Psoriasis (say "suh-RY-uh-sus") is a long-term (chronic) skin problem that causes skin cells to grow too quickly and form thick, white, silvery, or red patches. They're most often found on the knees, elbows, scalp, tailbone, and back.

Psoriasis isn't contagious. It tends to run in families. There are many types of treatment that can help keep it under control.