Incidence of Female Androgenetic Alopecia (Female Pattern Alopecia)

O’Tar T. Norwood, MD
Norwood & Lehr: Hair Transplant Clinic, Oklahoma City, Oklahoma
Source: Dermatologic Surgery Volume 27 Number 1 January 2001

Background. Female pattern alopecia seems to be increasing. A recent article suggests that female androgenetic alopecia may not be androgen dependent and is a different ages of female androgenetic alopecia in 1000 Caucasian woman 20 years of age and older.

Objective. To determine the incidence at different ages of female androgenetic alopecia in 1000 Caucasian women 20 years of age and older.

Methods. A total of 1006 Caucasian women were examined for the presence of female androgenetic alopecia.

Conclusion. Female androgenetic alopecia is quite common beginning in the late 20s and reaching its peak after 50 years of age.

Female Androgenetic alopecia seems to be on the increase.¹ A recent article² by the author presented evidence that female androgenetic alopecia is not the female counterpart of male androgenetic alopecia. Furthermore, it is suggested that female androgenetic alopecia is not androgen dependent. The purpose of this article is to determine the incidence of female androgenetic alopecia and its occurrence at different ages in 1006 Caucasian women. Female androgenetic alopecia is here after referred to female pattern alopecia.

Method
One thousand eight Caucasian females were examined. The women were from a dermatology practice, a retirement center, clinic and hospital staff members, various doctors’ waiting rooms, and beauty shops. Any person visiting the doctor for hair loss was excluded to avoid bias in the study. Each subject was simply asked their age and then their scalp was examined.

Results
Female pattern alopecia is quite common, beginning in the late 20s and reaching almost 30% in women over 30 years of age (see Table 1).

Comment
While doing this study, two unexpected observations were noted. First, in Ludwig’s³ original description of female pattern alopecia, he described hair loss just behind the hairline. He stated that the hairline maintained its density. We found this to be more or less true, but in many instances the hairline lost much of its density but remained more dense than the hair directly behind it.

Second, as we examined these individuals, we noted a large number of women had what is best described as early type II male androgenetic alopecia (see Figure 1). This was characterized by a decrease in the density of the hair and a decrease in the caliber of the hair at the temples and at the temple points. This closely resembled typical type II male androgenetic alopecia. Although the numbers were not tabulated, it was a common observation. An article by Venning,⁴ described this and found that it occurred in 37% of the women he examined. His point was that this early male androgenetic alopecia in females was not necessarily associated with high levels of testosterone. Our study confirms this view. None of these women had any evidence of excess testosterone.

The question remains as to why dermatologists have so long thought that female pattern alopecia was the female counterpart of male androgenetic alopecia. It probably began with Ludwig’s³ initial description and his assumption that male androgenetic alopecia and female androgenetic alopecia were the same disease and that both were due to androgens (Messenger A, personal communication).³

In a previous article, the author² presented the following arguments for separating male androgenetic alopecia from female pattern alopecia:

Male pattern baldness begins with recession of the hairline and results in complete hair loss. Female pattern alopecia causes diffuse thinning of the hair at and behind the hairline, but there is no recession of the hairline.

Male pattern baldness affects up to 70% of all males in later life. Female androgenetic alopecia affects up to 30% of older women. If these were the same diseases, the incidence should be nearly the same.

Women with genetic predisposition for male androgenetic alopecia will develop typical male androgenetic alopecia if given high doses of testosterone. Some men develop typical female pattern alopecia.

This study further supports the notion that these are separate diseases by finding that female pattern alopecia begins in the late 20s and peaks after 50 years of age when testosterone levels are falling. This is in contrast to male androgenetic alopecia which begins in the late teens and early 20s when testosterone levels are high.

References:

Figure 1. Two young women with miniaturization and decreasing density at the temple and temple points. This is best described as type male androgenetic alopecia. This was commonly found in young women.