Psoriatic arthritis is a type of arthritic inflammation that occurs in about 15 percent of patients who have a skin rash called psoriasis. This particular arthritis can affect any joint within the body, with symptoms that vary from person to person. Research has shown that persistent inflammation from psoriatic arthritis can lead to joint damage. Fortunately, available treatments are effective for most people.
Psoriasis is a disease in which scaly red and white patches develop on the skin. Those with psoriasis can also develop psoriatic arthritis when the body's immune system goes into overdrive to attack the skin disease, causing inflammation. Like psoriasis, psoriatic arthritis symptoms flare and subside, varying from person to person, and even changing locations in the same person over time.
Psoriatic arthritis can affect any joint within the body, either in a single joint or in the same joint on both sides of the body, e.g., one or both knees. Affected fingers and toes can resemble swollen sausages, a condition often referred to as dactylitis.
Psoriatic arthritis in the spine, called spondylitis, causes pain in the back or neck, and difficulty bending. It can also cause tender spots at sites in the body where tendons and ligaments join onto bones. This condition, called enthesopathy, can result in pain at the back of the heel, the sole of the foot, or other areas.
Recent research suggests that persistent inflammation from psoriatic arthritis causes joint damage later so diagnosis is essential. Fortunately, treatments are available and effective for most people.
What causes psoriatic arthritis is not known exactly. Of those with psoriatic arthritis, 40 percent have a family member with psoriasis or arthritis, suggesting heredity may play a role. Psoriatic arthritis can also result from an infection that activates the immune system. While psoriasis itself is not infectious, it might be triggered by a streptococcal throat infection.
Psoriatic arthritis usually appears in people between the ages of 30 to 50, but can begin as early as childhood. Men and women are equally at risk. Approximately 15 percent of people with psoriasis develop psoriatic arthritis. At times, the arthritis can appear before the skin disorder.