Psoriasis

is a common condition. A person with psoriasis generally has patches of raised red skin with silvery scales. The affected skin may look shiny and red or even have pustules, depending on the type of psoriasis the individual has. These skin changes usually occur on the elbows, knees, scalp, and trunk. In the United States, about 7 million people (2-3% of people) have psoriasis. About 150,000-260,000 new cases are diagnosed each year. Psoriasis can also affect the fingernails and toenails.
 
Most people who have psoriasis of the nails also have skin psoriasis (also called cutaneous psoriasis or just psoriasis). Only 5% of people with psoriasis of the nails do not have skin psoriasis. In people who have skin psoriasis, 10-55% have psoriasis of the nails (also called psoriatic nail disease). About 10-20% of people who have skin psoriasis also have psoriatic arthritis, a specific condition in which people have symptoms of both arthritis and psoriasis. Of people with psoriatic arthritis, 53-86% have affected nails.
 
If psoriasis of the nails is severe and is not treated, it can lead to functional and social problems.