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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Cite this: Herbert S. Diamond, Eric M. Ruderman, Marina Magrey. Fast Five Quiz: Psoriatic Arthritis Presentation and Diagnosis - Medscape - Jan 25, 2023.