Psoriatic arthritis.

Psoriatic arthritis is a common form of arthritis. It is recognized that there is a subset of patients who have a severe, disabling form of the disease, and that patients need to be treated earlier if a good outcome is to occur. The pathogenesis of psoriatic arthritis is still unclear, but the "experiment of nature" provided by the HIV infection may help further outline the causative mechanisms. Newer modalities of therapy are being investigated.