The Facts
About 3% of the population has the chronic skin condition called psoriasis. Five to fifteen percent of these people also suffer from inflammation, pain, or disability in the joints. When this is the case, they have psoriatic arthritis, a joint disease related to psoriasis.
Psoriatic arthritis typically appears when people are between the ages of 20 and 50, and is equally common in men and women. For about 80% of people with psoriatic arthritis joint problems developed some months or years after the first skin symptoms appeared. But in about 15% of the cases, the arthritis appears before the psoriasis. Over 80% psoriasis sufferers notice changes in the toenails or fingernails.