Baldness is also called ALOPECIA, the lack or loss of hair.Two primary types of baldness cun be distinguished: permanent hair loss arising from the destruction of hair follicles, and temporary hair loss arising from transitory damage to the follicles. The first category is dominated by male -pattern baldness, which occurs to some degree in as much as 40 percent of some male populations. The hair loss in male - pattern baldness progresses gradually, beginning with a

characteristic recession of the hairline at the front or thinning of the crown hair and proceeding, in extreme cases, until only a thin rim of hair remains at the sides and back of the head.

Male -pattern baldness has a hereditary basis; it varies in degree and seems to be caused by imbalances in the level of male hormones (testosterone and androgens) circulating in the blood. Male - pattern baldness is ususlly seen in persons with origins in the European and Australian geographic races. In Australian aborigines it is often accompanied by calvities of the legs. It is rare among Asians, American Indians, and Africans. Other causes of permanent baldness include many scar - producing skin diseases and injuries, inbon lack of hair development, and severe injury to hair follicles by chernical or physical agents.

A temporary loss of hair occurs fairly commonly after conditions accompanied by high fever but may also by produced by X -rays, ingestion of metals(such as thallium, fin, and arsenic) or drugs, malnutrition, some inflammatory skin disease, chronic wasting discaes, and endocrine disorders. Alopecia areata, a fairly common disorder of unknown cause characterized by sharply outlined patches of sudden complete baldness, is also usually temporагу.

There are two medical treatments for male - pattern baldness. The first, hair transplantation, involves the transplanting of hair follicle from areas of the scalp where hair is still growing to areas where it is not--e. g., from the back to the front of the head. The second treatment consists of the topical application of drugs. One drug, minoxidil, when applied to the scalp on a daily basis, is thought to be effective in preventing further hair loss in many cases and in growing new hair on bald or thinning areas in a much saller proportion of cases.

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