Hair loss is a growing problem that tends to affect both males and females equally. While the issue in males is somewhat depressing because hair loss in males is expected with increasing age, in females the effects can be catastrophic as it tends to affect their outlook and interpersonal and social relationships and can therefore be associated with profound depression. In this article we will try and look into the difference between these two entities from a hormonal point of view.
In the majority of males exhibiting baldness, the frontal hairline tends to recede therefore the forehead starts to widen. This can be associated with a patch of baldness appearing on the vertex which usually tends to increase with age and these two areas of recession often join together leading to the characteristic male pattern baldness or hair loss (MPHL).
The situation is quite different in females in whom the frontal hairline is usually preserved and there is thinning in the mid-frontal scalp akin to a Christmas tree. Along with this, there is a diffuse thinning of hair in the whole of the scalp which increases with age. Bitemporal recession which leads to increased angulations as is seen in male pattern baldness is quite rare in women. This is the characteristic female pattern hair loss (FPHL) although variations can occur.
Despite these differences, the histological pattern of hair loss is similar in both males and females. This involves a gradual thinning of hairs from the terminal state to a vellus state and the hair is then shed off. Also, the proportion of hairs that are in the anagen or growth phase is also decreased therefore hair growth also tends to be less.
The essential incriminator in hair loss is the androgen receptor which initiates miniaturization once the androgen binds to it especially DHT (Dihydrotestosterone) which is a derivative of testosterone and is much potent than it when it comes to its effect on the hairs. Free testosterone is quite less in women and therefore the central effect of the androgens in FPHL is possibly much less in women. This also makes the degree of hair loss less severe in women. Women also have higher levels of a hormone aromatase which converts circulating testosterone to estrogen therefore limiting its effect on the hairs. However, on the other hand, abnormal aromatase leading to increased estrogen can also lead to FPHL therefore making the pathogenesis totally unclear! At the same time, the prevalence of androgen receptors in the scalp of women in less limiting the effect of androgens and also the aromatase level in the frontal area of women is more compared to males thereby leading to preservation of the frontal hairline in women.
Although the cardinal pathogenesis of hair loss in males and females is similar, the difference in patterns and hormones dictates that management is different in these two categories in patients.