Psoriatic Arthritis Diagnosis

During a physical examination, the doctor will identify skin lesions, tenderness, and swelling of joints. Joint x-rays may be performed.

Basic diagnosis information for Psoriatic Arthritis

Skin and nail changes characteristic of psoriasis with accompanying arthritic symptoms are the hallmarks of psoriatic arthritis. A blood test for rheumatoid factor, antibodies that suggest the presence of rheumatoid arthritis, is negative in nearly all patients with psoriatic arthritis. X rays may show characteristic damage to the larger joints on either side of the body as well as fusion of the joints at the ends of the fingers and toes.

Test used in a Psoriatic Arthritis Diagnosis

X-rays to look for changes in your bones and joints

Blood tests to rule out other diseases, such as rheumatoid arthritis and document the presence of inflammation

Joint fluid tests to rule out gout, another arthritis-related disease that may resemble psoriatic arthritis. The joint fluid in most people with psoriatic contains many inflammatory cells and although the absence of uric acid crystals may rule out gout, many other inflammatory forms of arthritis will have a similar number of white cells in the fluid. The knee is the easiest joint from which to obtain joint fluid for analysis and can only be removed by putting a needle in the joint (the procedure is called arthrocentesis) if the joint is swollen.

It may take some time to determine if you have psoriatic arthritis. Usually, if your nails and skin are affected along with your joints, a concrete diagnosis can be made. In general, a rheumatologist (a physician trained in the diagnosis and treatment of arthritis) can recognize the features of psoriatic arthritis noted above in the setting of psoriasis and make a diagnosis. A firm diagnosis will have to wait the development of the skin disease. The skin disease or the arthritis may appear first.