Alopecia areata

In alopecia areata, the immune system affects the hair follicles, which stop producing hair for a time. The follicles are not destroyed, which is why hair can regrow, although the course is hard to predict and patches can come and go.

It typically appears as one or more smooth, round bald patches that develop quickly. Some people notice short broken hairs at the edges of a patch. Less commonly it affects larger areas of the scalp or body hair, including eyebrows and eyelashes.

Anyone with sudden patchy hair loss, and any child with hair loss, should see a GP. A GP can confirm what is happening and refer to a dermatologist where appropriate. Support from others who have been through it can also help, as the emotional impact is often significant.