Psoriasis is a common skin condition that causes skin redness and irritation. Most persons with psoriasis have thick, red skin with flaky, silver-white patches called scales.Psoriasis is a very common condition. The disorder may affect people of any age, but it most commonly begins between ages 15 and 35. It can appear suddenly or slowly. In many cases, psoriasis goes away and then flares up again repeatedly over time. The condition is not contagious. Psoriasis seems to be an inherited disorder. That means it is passed down through families. Doctors think it probably occurs when the body's immune system mistakes healthy cells for dangerous substances. Skin cells grow deep in the skin and normally rise to the surface about once a month. In persons with psoriasis, this process is too fast and dead skin cells build up on the skin's surface.
