Men who experience male pattern alopecia have a characteristic receding hairline and hair loss on the top part of the head. People with this condition typically retain the hair on the sides of their heads.
Genetics determines who will develop male pattern baldness and who will not. Those who do develop this condition have a sensitivity to DHT, dihydrotestosterone. This substance causes the hair follicles to shrink and shortens the growth phase of the hair cycle. As a result, the hair starts to thin. An enzyme called 5-alpha reductase controls the production of dihydrotestosterone, which is found in the scalp and other body tissues. When 5-alpha-reductase speeds up the production of DHT, those who have a sensitivity to it experience hair thinning and hair loss.
Male pattern alopecia is more than just a minor cosmetic flaw. This condition is actually associated with depression, low self-esteem, feelings of unattractiveness and introversion in some men. Because many people place a great importance on looking young and attractive, men with this condition may feel less likable and less successful than those who have not lost their hair.
Those with this condition have several treatment options, including medications, hairpieces and hair transplantation. Medications used to treat this problem include dutasteride, finasteride and minoxidil. Dutasteride acts as a 5-alpha-reductase inhibitor, which reduces the production of DHT. The side effects of this drug include decreased sex drive, breast enlargement, impotence and decreased semen release during sexual intercourse. Finasteride also inhibits the action of 5-alpha-reductase and slows down the production of dihydrotestosterone. It has side effects similar to those of dutasteride since they work the same way. Minoxidil increases hair growth, but scientists do not know exactly what causes this additional hair growth. Side effects of minoxidil, sold under the brand name Rogaine, include itching and irritation, allergic reaction and dry scalp.
During hair transplant surgery, a physician removes hair from the sides or back of the scalp to the thinning and bald areas at the front of the scalp. Doctors who perform this procedure refer to the hair at the back and sides of the head as the “donor area” and the area at the front of the head as the “recipient area.” The physician doing the transplant harvests tiny bundles of hairs using the follicular unit transplantation or follicular unit extraction method. The physician then inserts these hairs into small needle-sized holes at the front of the head. In two to three months, the transplanted units begin producing new hair, and the new hair matures after approximately one year. Physicians can use the same type of procedure to replace lost hair in the eyebrows.
DermNet NZ: Male Pattern Hair Loss
Drugs.com: Dutasteride Medical Facts
Drugs.com: Finasteride Official FDA Information, Side Effects and Uses
MedicineNet: Minoxidil (Rogaine)
Bernstein Medical Center for Hair Restoration: Hair Transplant Surgery