What is psoriatic arthritis?
Psoriatic arthritis (PsA) is a form of chronic inflammatory arthritis that is associated with the skin condition psoriasis. Between 10-30% of people with psoriasis will develop psoriatic arthritis and it affects both men and women equally. It typically shows up about 10 years after the onset of psoriasis. While most people with psoriasis are diagnosed between the ages of 15 and 35, it can be diagnosed at any age.
Psoriatic arthritis has a range of symptoms and can show up differently in different individuals. However, some of the common symptoms include:
- painful, swollen joints
- tenderness where muscles or ligaments attach to bones, particularly the heel and bottom of the foot
- back pain
- nail changes such as separating from the nail bed, or becoming pitted or infected-looking
- morning stiffness
- general fatigue
- reduced range of motion
- redness and pain in tissues surrounding the eyes (conjunctivitis)
There are five general patterns of of psoriatic arthritis, each with similar but distinctive symptoms:
Symmetric arthritis appears much like rheumatoid arthritis. The symptoms are similar to RA, joint swelling, pain and stiffness, but generally milder with less deformity. It usually occurs in the same joints on both sides of the body (hence the term symmetric) and can be disabling.
Asymmetric arthritis is one of the mildest forms PsA, affecting affects one to three joints on different sides of the body. It can affect any joint, such as the knee, hip, ankle or wrist. Some people may develop a painful, sausage-like swelling of the fingers and/or toes called dactylitis. The joints may be warm, tender and red, and pain may come and go, but usually responds to medical therapy.
Distal interphalangeal predominant (DIP or distal pattern) occurs in only about 5 percent of people who have the disease. It involves the end joints of the fingers closest to the nails. Nail changes, such as pitting, discoloration, white areas, crumbling or detachment are usually prominent and help to distinguish it from osteoarthritis.
Spinal pattern or Spondylitis affects the spinal column. It is found in about 5% of people with PsA. Inflammation with stiffness of the neck, lower back, sacroiliac or spinal vertebrae are common symptoms, making motion painful and difficult. Some people also experience symptoms in the hands, arms, hips, legs and feet.
Destructive pattern or Arthritis mutilans is a severe, deforming and destructive condition that affects fewer than 5% of people with psoriatic arthritis. It usually affects the small joints.