lopecia areata is an autoimmune disease that causes patchy hair loss anywhere on your body, but it most commonly affects the hair on the skin that covers your head (scalp). “Alopecia” is a medical term for hair loss or baldness, and “areata” means that it occurs in small, random areas.
WThere are many different classifications of alopecia areata. The classifications depend on the amount of hair you’ve lost and where you’ve lost it on your body.