Male pattern baldness
Alternative names
Alopecia in men; Baldness - male; Hair loss in men; Androgenic alopecia in men
Definition
Male pattern baldness describes a typical pattern of hair loss in men, caused by hormones and genetic predisposition.
Causes, incidence, and risk factors
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 there is a progressive miniaturization of the follicle, resulting in shorter and finer hair. The end result is a miniature follicle with no hair. The cause of the failure to grow a new hair is not well understood, but it is associated with a genetic predisposition and the presence of endocrine hormones (androgens, the male sex hormones), especially dihydrotestosterone, which is converted from testosterone. The follicles, however, remain alive, suggesting the possibility of new growth.
The typical pattern of male pattern baldness begins at the hairline. The hairline gradually recedes to form an "M" shape. The existing hair may be finer and does not grow as long as it did formerly. The hair at the crown also begins to thin, and eventually the top points of the hairline "M" meet the thinned crown, leaving a horseshoe pattern of hair around the sides of the head.
Hair loss in patches, diffuse shedding of hair, breaking of hair shafts, or hair loss associated with redness, scaling, pain, or rapid progression could be caused by other conditions.
Symptoms
thinning or absence hair
receding hairline (from the front toward the back over time)
thinning of hair
loss of hair at the crown of head
progression of hair loss in a typical "M"-shaped pattern
eventually results in a loss of hair over the top of the head
horseshoe ring shape of remaining hair
Signs and tests
Classic male pattern baldness is usually diagnosed based on the appearance and pattern of the loss of hair. Hair loss that occurs in an atypical manner may be caused by other medical disorders.
A skin biopsy or other procedures may be needed to diagnose other 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.
Treatment
The hair loss of male pattern baldness is permanent. No treatment is required if the person is comfortable with the appearance.
There are two drugs approved by the United States Food and Drug Administration (FDA) to treat male-pattern baldness: minoxidil and finasteride (Propecia).
Minoxidil is used topically on the scalp. It may help hair to grow in 20 to 25% of the population, and in the majority it may slow the loss of hair. Treatment is expensive, however, costing about $600 per year for the recommended twice-daily use. The higher concentration minoxidil works better. Hair loss recurs when its use is discontinued.
Finasteride is the only oral medication that is approved by FDA for male pattern baldness. It inhibits the production of the hormone that contributes to male pattern baldness. About 50% of men who take this drug have increased hair growth in one year. In general, it is more effective than minoxidil. It has no major effect on testosterone level in the body. About 2 percent of the men who take this drug experience sexual dysfunction.
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 the hair loss. This is usually the least expensive and safest treatment for male pattern baldness.
From MEDLINEPlus Medical Encyclopaedia.
