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 spot on the scalp, each about the size of a coin.  psychlogical stress and illness are possible factors in bringing on alopecia areata in individuals at risk, but in most cases there is no obvious trigger.People are generally otherwise healthy.In a few cases, all the hair on the scalp is lost (alopecia totalis), or all body hair is lost (alopecia universalis). Hair loss can be permanent, or temporary. It is distinct from pattern hair loss, which is common among males.

Alopecia areata is believed to be an auto immune disease resulting from a breach in the immune privilegeof the hair follicles.Risk factors include a family history of the condition.Among identical twins , if one is affected, the other has about a 50% chance of also being affected.The underlying mechanism involves failure by the body to recognize its own cells, with subsequent immune-mediated destruction of the hair follicles.

No cure for the condition is known.Some treatments, particularly triamcinolone injections and 5% minoxidil topical creams and shampoo,are effective in speeding hair regrowth.