Photochemotherapy and psoriatic arthritis. A prospective study.

We have studied the temporal relation between psoriasis and psoriatic arthritis in 27 patients receiving photochemotherapy for treatment of psoriasis. Patients were classified as either spondylitic or nonspondylitic. For spondylitic patients, psoriasis was difficult to control, arthritis did not improve, and skin and joint activity appeared to vary independently. In contrast, 67% of nonspondylitic patients receiving photochemotherapy treatment remained clear of psoriasis, with 49% mean improvement in articular index. There was an inverse relation between initial percentage of psoriasis and improvement in peripheral arthritis. These results suggest that aggressive management of psoriasis helps control synovitis in at least a subgroup of patients with psoriatic arthritis.