Question: What Are the Differences Between Psoriatic Arthritis and Rheumatoid Arthritis?
There are over 100 types of arthritis. What are the differences in the clinical picture of psoriatic arthritis and rheumatoid arthritis, other than the obvious additional symptoms of the skin disease psoriasis?
Answer: Joint inflammation and stiffness in patients with psoriasis and rheumatoid arthritis share a common feature. Both conditions are caused by an erosive inflammatory arthritis. The distribution of joint involvement however, differs between the two diseases.
Classic rheumatoid arthritis is a symmetrical disease primarily involving the PIP joints and wrists. Rheumatoid arthritis nodules are often present. Psoriasis is an asymmetric disease most often causing "sausage deformities" of the digits, and deformities of the DIP joints of fingers and toes involved with psoriatic nail changes. Typically, skin lesions are associated with psoriasis. Sometimes proliferative synovitis of the wrists and fingers occur, resembling rheumatoid arthritis. In these cases, x-rays and laboratory testing help to differentiate the two diseases. Treatment for both conditions are similar, using anti-inflammatory agents, anti-malarials, and adding methotrexate for stubborn cases.
Answer provided by the late Dr. Raymond Federman, a respected rheumatologist.