Hair loss patterns , known as male-pattern hair loss (MPHL ) when affecting men and female hair loss patterns b> ( FPHL ) when affecting women, is hair loss that mainly affects the top and front of the scalp. In men hair loss often appears as a receding hairline while in women it usually appears as hair thinning.
Male hair loss patterns are believed to be due to a combination of male genetics and dihydrotestosterone hormones. The cause of female hair loss patterns remains unclear.
Management may include accepting only those conditions. Otherwise, treatment may include minoxidil surgery, finasteride, or hair transplant. The evidence for finasteride in women, however, is poor and can result in birth defects if taken during pregnancy.
The pattern of hair loss at age 50 affects about half of men and a quarter of women. This is the most common cause of hair loss.
Video Pattern hair loss
Signs and symptoms
The loss of male hair-the classic pattern begins above the temple and vertex (calvaria) of the scalp. As time passes, the rim of hair on the side and back of the head remains. It has been referred to as 'Hippocratic wreath', and rarely develops to complement baldness. The Hamilton-Norwood scale has been developed to assess androgenic alopecia in males.
Female pattern hair loss more often causes thinning to spread without hair recession; similar to the male partner, female androgenic alopecia rarely causes total hair loss. Ludwig scale severity of female pattern hair loss.
Maps Pattern hair loss
Cause
Hormones
Research shows that early programming of pilosebaceous hair follicle units begins in utero . Physiology is mainly androgenic, with dihydrotestosterone (DHT) being a major contributor to dermal papillae. Men with premature androgenic alopecia tend to have lower than normal globulin sex hormone binding hormone (SHBG), follicle stimulating hormone (FSH), testosterone, and epitestosterone when compared with men without hair loss patterns. Although hair follicles were previously thought to be permanently lost in areas of complete hair loss, they are more likely to be inactive, because recent research shows the scalp contains the stem cell progenitor cells from which the follicles appear.
Transgenic studies have shown that growth and dormancy of hair follicles are associated with growth factor activity such as insulin (IGF) in dermal papillae, which is affected by DHT. Androgens are important in male sexual development around birth and at puberty. They regulate sebaceous glands, apocrine hair growth, and libido. With age, androgens stimulate hair growth on the face, but can suppress it in the temples and scalp vertex, a condition that has been termed the 'androgen paradox'.
Men with androgenic alopecia usually have a higher 5-alpha-reductase, lower total testosterone, higher free/free testosterone, and higher free androgens, including DHT. 5-alpha-reductase converts free testosterone to DHT, and is highest in the scalp and prostate gland. DHT most often formed at the network level by 5? -testosterone reduction. A genetic conclusion encoding this enzyme has been found. Prolactin has also been suggested to have different effects on hair follicles throughout the sexes.
Also, crosstalk occurs between androgens and the Wnt-beta-catenin signaling pathway which causes hair loss. At the level of somatic stem cells, androgens increase papillae differentiation of facial skin, but inhibit it in the scalp. Other studies have demonstrated the enzyme prostaglandin D2 synthase and D2 prostaglandin products (PGD2) in the hair follicles as their contribution.
These observations have led to studies at the level of mesenchymal dermal papillae. Type 1 and 2 5? the enzyme reductase is present in the pilosebaceous unit in the papillae of each hair follicle. They catalyze the formation of testosterone androgens and DHT, which in turn regulates hair growth. Androgens have different effects on different follicles: they stimulate IGF-1 in facial hair, which leads to growth, but also can stimulate TGF? 1, TGF? 2, dickkopf1, and IL-6 on the scalp, leading to the miniaturization of the catagenic. Hair follicles in anaphase express four different caspases.
The fact that hair loss is cumulative with age while decreased androgen levels as well as the fact that finasteride does not reverse the advanced stages of androgenetic alopecia remains a mystery but some explanations may have been posed: 1. Testosterone conversion to a higher DHT locally with higher age of 5-alpha reductase is recorded in bald scalp, and 2. Higher rates of DNA damage in Dermal Papilla as well as aging of Dermal Papilla due to activation of Androgen Receptors and environmental stress. The mechanism by which androgen receptors trigger permanent aging of Dermal Papilla is unknown but may involve IL6, TGFB-1 and oxidative stress. Aging papilla dermis is measured by a lack of mobility, different size and shape, lower replication and different molecular output changes and expression markers. The Dermal Papilla is the prime location of androgen action and migration toward the hair bulge and further signaling and increasing the size necessary to maintain the hair follicle so that aging through the androgen receptor explains a lot of physiology.
