Fast Five Quiz: Psoriatic Arthritis Presentation and Diagnosis

Herbert S. Diamond, MD; Eric M. Ruderman, MD; Marina Magrey, MD


January 25, 2023

Plain radiography is the central imaging modality for assessing psoriatic arthritis; however, early in the disease course, there may be no radiographic findings. This is because soft-tissue swelling often precedes osseous findings.

No or only minimal juxta-articular osteoporosis is present in psoriatic arthritis. This can assist in the differential diagnosis, because juxta-articular osteoporosis is more prominent in rheumatoid arthritis.

Differentiating psoriatic arthritis from rheumatoid arthritis can be difficult. The following clinical pearls may aid in the diagnostic effort:

  • Psoriatic arthritis maintains bone mineralization and has periosteal reaction and new bone formation.

  • Psoriatic arthritis is usually RF-negative, whereas rheumatoid arthritis is RF-positive.

  • Psoriatic arthritis does not manifest with rheumatoid nodules.

  • Sausage digits and spontaneous joint fusion are common in psoriatic arthritis but not in rheumatoid arthritis.

Learn more about the use of imaging in the diagnosis of psoriatic arthritis.


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