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.

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.

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.

Hair loss should be expected to be permanent.

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.

Minoxidil is a lotion, now available over-the-counter. It is applied to the scalp twice daily. It prevents further hair loss in most people within two months of starting treatment. Within four to eight months, about 30 percent of people grow new hair that is long enough to be cut or combed. Success is greatest in younger people who have just begun to lose hair. Women appear to respond to minoxidil just as well as men do. Better success generally is seen with a higher strength (5-percent) solution. One caution: If you stop using minoxidil, you probably will lose all the hair that was retained or restored by the medication.

Finasteride is a prescription-only pill that blocks the formation of the type of testosterone that affects hair growth. Higher strengths of the same medication are used in men to stop non-cancerous (benign) growth of the prostate gland. Studies suggest that finasteride helps to prevent hair loss in up to 99 percent of men with hereditary-patterned baldness, and that two-thirds experience some new hair growth. As with minoxidil, any benefits from the medication are quickly lost once it is discontinued. In addition, a small number of men develop difficulty with sexual function.

Finasteride does not appear to prevent hair loss in women. It also may cause birth defects, and should not be used by any woman who could possibly get pregnant. However, other types of hormonal treatment (such as certain types of birth control pills) may help the minority of women with hair loss who have elevated levels of male hormones.

In some people, hair loss may be caused by certain hair treatments (straightening, coloring), hairstyles (tight braids) or hair pulling. Although these are not factors in most cases of hereditary-patterned baldness, they may contribute to hair loss and should certainly be discontinued.

A variety of other creams, oils, lotions and herbal remedies for hair loss are regularly advertised. However, only minoxidil and finasteride have been proven effective.

Some over-the-counter scalp treatments can cause irritation or harm and worsen hair loss.

Minoxidil and finasteride can promote new hair growth in addition to preventing hair loss. This effect is quite unpredictable from one person to the next.

Hair weaves, wigs and toupees can be used. In addition, a variety of surgical techniques also can be used, including:

• Scalp reduction — Strips of bald skin are removed surgically to decrease the size of a bald spot.
• Hair flaps — A strip of skin with good hair growth can be moved from a less cosmetically important area to a more important one.
• Hair transplants — Tiny plugs of skin containing from one to 15 hairs are moved from the back or side of the scalp to a bald area. The newer “micrografts,” which contain very few hairs, yield the best results, but are more expensive and time consuming than older types of transplants. Up to 700 individual grafts may be necessary to complete a treatment. It may take up to two years to see the full benefit of hair replacement surgery.

Call a health care professional if you have any of the following symptoms; they can suggest a problem other than hereditary-patterned baldness:

• Hair that falls out suddenly or in clumps
• Patchy hair loss (“flea bitten” appearance)
• Redness, flaking or scarring of the scalp in the area of hair loss
• Hair loss in women under age 30
• Signs of abnormally high testosterone levels in women, including abnormal menstrual periods, deepening of the voice, acne, hair loss in a male pattern or hair growth in unusual places (face, chest)

Most doctors or dermatologists will prescribe finasteride to men who would like to use it. If you are interested in cosmetic surgery, consult a cosmetic surgeon or dermatologist who specializes in hair restoration.

Unless a preventive treatment is started, hereditary hair loss becomes more pronounced over time. Generally, the earlier hair loss begins, the more severe it will become. Preventive treatment with minoxidil or finasteride must be continued indefinitely to maintain results.

Diseases and Conditions Center

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.