Psoriatic arthritis is a condition that stems from psoriasis, an autoimmune disease in which the body’s immune system attacks the skin, resulting in scaly, red patches on the skin. In some psoriasis patients, the immune system attacks the joints as well, leading to inflammation and the condition known as psoriatic arthritis. Overall about 1 to 3 % of the population of the United States has psoriasis and approximately 30% of people with psoriasis have psoriatic arthritis.
Psoriatic arthritis typically affects people between the ages of 30 and 50 and individuals and although the majority of affected individuals will have psoriasis of the skin, although some will develop joint disease prior to skin manifestations. Symptoms of psoriatic arthritis are highly variable among patients, coming and going over time and affecting one or many joints of the body. Psoriatic arthritis can be painful and could affect any joint in the body, especially larger ones in the lower extremities, the joints of fingers and toes, and the spine. But it can also cause swelling in areas where tendons and ligaments attach to bones, known as enthesitis, or swelling of an entire finger or toe, known as dactylitis.
In recent years a variety of biologic medications have become available that have improved the treatment of psoriatic arthritis.
Silman AJ, Hochberg MC. Epidemiology of the rheumatic diseases. 2nd edition: Oxford University Press; 2001.
Helmick CG, Felson DT, Lawrence RC et al. Estimates of the prevalence of arthritis and other rheumatic conditions in the United States. Part I. Arthritis & Rheumatism. 2008;58:15-25.
National Institutes of Health, National Institute of Arthritis and Musculoskeletal and Skin Disease. Handout on Health: Arthritis.