Hereditary-Patterned Baldness

What Is It?

Hereditary-patterned baldness — or androgenetic alopecia — is the most common cause of hair loss, affecting 30 percent to 40 percent of both men and women. Hereditary-patterned baldness is not really a disease, but a natural condition caused by some combination of genetics, hormone levels and the aging process. Hair loss typically begins in the 20s and 30s, although in women the changes are most noticeable after menopause.

In recent years, researchers have begun to understand more about the cause of this type of hair loss. Under the influence of a form of the male hormone testosterone, there is a change in the normal cycle of hair growth, resulting in shorter, thinner or "miniaturized" hair. Eventually, hair growth in certain parts of the scalp stops entirely, which produces the typical pattern of hair loss. Contrary to the folk wisdom that baldness is inherited from one's mother's family, genes contributed by both parents appear to affect hormone levels as well as the general susceptibility to this process.

Symptoms

Hereditary-patterned baldness starts with thinning of the hair and progresses to complete hair loss in parts of the scalp. Hairs on the pillow, in the tub or on the comb are unreliable symptoms of hair loss. The average non-balding person loses 100 hairs per day, and more hair may fall out under certain circumstances, such as after childbirth or a serious illness.

In men, hair loss typically begins at the temples and crown and proceeds in an M-shaped pattern. In the most advanced stage, only a rim of hair along the side and back of the scalp remains.

In women, hair loss tends to be more widespread but better camouflaged. The top of the head down the middle is most commonly affected, often in a "Christmas tree" pattern. In contrast to men, the hairline along the forehead and temples usually remains normal in women. Complete loss of hair in any one place on the scalp is unusual and may suggest that a different process is at work, such as alopecia areata (an immune system disorder that causes bald patches), a fungus infection or one of a number of skin conditions.

Diagnosis

Hereditary-patterned baldness usually is diagnosed by both its pattern and a history of a similar type of hair loss affecting family members. In most people, no further tests are required.

Expected Duration

Hair loss should be expected to be permanent.

Prevention

If you begin to lose hair in a hereditary pattern, you may be able to prevent further hair loss by using minoxidil (Rogaine) or finasteride (Proscar). Minoxidil can be used by both men and women, while finasteride usually is used just for men.