Scalp psoriasis (sore-eye-uh-sis) is a long-lasting (chronic) autoimmune disease (caused by your own immune system) that causes your skin cells to reproduce too quickly. It creates thick, discolored patches of skin (plaques) on your scalp and other areas around your scalp. These areas may include: Your hairline. Your forehead. The back of your neck. The skin around your ears.