Psoriasis (sore-I-ah-sis) is a common immune-mediated chronic skin disease that comes in different forms and varying levels of severity. Most researchers now conclude that it is related to the immune system (psoriasis is often called an "immune-mediated" disorder).
It is not contagious. In general, it is a condition that is
frequently found on the knees, elbows, scalp, hands, feet or lower back. Many treatments are available to help manage its symptoms. More than
4.5 million adults in the
United States have it.
It
generally appears as patches of raised red skin covered by a flaky white buildup. In certain kinds of psoriasis, it also has a pimple-ish (pustular psoriasis) or burned (erythrodermic) appearance.
Between 10 percent and 30 percent of people with psoriasis also develop a related form of arthritis, called psoriatic (sore-ee-AA-tic) arthritis.