If you’ve seen a lot of extra hair on your pillow, brush, or shower drain, or you’ve noticed odd little bald spots in the mirror, you might have an autoimmune disorder called alopecia areata. This is an autoimmune disease. Your immune system attacks your own body particularly your hair follicles resulting in hair loss. This causes the hair to come out in small patches which can be unnoticeable and often in clumps the size and shape of a quarter. The amount of hair loss is different in everyone. Some people lose it only in a few spots. Others lose a lot. Sometimes hair grows back but falls out again later. In others, hair grows back for good.