Sacroiliitis in severe psoriasis.

In 100 consecutive patients admitted to the hospital for control of severe psoriasis, 25 had radiologic changes characteristic of psoriatic arthritis. Twenty had erosions and mild sclerosis around the sacroiliac joint; in eight of these, asymptomatic sacroiliac changes were the sole manifestation of musculoskeletal disease. Twelve had vertebral syndesmophytes, 11 had terminal interphalangeal joint changes, and 10 had peripheral joint involvement.