a review of female pattern hair loss
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A review of female pattern hair loss

Doctor Vera H. Price, at the Department of Dermatology at the University of California San Francisco, conducted a review of female pattern hair loss and its diagnosis based on her own research and medical journal publications by other dermatologists and scientists.

Androgenetice alopecia (AGA) in women is also known as female pattern hair loss or female pattern baldness. AGA in women is similar to AGA (male pattern baldness) in men. AGA is surprisingly common in women with up to 40% of women affected at some point in their lives. In spite of its prevalence, many clinicians and clinical investigators have difficulty making the diagnosis in women. Studies by scientists Hamilton and Trancik found that it can begin as early as 12 years or or as late as 40 in either sex. Other studies found that nearly half of the population experiences some degree of this hair loss condition before the age of 50. It can be an inherited from either one, or both sides of the family. These studies were done by Venning, Dawber, Olsen, Kuster, Happle, and Sreekumar.

Both women and men with AGA can have increased levels of dihydrotestosterone (DHT). It is thought that DHT is responsible for the miniaturization of hair follicles in found in patients with AGA. In genetically susceptible hair follicles, DHT binds to the hormone-receptor complex on hair follicle cells and activates the genes responsible for the gradual transformation of large, terminal follicles to miniaturized follicles. While the number of follicles in an area remains the same, they are miniaturized in two ways; the growth-stage of the hair follicle is much shorter than normal and the hair follicles are much smaller than normal terminal scalp hair follicles. Consequently, the miniaturized hair follicles produce thinner and shorter hair fibers than they should. In women with AGA, the extent of hair loss is generally less than in men. This discovery was the result of several studies by Price, Uno, Messenger, and Kaufman.

It has commonly been assumed that the hormonal basis for AGA is similar in women as in men although earlier studies did not include female subjects and focused exclusively on men. In order to compare and clarify the underlying hormonal basis in women as compared to men, a study was conducted among 24 people with AGA: 12 women between the ages of 14 and 33 and 12 men between the ages of 18 and 30. The study measured a variety of factors in the subjects’ scalp skin and hair follicles and found that both genders had higher levels of “5a-reductase and androgen receptors” in the hair follicles toward the front of their head compared to the hair follicles around the back of their head. However the women only had about half of the level found in the men. Meanwhile, the women had higher levels of “cytochrome p-450 aromatase” in the follicles in the front of their scalp. Aromatase can convert testosterone into estradiol. Overall, this study indicated that women experience a lower level of AGA than men due possibly in part by the lower levels of 5a reductase in the frontal follicles compared to men, and that the higher levels of aromatase in women creates more estradiol in women than men… and less 5a reduced products, like DHT.

What does this mean? It seems that; 1) AGA hair loss is actually the minimization of hair. 2) DHT is linked to the cause of the minimization of hair. 3) 5a –reductase creates DHT. 4) Men have more 5a-reductase than women. 5) Women have some 5a-reductase but the increased presence of aromatase in the skin and hair follicles takes testosterone and converts it to estradiol so overall there is less DHT in the skin of women. Because of this advantage, women may be less likely to suffer from AGA than men.

While not necessarily discovered in this study, Price adds the results of this study to the ongoing study of hair loss in many clinics and laboratories and lists some other conclusions in the field:

• even though women experience hair loss, it is not as widespread across the scalp as in men.
• The front and top of the scalp experience more thinning then the back. In fact, the back of the scalp has the greatest hair density.
• It is possible that in the embryonic stage of development, the top of the scalp and the back of the scalp develop from different points. This is also true in birds, as found in a study by Ziller. In fact, cell growth and cellular interaction may influence the hair follicles differently in the two regions because of their different origin.
• Women first notice their hair thinning over the front region of the scalp and over time the scalp becomes more visible as the hair loss moves to the top of the scalp. Generally, women do retain a rim of hair along the front of the hairline and hair loss starts behind the rim.
• Although hair density is the same, the new hairs are shorter and thinner.
• AGA in women is usually not accompanied with any increase in the rate of shedding of the hair.

The diagnosis of AGA in women is supported by the appearance of baldness at an early age and the pattern of increased hair thinning over the front and top of the scalp. She notes that one should be aware that while AGA is common, there may be other causes of hair loss as well that need to be taken into consideration. A careful history will usually identify the cause of profuse hair shedding such as high fever, severe dietary protein
deficiency, chronic blood loss, or drug use.

Dr Price suggests topical minoxidil solution is the only approved drug available for promoting hair growth in women with AGA. Its usefulness has been demonstrated in controlled studies using hair counts and hair weight as the primary measurements. In Dr Price’s own evaluation studies, minoxidil-treated women had significantly higher hair counts and an increase in hair weight compared to women who received placebo.


A review of female pattern hair loss references

  • Price VH. Androgenetic alopecia in women. J Investig Dermatol Symp Proc. 2003 Jun;8(1):24-7. PMID: 12894991
  • Price VH, Menefee E. Quantitative estimation of hair growth. I. androgenetic alopecia in women: effect of minoxidil. J Invest Dermatol. 1990 Dec;95(6):683-7. PMID: 2250110
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