Alopecia is an autoimmune disease where the main and usually the only symptom is hair loss. There are many different forms that cause hair loss from small patches, such as alopecia areata, to full body hair loss, such as alopecia areata universalis. Unfortunately there is no cure for alopecia and the amount of hair loss is different in everyone. With alopecia areata, it’s the hair follicles that are attacked. Doctors don’t know why it happens. But they think people who get it have something in their genes that makes it more likely. Then something happens to trigger the hair loss. With alopecia it is possible for the hair to grow back, but the hair loss may then occur elsewhere on the scalp, face or body.