PsA usually follows psoriasis - 60% to 70% of the time, but 15% to 20% of the time the PsA and the psoriasis appear within one year of each other. In only about 15% to 20% of cases does the arthritis present first.
When the arthritis presents first, it can create problems in diagnosis. Often patients are diagnosed with inflammatory polyarthritis or sero-negative RA.
There are no lab tests to diagnose PsA, but sometimes patient have a low positive RA titer or ANA. Often the CRP and Sed Rate are also elevated. If the patient has severe psoriasis, the uric acid levels may also be elevated.
On x-ray the damage caused by PsA looks different than the damage caused by RA, but the disease can still cause severe damage, so early treatment is important.
Treatment can resemble the treatment of RA. Methotrexate, Arava, and TNF inhibitors are used to treat the disease and prevent progression.
Early and aggressive treatment is important to prevent many of the deformities associated with PsA. If you believe you could have PsA, it is important to discuss this with your physician.
- Harrison's Rheumatology - 2nd Edition; Editor Anthony S. Fauci