Female-pattern baldness

Alternative names:

alopecia in women; androgenic alopecia in women; baldness - female; hair loss in women

Definition:

A typical pattern of loss of hair in women caused by hormones, aging, and genetic predisposition.

Causes, incidence, and risk factors:

Hair grows from the hair follicle at an average rate of a 1/2 inch per month. Each hair grows for 2 to 6 years, then rests, and finally falls out. A new hair then begins growing in its place. At any one time, about 85% of the hair is growing and 15% is resting.

Baldness occurs when the hair falls out but a new hair does not grow in its place. The cause of the failure to grow a new hair is not well understood, but it is associated with genetic predisposition, aging, and levels of endocrine hormones (androgens). Changes in the levels of the androgens can affect hair production. For example, after the hormonal changes of menopause, many women find that the hair on the head is thinned, while facial hair is coarser. Although new hair is not produced, the follicle remains alive, suggesting the possibility of new hair growth.

The typical pattern of female-pattern baldness is different than that of male-pattern baldness. The hair thins all over the head, but the frontal hairline is maintained. There may be a moderate loss of hair on the crown, but this rarely progresses to total or near baldness as it may in men.

Hair loss can occur in women for reasons other than female-pattern baldness. These may include temporary shedding of hair (telogen effluvium), breaking of hair (from such things as styling treatments, and twisting or pulling of hair), patchy areas of total hair loss (alopecia areata--an immune disorder causing temporary hair loss), oral medications, as well as certain skin diseases.