin, usually on the back. The allergens on the patch include latex, medications, preservatives, hair dyes, fragrances, resins, and various metals. [ 7 ]  Patch testing is used to detect allergic  contact dermatitis  but does not test for  hives  or food allergy. [ 8 ]


Also called an  intradermal test , this skin end point titration (SET) uses an intradermal injection of allergens at increasing concentrations to measure allergic response. [ 9 ]  To prevent a severe allergic reaction, the test is started with a very dilute solution. After 10 minutes, the injection site is measured to look for growth of wheal, a small swelling of the skin. Two millimeters of growth in 10 minutes is considered positive. If 2 mm of growth is noted, then a second injection at a higher concentration is given to confirm the response. The end point is the concentration of antigen that causes an increase in the size of the wheal followed by confirmatory whealing. If the wheal grows larger than 13 mm, then no further injections are given since this is considered a major reaction. [ citation needed ]


There are no major preparations required for  skin testing . At the first consult, the subject's medical history is obtained and physical examination is performed. All patients should bring a list of their medications because some may interfere with the testing. Other medications may increase the chance of a severe allergic reaction. Medications that commonly interfere with skin testing include the following:


Patients who undergo skin testing should know that  anaphylaxis  can occur anytime. So if any of the following symptoms are experienced, a physician consultation is recommended immediately:


Even though skin testing may seem to be a benign procedure, it does have some risks, including swollen red bumps (hives) which may occur after the test. The  hives  usually disappear in a few hours after the test. In rare cases they can persist for a day or two. These hives may be itchy and are best treated by applying an over the counter  hydrocortisone  cream. [ 11 ]
In very rare cases one may develop a full blown allergic reaction. Physicians who perform skin test always have equipment and medications available in case an anaphylaxis reaction occurs. This is the main reason why people should not get skin testing performed at corner stores or by people who have no medical training. [ citation needed ]


Antihistamines , which are commonly used to treat allergy symptoms, interfere with skin tests, as they can prevent the skin from reacting to the allergens being tested. People who take an antihistamine need either to choose a different form of allergy test or to stop taking the antihistamine temporarily before the test. The period of time needed can range from a day or two to 10 days or longer, depending on the specific medication. Some medications not primarily used as antihistamines, including  tricyclic antidepressants ,
 phenothiazine -based antipsychotics, and several kinds of medications used for gastrointestinal disorders, can similarly interfere with skin tests. [ 12 ]


People who have severe, generalized  skin disease  or an acute skin infection should not undergo skin testing, as one needs uninvolved skin for testing. Also, skin testing should be avoided for people at a heightened risk of anaphylactic shock, including people who are known to be highly sensitive to even the smallest amount of allergen. [ 13 ]


Besides skin tests, there are blood tests which measure a specific  antibody  in the blood. The  IgE  antibody plays a vital role in allergies but its levels in blood do not always correlate with the allergic reaction. [ 14 ]


There are many alternative health care practitioners who perform a variety of provocation neutralization tests, but the vast majority of these tests have no validity and have never been proven to work scientifically.


Skin window technique  is used in  immunology  where the top layer of skin is scraped off making it possible to identify the immune response that would occur with a diminished physical barrier in the  host , and observe mobilization of  leukocytes . [ 1 ]


It was developed by  John Rebuck  in 1955. [ 2 ] [ 3 ]


This  immunology  article is a  stub . You can help Wikipedia by  expanding it .


Suction blistering  is a technique used in  dermatology  to treat chronic wounds, such as non-healing leg  ulcers . When a wound is not healing properly, an autologous  skin graft  is the best option, to prevent rejection of the tissue. Since autologous transplantation cannot always be performed, a substitute has to be used, such as cultured skin. However, this technique is costly and time-consuming. Other uses of suction blisters are to provide transplantation donor tissue for vitiligo research. Suction blisters are often used in tissue serum research in the pharmaceutical and cosmetic research fields. Many research citations are published worldwide that support these uses.


During suction blistering, the  lamina lucida  of the skin is cleaved from the underlying layers. This separates the  epidermis  from the  dermis . With the use of small vacuum pumps, little fluid-filled blisters are created, typically on the  abdomen . Blisters are usually formed within 2 to 3 hours. A well-recognized instrument, the Negative Pressure Instrument, from Electronic Diversities, Finksburg MD, US, is used with heated chambers to produce various-sized suction blisters with less time and improved success. [ citation needed ]


[ 1 ]  The blisters are then cut, emptied and the loose skin is transferred side by side to the non-healing wound. [ citation needed ]


Subsequently, the donor-site is treated with antiseptic drugs and covered with bandages. The acceptor-site is treated with non-adherent bandages, to prevent the skin graft from sticking to the bandages.


Tattoo removal  is the process of removing an unwanted  tattoo . The  process of tattooing  generally creates permanent markings in the skin, but people have attempted many methods to try to hide or destroy tattoos.


