ARTHRITIS INVOLVING THE JOINTS AND SKIN
Psoriatic arthritis is an inflammatory condition that is related to the skin condition psoriasis. It is often accompanied by tell-tale skin patches of raised red areas that have a crusty, silvery scale. The skin lesions usually appear on the scalp, elbows, knees or lower back, but they may appear anywhere on the body.
About 10 percent of Americans with psoriasis also have the arthritic form of the disease. Abnormalities of the fingernails and toenails in patients with psoriasis increase the likelihood that they will develop the arthritic form of the disease. Psoriatic arthritis strikes men and women equally, and is usually diagnosed between the ages of 30 and 50. Among people who have first-degree relatives (parents and siblings) with psoriatic arthritis, there is an increased risk of developing the disease.
Psoriatic arthritis is a seronegative spondyloarthropathy. It is diagnosed through physical examination, x-rays and laboratory tests. Lab test abnormalities seen with psoriatic arthritis often mimic RA, except the rheumatoid factor is usually absent and HLA-B27 is present. Psoriatic changes in the skin and nails must also be present before a definitive diagnosis of psoriatic arthritis is made. Treatment focuses on medications to relieve the inflammation, including NSAIDs, Azulfidine® (sulfasalazine), methotrexate and TNF blockers.
Five Patterns of Psoriatic Arthritis
There are five types of psoriatic arthritis. Each is distinguished by the pattern of the involved joints, but all are associated with skin psoriasis.
Symmetric psoriatic arthritis. Symmetric psoriatic arthritis is the most common form of psoriatic arthritis. It involves pain and swelling in many joints, particularly the small joints of the fingers and toes. It is similar to rheumatoid arthritis in that it affects the same joints on opposite sides of the body.
Asymmetric psoriatic arthritis. Asymmetric psoriatic arthritis involves a few joints of the extremities, but in a random pattern, such as the fingers on the left hand and toes on the right foot.
Psoriatic spondylitis. Psoriatic spondylitis affects specific joints of the lower spine called the sacroiliac joints.
Distal interphalangeal predominant psoriatic arthritis. This form of psoriatic arthritis primarily involves the joints closest to the nails of the fingers and toes. It may also affect other joints. This form of the disease often involves changes in the nails, including pitting, splitting or degeneration.
Arthritis mutilans. The fifth type of psoriatic arthritis is arthritis mutilans. It is a very rare, painful and destructive form of psoriatic arthritis that involves inflammation where tendons and ligaments attach to the bone (a condition called enthesitis).
Scott Zashin, MD, PA is a respected Texas psoriatic arthritis Doctor/Specialist with an office in Dallas. The above information about psoriatic arthritis is from his arthritis book: Arthritis Without Pain, a comprehensive guide for patients considering or undergoing treatment with the TNF blockers Enbrel®, Remicade®, or Humira®. All rights reserved.