question: Psoriasis (Summary): Psoriasis is a skin disease that causes itchy or sore patches of thick, red skin with silvery scales. The skin on the elbows, knees, scalp, back, face, palms and feet is most often affected, but other parts of the body can be affected as well. A problem with the immune system causes psoriasis. In a process called cell turnover, skin cells that grow deep in the skin rise to the surface. Normally, this takes a month. In psoriasis, it happens in just days because the cells rise too fast. Although symptoms may come and go, for many, psoriasis is a lifelong condition. Infections, stress, dry skin and certain medications may make symptoms worse. Psoriasis usually occurs in adults. It sometimes runs in families. Treatments include creams, medications and light therapy. [1] [2]