The standard modern method is the non-invasive removal of tattoo pigment using  Q-switched lasers . [ 1 ]  Different types of Q-switched lasers are used to target different colors of  tattoo ink ; depending on the specific light absorption spectra of the tattoo pigments. Typically, black and other darker-colored inks can be removed completely using Q-switched lasers, while lighter colors, such as yellows and greens, are very difficult to remove. Success depends on a wide variety of factors including skin color, ink color, and the depth at which the ink was applied. [ 2 ] [ 1 ]


Recent research has investigated the potential of multi-pass treatments and the use of  picosecond  laser technology. [ 3 ] [ 4 ] [ 5 ]


Before tattoo removal with Q-switched lasers began in the early 1990s,  continuous-wave lasers  were the standard method for tattoo removal. Continuous-wave lasers used a high energy beam that ablated the target area and destroyed surrounding tissue structures as well as tattoo ink. Treatment tended to be painful and cause significant scarring. [ 2 ] [ 1 ]


Prior to the development of  laser  tattoo removal methods, common techniques included  dermabrasion , TCA ( Trichloroacetic acid , an  acid  that removes the top layers of  skin , reaching as deep as the layer in which the tattoo ink resides), Sal abrasion (scrubbing the skin with  salt ),  cryosurgery , and  excision , which is sometimes still used along with skin grafts for larger tattoos. [ 6 ] [ 1 ] [ 7 ]  Many other methods for removing tattoos have been suggested historically, including the injection or application of  tannic acid ,  lemon juice ,  garlic , and  pigeon  dung. [ 8 ] [ 9 ]


Saline  is used to lighten  tattoos  (including  microblading  tattoos) through the process of  osmosis . [ 10 ] [ 11 ] [ 12 ] [ 13 ]


A poll conducted in January 2012 by  Harris Interactive  reported that 1 in 7 (14%) of the 21% of American adults who have a tattoo  regret  getting one. The poll did not report the reasons for these regrets, but a poll that was conducted four years prior reported that the most common reasons were "too young when I got the tattoo" (20%), "it's permanent," "I'm marked for life" (19%), and "I just don't like it" (18%). An earlier poll showed that 19% of Britons with tattoos experienced regret, as did 11% of Italians with tattoos. [ 14 ]


Surveys of tattoo removal patients conducted in 1996 and 2006 provided more insight. Of those polled, the patients who regretted their tattoos typically obtained their tattoos in their late teens or early twenties and were evenly distributed by gender. Among those seeking removals, more than half reported that they "suffered embarrassment." [ 15 ]  A new job, problems with clothes, and a significant life event were also commonly cited as motivations. [ 15 ]  Tattoos that were once a symbol of inclusion in a group, such as a gang, can make it difficult to gain employment. [ 2 ]  Tattoos that indicate a significant relationship, such as a spouse, girlfriend, or boyfriend, can become problematic if the relationship ends. [ 16 ]  Celebrities that have had these kinds of tattoos removed include  Angelina Jolie ,  Eva Longoria ,  Marc Anthony , and  Denise Richards . [ 17 ]


Some people decide to cover an unwanted tattoo with a new tattoo. A skillful cover-up may completely hide the old tattoo, or it may partially hide the old tattoo, depending on the size, style, colors and techniques used on the old tattoo and the skill of the tattoo artist. [ 18 ]  Covering up a previous tattoo requires darker tones in the new tattoo to effectively hide the unwanted piece. [ 19 ]  For tattoos that are especially difficult to cover up, a person may choose to get laser tattoo removal to lighten the ink to make the area easier to cover with a new tattoo. [ 20 ]


Tattoo removal is most commonly performed using lasers that break down the ink particles in the tattoo into smaller particles. Dermal  macrophages  are part of the immune system, tasked with collecting and digesting cellular debris. In the case of tattoo pigments, macrophages collect ink pigments, but have difficulty breaking them down. Instead, they store the ink pigments. If a macrophage is damaged, it releases its captive ink, which is taken up by other macrophages. This can make it particularly difficult to remove tattoos. When treatments break down ink particles into smaller pieces, macrophages can more easily remove them. [ 21 ]


Tattoo pigments have specific light absorption spectra. A tattoo laser must be capable of emitting adequate  energy  within the given  absorption spectrum  of the  pigment  to provide an effective treatment. Certain tattoo pigments, such as yellows and fluorescent inks are more challenging to treat than darker blacks and blues, because they have absorption spectra that fall outside or on the edge of the emission spectra of the tattoo removal laser. [ 6 ]  Recent pastel-cultured inks contain high concentrations of  titanium dioxide , which is highly reflective. Such inks are difficult to remove because they reflect a significant amount of the incident light energy out of the skin. [ 22 ] [ 6 ]