A physician makes the diagnosis after observing the skin, and studying the psoriatic plaque cells under a microscope. Pitting of the nails can be a sign of psoriasis. There is no medical test for psoriasis. There are various forms of psoriasis. Plaque psoriasis is the most common.
Psoriasis can range from mild to moderate to very severe and disabling.
Psoriasis is not contagious. Psoriasis most commonly appears on the scalp, knees, elbows, hands and feet. It rarely affects the face. However, no area of the skin is exempt, including the genital area. It is not possible to predict who will get psoriasis.