Psoriasis

Psoriasis is a chronic (long-lasting) disease that affects the skin. Scaling and inflammation of the skin are typical of the disease. Scaling occurs when cells in the outer layer of skin reproduce faster than normal and pile up on the skin's surface. Psoriasis is not contagious. People with psoriasis may have discomfort, including pain and itching, restricted motion in their joints, and emotional distress. The National Psoriasis Foundation estimates that psoriasis affects about 5.5 million people in the United States. The disease affects mostly adults and occurs about equally in men and women. In its most common form, psoriasis results in patches of thick, red skin covered with silvery scales. These patches, sometimes called plaques or lesions, usually itch and may burn. The skin at the joints may crack. Psoriasis most often affects the elbows, knees, scalp, lower back, face, palms, and soles of the feet, but it can affect any skin site. The disease may also affect the fingernails, the toenails, and other tissues. Some people with psoriasis also have joint inflammation that produces arthritis symptoms. This condition is called psoriatic arthritis.