Psoriatic arthritis (PA) is an inflammatory autoimmune disorder that afflicts some people who have psoriasis, a common skin disease. Patients have pain and swelling in joints and thick, scaly patches on some parts of their skin.

The disease typically affects adults in their 30s through 50s, but children can develop a form of the disease called juvenile psoriatic arthritis.

PA can appear in five major forms, with symptoms ranging from mild to severe. Most people with PA develop psoriasis long before arthritic symptoms appear. Fingers and toes are the areas of the body most commonly affected. Many patients also experience pitted, discolored nails and inflammatory eye conditions.

In most patients, flare-ups of psoriasis and arthritis tend to come and go and at separate times.

People who have a parent or sibling with PA are themselves at greater risk for the disease. The condition is also associated with stress, reactions to medications or vaccines, illness and other factors.

There is no known cure for PA, but medication, physical therapy and lifestyle changes can often relieve pain and slow the disease's progression.