Psoriasis is a chronic inflammatory skin disease that causes red scaly patches to appear on the skin. It occurs when skin cells multiply up to 10 times faster than normal. The two main types are plaque psoriasis, which causes raised, red patches covered with silvery scales, and guttate psoriasis, which appears as numerous small spots. Psoriasis has no cure but can be managed with topical creams and ointments, phototherapy, or systemic medications.