Types of psoriatic arthritis

There are five types of psoriatic arthritis: symmetric, asymmetric, distal interphalangeal predominant (DIP), spondylitis and arthritis mutilans.

Symmetric arthritis is much like rheumatoid arthritis but generally milder with less deformity. It usually affects multiple symmetric pairs of joints (occurs in the same joints on both sides of the body) and can be disabling.

Asymmetric arthritis can involve a few or many joints and does not occur in the same joints on both sides of the body. It can affect any joint, such as the knee, hip, ankle or wrist. The hands and feet may have enlarged "sausage" digits. The joints may also be warm, tender and red. Individuals may experience periodic joint pain which is usually responsive to medical therapy. This form is generally mild, although some people might develop disabling disease.

Distal interphalangeal predominant (DIP) although the "classic" type, occurs in only about 5 percent of people with psoriatic arthritis. Primarily, it involves the distal joints of the fingers and toes (the joint closest to the nail). Sometimes it is confused with osteoarthritis, but nail changes are usually prominent.

Spondylitis is inflammation of the spinal column. In about 5 percent of individuals with psoriatic arthritis, spondylitis is the predominant symptom. Inflammation with stiffness of the neck, lower back, sacroiliac or spinal vertebrae are common symptoms in a larger number of patients, making motion painful and difficult. Peripheral disease can be present in the hands, arms, hips, legs and feet.

Arthritis mutilans is a severe, deforming and destructive arthritis that affects fewer than 5 percent of people with psoriatic arthritis. It principally affects the small joints of the hands and feet, though there is frequently associated neck or lower back pain.