Psoriatic arthritis

In the past 10 years, a number of well-controlled surveys of psoriatic patients selective for the presence of arthritis have been conducted. A Canadian group reported that of 100 patients admitted to the hospital for treatment of psoriasis, 32 had clinical or radiologic evidence of psoriatic arthritis, and 17 had both types of evidence. Eighty patients with radiologic evidence of spinal or sacroiliac involvement were asymptomatic, and seven had clinical evidence of peripheral arthritis but without radiologic evidence. The authors concluded that psoriatic arthritis is a common event in patients with severe psoriasis and that it is associated with more extensive skin disease than is found in patients without arthritis. The information gathered from these epidemiologic studies coupled with clinical, radiologic, and serologic characteristics have provided the basis for the current belief that psoriatic arthritis is indeed a distinct entity