Diagnosis
The diagnosis of androgenic alopecia can usually be determined by clinical presentation in men. In women, diagnosis usually requires a more complex diagnostic evaluation. Further evaluation of the differential requires the exclusion of other causes of hair loss, and assesses the progressive hair loss pattern typical of androgenic alopecia. Trichoscopy can be used for further evaluation. Biopsy may be needed to rule out other causes of hair loss, and histology will show peripheracular fibrosis.
Treatment
Medication
Hair loss can be slowed or restored at an early stage with medication. Drugs approved by the US Food and Drug Administration (FDA) to treat hair loss in men include minoxidil and finasteride. The ketoconazole shampoo also exhibits consistent efficacy in enhancing both androgenetic alopecia by either antiandrogenic effects or by increasing seborrhoeic dermatitis which exacerbates androgenetic hair loss.
Androgen-dependent
Finasteride is a drug of the 5th grade? -reductase inhibitors (5-ARIS). By inhibiting type II-5 ARI, finasteride prevents the conversion of testosterone into dihydrotestosterone in various tissues including the scalp. Increased hair on the scalp can be seen within three months since starting treatment of finasteride and long-term studies have shown scalp hair increase at 24 and 48 months with continued use. Treatment with finasteride is more effective at treating male pattern hair loss in the vertex than in male-pattern hair loss patterns on the front of the head and temples.
Dutasteride is a drug in the same class as finasteride but it inhibits both type I and type II 5-alpha reductase. Dutasteride is approved for male pattern hair loss treatments in Korea and Japan, but not in the United States. However, it is usually used off-label to treat hair loss in men. Androgen-independent
Minoxidil dilates small blood vessels; it is not clear how this causes hair to grow. Other treatments include tretinoin combined with minoxidil, ketoconazole shampoo, spironolactone, alfatradiol, and topilutamide (fluridil).
Procedures
More sophisticated cases may be resistant or unresponsive to medical therapy and require a hair transplant. The natural unit of one to four hairs, called the follicular unit, is cut and moved into the hair restoration area. This follicular unit is grown on the scalp at close range and in large quantities. The graft is obtained from a transplanted follicle unit (FUT) or follicle extraction unit (FUE). In the first, the skin strips with the follicular units are extracted and dissected into graft of individual follicular units. The surgeon then instills a slice into a small incision, called the receiving site. Cosmetic scalp tattoos can also mimic the appearance of short and buzzing haircuts.
Alternative therapy
Many people use unproven care. There is no evidence for vitamins, minerals, or other dietary supplements. In 2008, there was little evidence supporting the use of lasers to treat hair loss in men. The same goes for special lights. Food supplements are usually not recommended. The 2015 review found more papers where plant extracts were studied but only one randomized, controlled clinical trial, a study of 10 people who saw the palmetto extract.
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Prognosis
Psychological
Androgenic alopecia is usually experienced as "a quite stressful condition that diminishes body image satisfaction". However, although most men consider baldness as an unwanted and distressing experience, they are usually able to overcome and maintain the integrity of the personality.
Although baldness is not common in women as in men, the psychological effects of hair loss tend to be much greater. Usually, the frontal hair line is maintained, but the hair density decreases in all areas of the scalp. Previously, believed to be caused by testosterone as well as in male baldness, but most women who lose hair have normal testosterone levels.
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Epidemiology
Female androgenic alopecia has been a growing problem, according to the American Academy of Dermatology, affecting about 30 million women in the United States. Although hair loss in women usually occurs after the age of 50 or even later when not following events such as pregnancy, chronic diseases, diet crashes, and stress, among others, now occurs at an early age with cases reported in women as young as 15 or 16.
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Society and culture
Studies have been inconsistent and unstable across cultures of how balding men rate on a tourist attraction scale. While a study from South Korea showed most people rated bald men as less attractive, a more recent survey of 1,000 Welsh women who were considered bald and gray-haired men were quite desirable.
