Alopecia areata
Alopecia areata, also known as spot baldness, is a condition in which hair is lost from some or all areas of the body. Often, it results in a few bald spots on the scalp, each about the size of a coin. The disease may cause psychological stress. People are generally otherwise healthy. In a few cases, all the hair on the scalp is lost, or all body hair is lost, and loss can be permanent.
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