When someone has psoriasis , new skin cells move rapidly to the surface of the skin in days rather than weeks and build up and form thick patches. These patches range in size from small to large and are most often seen on the knees, elbows, scalp, hands, feet, or lower back of your body.
Having psoriasis can be embarrassing, and many people, especially teens, avoid swimming and other situations where patches can show. But there are many types of treatment that can help keep psoriasis under control. Experts believe that psoriasis occurs when the immune system overreacts, causing inflammation and flaking of skin and can also run in families.