In Medical Terms: Androgenetic Alopecia
Female pattern hair loss (FPHL) differs from male pattern hair loss (MPHL) in the following ways:
- It is more likely to be noticed later than in men, in the late twenties through early forties.
- It is likely to be seen at times of hormonal change, i.e., use of birth control pills, after childbirth, around the time of menopause, and after menopause.
- Recession at the temples is less likely than in men and women tend to maintain the position of their hairlines.
- Like in men, the entire top of the scalp is the area of risk.
- In women there is generally a diffuse thinning throughout the area as opposed to thinning in the crown of men. Ludwig has classified hair loss in women into three classes. The vast majority of women affected fall into the Ludwig I class.
In the United States it is estimated that 21 million women are affected by FPHL. The incidence in women has been reported to be as low as eight percent and as high as 87 percent. It does appear to be as common in women as in men. The hair loss in women becomes particularly notable in menopause.
Androgens are responsible for hair loss in women by the same mechanisms they cause hair loss in men. Women do produce small amounts of androgens by way of the ovaries and adrenal glands. Also prehormones are produced by the ovaries that are converted to androgens outside of the ovaries or adrenal glands. Women rarely experience total loss of hair in an area if the loss is due to FPHL. If they do they should be evaluated for an underlying pathological (disease) condition. In women, the process of miniaturization of the hair follicle is more random with some hair being unaffected. Normal thick hairs are mixed with finer, smaller diameter hairs. The end result is a visual decrease in density of hair rather than total loss of hair. The hair growth cycle is affected as in men. The growth phase (anagen) is shortened resulting in shorter hairs and the resting phase (telogen) is increased resulting in fewer hairs.
If the cause of hair loss is suspected to be abnormally elevated or decreased amounts of hormones the patient should undergo laboratory tests to measure hormone levels.
©1999, Bradley R. Wolf, M.D.