The proposed social theories for male pattern hair loss include that baldness indicates dominance, social status, or longevity. Biologists have predicted that exposed areas of sunlight will allow more synthesized vitamin D, which may be a "mechanism set to prevent prostate cancer," because the malignancy itself is also associated with higher levels of DHT.
Myth
Many myths are given about the possible causes of baldness and its relationship to one's virility, intelligence, ethnicity, occupation, social class, wealth, etc. While skepticism may be justified in many cases due to lack of scientific validation, some claims may have an underlying and supported underlying level of truth.
There is a 50% chance for someone to share the same X chromosome with their maternal grandfather. Because women have two X chromosomes, they have two copies of the androgen receptor gene, whereas men have only one.
Because of the increase in testosterone levels, many Internet forums have put forward the idea that weight training and other forms of exercise increase hair loss in tended individuals. Although scientific studies support the relationship between exercise and testosterone, no direct study has found a link between exercise and baldness. However, some people have found a link between inactive life and baldness, suggesting some useful exercise. The type or amount of exercise can affect hair loss. Testosterone levels are not a good marker of baldness, and many studies actually show low paradoxical testosterone in bald people, although research on its implications is limited.
Emotional stress has been shown to speed baldness in genetically susceptible individuals. Stress due to lack of sleep in military recruits lowers testosterone levels, but not recorded has affected SHBG. Thus, stress due to lack of sleep in fit men is unlikely to increase DHT, which is one of the causes of male baldness. Whether sleep deprivation can cause hair loss by some other mechanism is unclear.
Free testosterone levels are strongly associated with libido and DHT levels, but unless free testosterone is virtually absent, levels have not been shown to affect virility. Men with androgenic alopecia are more likely to have higher base androgens. However, sexual activity is multifactoral, and the androgenic profile is not the only determinant factor in baldness. Moreover, since hair loss is progressive and decreases in free testosterone with age, male hairline may show more of its past than current disposition.
Many misconceptions about what may help prevent hair loss, one of which is that lack of sexual activity will automatically prevent hair loss. While direct correlations proved to exist between increased frequency of ejaculation and increased levels of DHT, as demonstrated in a recent study by Harvard Medical School, this study suggests that the frequency of ejaculation may be a sign, not a cause, a higher level of DHT. Other studies have shown that although sexual arousal and orgasm induced by masturbation increase testosterone concentrations around orgasm, they decrease the average concentration of testosterone (especially before abstinence) and since about 5% of testosterone is converted to DHT, ejaculation does not increase the level of DHT.
The only published study to test the correlation between ejaculatory frequency and baldness may be large enough to detect an association (1390 subjects) and find no correlation, although people with only vertex androgenetic alopecia have fewer female sexual partners compared to the androgenetic alopecia category others (such as frontal or both frontal and vertex). One study may not be enough, especially in baldness, where there is a complex with age. Marital status has been shown in several studies to influence hair loss in a cross-sectional study (NHANES1), although the direction of the effect can not be inferred from a cross sectional study.
Name
Male hair loss patterns are also known as androgenic alopecia, androgenetic alopecia (AGA), alopecia androgenetica and male pattern baldness (MPB).
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Other animals
The animal model of androgenic alopecia occurs naturally and has been developed in transgenic mice; chimpanzee ( Pan troglodytes ); bald uakaris ( Cacajao rubicundus ); and flaky tailed apes ( Macaca speciosa and M. arctoides ). Of these, monkeys have shown the greatest incidence and the most prevalent hair loss rate.
Baldness is not a unique trait for humans. One possible case study was the lion Tsavo an uncivil man. The lions' Tsavo lions are unique because they often only have a single male lion with usually seven or eight adult females, compared to four females in other lions. Tsavo males may have high testosterone levels, which may explain their reputation for aggression and dominance, suggesting that the deficiency of the mane at any given time has had an alpha correlation.
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References
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External links
- NLM- Genetic Home Reference
- Scow, D. T.; Nolte, R. S.; Shaughnessy, A. F. (1999). "Medical treatment for balding in men". American Family Doctor . 59 (8): 2189-2194, 2196. PMID 10221304.
Source of the article : Wikipedia
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