Psoriasis is a chronic inflammatory skin disorder with intermittent flares and clearing that affects about 2% of the population. Psoriasis is an uncomfortable and occasionally disabling disease, with a _ social and economic impact that is often underestimated by medical personnel. Psoriasis has several clinical phenotypes including guttate, pustular, and arthritic variants. This review focuses mainly on the most common form, chronic plaque psoriasis.