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Psoriatic Arthritis Health Center

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Psoriatic Arthritis Tests and Diagnosis

An accurate and early diagnosis of psoriatic arthritis will help you avoid the damage and deformity it can cause.

Your doctor will make a decision based on:

  • Your symptoms
  • A physical exam
  • Your medical history and your family's
  • Lab tests

No single thing will diagnose psoriatic arthritis, but blood tests, imaging, and other tests can help your doctor. He may want to give you certain tests that check for rheumatoid arthritis, because it can look a lot like psoriatic arthritis.

Along with your symptoms, the most telling signs are the skin and nail changes you get with psoriasis, or specific changes in your X-rays.

Symptoms and Family History

Psoriatic arthritis usually shows up between ages 30 and 50, but it may start in childhood. Both men and women get it. Many people have the skin disease psoriasis first.

Your doctor will look at your body and ask about the symptoms you've been having, which might include:

  • Joint pain, stiffness, and swelling
  • Fatigue
  • Tenderness, pain, or swelling where tendons and ligaments attach to bones
  • Swollen fingers or toes
  • Patches of red, itchy skin
  • Thick silver or gray scaly areas on your skin
  • Changes or problems with your fingernails or toenails
  • Redness and swelling in your eye

Both psoriasis and psoriatic arthritis are related to your genes, so if you have a close family member with these skin or joint problems, you're more likely to have them, too.

Blood Tests

Erythrocyte sedimentation rate (sed rate or ESR) gives a rough idea of how much inflammation is in your body, which could be caused by psoriatic arthritis. But higher levels can come from other autoimmune diseases, an infection, a tumor, liver disease, or pregnancy, too.

Rheumatoid factor (RF) and anti-CCP antibody tests can rule out rheumatoid arthritis. People with that condition may have higher levels of these in their blood.

More than half of people who have psoriatic arthritis with spine inflammation will have the genetic marker HLA-B27. You can get tested to find out if you do.

People with psoriatic arthritis may have mild anemia, or not enough healthy red blood cells.


These can show cartilage changes or bone injury that suggest arthritis in your spine and joints in your lower back and hands. Psoriatic arthritis usually looks different on X-rays than rheumatoid arthritis does.

Bone Density

Because psoriatic arthritis may lead to bone loss, your doctor may want to measure your bone strength. You could be at risk for osteoporosis and fractures.

WebMD Medical Reference

Reviewed by David Zelman, MD on May 20, 2015
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