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

Baldness occurs when hair falls out but new hair does not grow in its place. The cause of the failure to grow new hair in female pattern baldness is not well understood, but it is associated with genetic predisposition, aging, and levels of endocrine hormones (particulary androgens, the male sex hormones).

Changes in the levels of 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, follicles remain 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), some medications, and certain skin diseases.

• thinning of hair over the entire head
• hair loss at the crown or hairline, mild to moderate

Female pattern baldness is usually diagnosed based on the appearance and pattern of hair loss and by ruling out other causes of hair loss.

A skin biopsy or other procedures may be used to diagnose medical disorders that cause loss of hair.

Hair analysis is not accurate for diagnosing nutritional or similar causes of hair loss. It may reveal substances such as arsenic or lead, however.

The hair loss of female pattern baldness is permanent. In most cases, it is mild to moderate. No treatment is required if the person is comfortable with her appearance.

The only drug or medication approved by the United States Food and Drug Administration (FDA) to treat female pattern baldness is minoxidil, used topically on the scalp. It may help hair to grow in 20% to 25% of the female population, and in the majority it may slow or stop the loss of hair. Treatment is expensive, however, costing about $600 per year for the recommended twice-daily use. For women, the 2% concentration is recommended. Hair loss recurs when minoxidil's use is stopped.

Hair transplants consist of removal of tiny plugs of hair from areas where the hair is continuing to grow and placing them in areas that are balding. This can cause minor scarring in the donor areas and carries a modest risk for skin infection. The procedure usually requires multiple transplantation sessions and may be expensive. Results, however, are often excellent and permanent.

Suturing of hair pieces to the scalp is not recommended as it can result in scars, infections, and abscess of the scalp. The use of hair implants made of artificial fibers was banned by the FDA because of the high rate of infection.

Hair weaving, hairpieces, or change of hairstyle may disguise hair loss and improve cosmetic appearance. This is often the least expensive and safest method of treating female pattern baldness.

Complications are psychological stress and a loss of self-esteem due to change in appearance.

Call your health care provider if hair loss occurs and persists. There might be a treatable medical cause for the loss of hair.

Also call your health care provider if female pattern baldness is present and you want to treat the hair loss; or if hair loss is accompanied by itching, skin irritation, or other symptoms.