An average condition, alopecia areata usually starts as a single, quarter-sized circle of perfectly smooth baldness. Alopecia patches usually regrow in three to six months without treatment. Sometimes, hair grows back in white. In another way, alopecia can produce two or three bald patches. When these grow back, others may replace them. The most extensive form is called alopecia totalis, in which the entire scalp goes bald. It's important to emphasize that patients who have localized hair loss generally don't go on to lose hair all over the scalp. Alopecia can affect hair on other parts of the body too - for instance the beard.

Alopecia areata is considered an autoimmune condition, in which the body attacks itself (in this case its own hair follicles). Most alopecia patients, however, do not have systemic problems and need no medical tests. Alopecia is also often blamed on "stress" but in fact it's usually the other way around: having alopecia causes the stress, at least until people find out what it is.

Treatments for alopecia areata include injecting steroids into affected patches to stimulate hair growth. This is not practical for large areas. Other treatments, such as oral steroids or ultraviolet light therapy, are either toxic or impractical. In most mild cases, patients can comb over the affected areas. In more severe and chronic cases, some patients wear hairpieces; nowadays some men shave their whole scalp, now that this look has become fashionable.