This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Joint disorders, Subject name: Orthopaedics
CASPAR criteria is used in diagnosis of : 
Select and explain. 
A. Psoriatic ahritis, B. Rheumatoid ahritis, C. Ankyosing spondylitis, D. Reactive synovitis
A: Psoriatic ahritis
Answer: A: Psoriatic ahritis 
Explanation: CASPAR Criterion for Psoriatic Ahritis To be classified as having PsA, a patient must have inflammatory joint disease (joint, spine, enthesitis) with >= 3 of the following 5 criteria. 1. Evidence of psoriasis (One of these) a. Current psoriasis b. Personal history c. Family history 2. Psoriatic nail dystrophy 3. Negative RF 4. Dactylitis (One of a, b) a. Current b. History 5. Radiological evidence of Juxta-aicular new bone formation.