Psoriatic arthritis is a chronic inflammation of the joints that occurs in some people with a chronic skin and nail condition known as psoriasis. Psoriasis causes flare-ups of raised patches of skin covered with silvery scales. The onset of psoriasis may occur at any age but is most commonly seen between the ages of 15 and 50 years. Psoriatic arthritis can be noted before or after the skin lesions appear.

What is going on in the body?

What are the causes and risks of the disease?
Psoriatic arthritis occurs only in people with underlying psoriasis. Psoriasis occurs more often in people of European ancestry. Approximately 5% to 8% of people with psoriasis will develop this form of arthritis. It affects men and women equally.

While the exact cause of psoriatic arthritis is unknown, several factors are suspected to be triggers for the disease. These factors include the following:
- environment
- the person's immune system
- genetics

Both psoriasis and psoriatic arthritis flare up in people with HIV, the immunodeficiency disorder associated with AIDS.

What are the treatments for the disease?
Much of the joint damage may appear in the beginning stages of the disease. For this reason, early treatment of psoriatic arthritis may be critical.

Following are medications used to treat psoriatic arthritis:
- immunosuppressant medications, which alter the body's immune response. Methotrexate, a medication also used as cancer chemotherapy, is commonly used to treat psoriatic arthritis. Other immunosuppressant medications include azathioprine and cyclophosphamide.
- anti-inflammatory medications, such as aspirin, naproxen, or ibuprofen
- COX-2 specific inhibitor NSAIDs, such as celecoxib and rofecoxib
- corticosteroids, such as prednisone, which are taken orally or by injection into the joint
- antibiotics, such as doxycycline and minocycline
- disease-modifiying medications, such as sulfasalazine and hydroxychloroquine. These medications help to slow down the joint destruction associated with the disease.

Other treatments for psoriatic arthritis may include:
- education about the course of the disease and methods to preserve joint function
- physical therapy to help maintain joint strength and range of motion
- occupational therapy to learn energy conservation techniques
- reduction of stress
- splints to rest acutely inflamed joints
- assistive devices, such as zipper pulls, to decrease strain on joints
- healthy diet following the food guide pyramid, with adequate calories, protein, and calcium

Exercise is important in the treatment of arthritis. Thirty minutes of moderate exercise a day can help to prevent complications of arthritis, as well as heart disease, stroke, and diabetes. A person exercising at a moderate level can talk normally without shortness of breath and is comfortable with the pace of the activity. The 30 minutes a day can be done in one session, or it can be broken up into smaller segments. Low impact aerobics and water aerobics are examples of exercises that minimize joint stress.

Surgery may be performed when pain cannot be controlled or function is lost. Common procedures include the following:
- arthroscopy, a procedure that uses a small scope and instruments to get inside the joint without opening it
- arthrotomy, which involves opening the joint through a larger incision
- synovectomy, which is the removal of the lining of the joint
- osteotomy, which refers to the realignment of the bone next to the joint
- arthroplasty, which is the partial or total replacement of the joint. Individuals with severe arthritis are often candidates for a knee joint replacement or a hip joint replacement.

There has been a great deal of interest lately in the use of glucosamine and chondroitin, dietary supplements that may decrease joint pain associated with arthritis. A large scale study is currently being conducted by the National Center for Complementary and Alternative Medicine and the National Institute of Arthritis and Musculoskeletal Disease to determine the effectiveness of these supplements.

What are the side effects of the treatments?

What happens after treatment for the disease?
Treatment of rheumatoid arthritis is lifelong. There is no cure for the disease, but careful management can help to minimize some of its effects. Periodic flare-ups of the disease are common.

How is the disease monitored?
A healthcare provider will monitor the person's level of comfort and function of the joint. Any new or worsening symptoms should be reported to the healthcare provider.