What is psoriatic arthritis?
Psoriatic arthritis is a type of arthritis linked with psoriasis, a chronic skin and
nail disease. Psoriasis causes red, scaly rashes and thick, pitted fingernails.
Psoriatic arthritis is similar to rheumatoid arthritis (RA) in symptoms and joint
swelling (inflammation). But it tends to affect fewer joints than RA. And it does not
make the typical RA antibodies. The arthritis of psoriatic arthritis comes in 5
- Arthritis that affects the small joints in the fingers, toes, or both
- Asymmetrical arthritis of the joints in the hands and feet
- Symmetrical polyarthritis, which is similar to RA
- Arthritis mutilans, a rare type of arthritis that destroys and deforms joints
- Psoriatic spondylitis, arthritis of the lower back (sacroiliac sac) and the
What causes psoriatic arthritis?
Doctors don’t know what causes psoriatic arthritis. But factors such as immunity,
genes, and the environment may play a role.
What are the symptoms of psoriatic arthritis?
psoriasis symptoms may start before or after the arthritis. Psoriasis causes red, scaly
rashes and thick, pitted fingernails. About 3 in 20 to 3 in 10 people with psoriasis
may develop psoriatic arthritis. Symptoms of psoriatic arthritis may include:
- Inflamed, swollen, and painful joints, often in the fingers and toes
- Deformed joints from chronic inflammation
The symptoms of psoriatic arthritis can look like other health conditions. Make sure to see your healthcare provider for a diagnosis.
How is psoriatic arthritis diagnosed?
Psoriatic arthritis is easier to confirm if you already have psoriasis. If you don’t
have the skin symptoms, diagnosis is more difficult. The process starts with a health
history and a physical exam. Your healthcare provider will ask about your symptoms. You
may have blood tests to check the following:
- Erythrocyte sedimentation rate (ESR or sed rate). This test looks at how quickly red blood cells fall to the bottom of a test tube. When swelling and inflammation are present, the blood’s proteins clump together and become heavier than normal. They fall and settle faster at the bottom of the test tube. The faster the blood cells fall, the more severe the inflammation.
acid. High blood uric acid levels can be seen in psoriatic arthritis but are
not used for diagnosis or monitoring.
Imaging. X-rays, CT scans, ultrasound, MRI, and
skin biopsies may all be used to help diagnosis.