It varies in severity from mild to severe. Psoriasis can affect the nails, scalp, skin and joints.
Psoriasis can start at any age.
When psoriasis involves the nails it usually causes pits in the nails as shown below. In psoriasis, areas of the skin grow much faster than normal and form red, scaling patches. The scalp, elbows, and knees are the most common sites for psoriasis, however any part of the skin may become involved. Psoriasis is a problem only because it itches and is unsightly. It is not contagious.