Psoriasis is an autoimmune condition that causes cells to build up speedily on the surface of the skin. The extra skin cells form scales and red patches are often associated with itching and flaking. Psoriasis symptoms usually occur on the scalp, elbows, knees, and lower back and genitals, but they can appear anywhere. Psoriasis can also affect the fingernails.

Psoriasis disease is not contagious and does not spread from person to person. In most people, the rash is limited to a few patches of skin. In severe cases, it can cover large areas of the body.

The main goal of psoriasis treatment should therefore be to stop the skin cells from growing so quickly.