Table 14.20-5. CASPAR criteria for classification of psoriatic arthritis

To meet the CASPAR criteria, the patient must have inflammatory articular disease (joint, spine, or enthesitis) plus ≥3 points from any of the following 5 categories:

1. Evidence of psoriasis:

1) Evidence of current psoriasis (psoriatic lesions diagnosed by a rheumatologist or dermatologist): 2 points

2) Personal history of psoriasis or family history of psoriasis (in a first-degree or second-degree relative): 1 point

2. Typical psoriatic nail dystrophy (onycholysis, pitting, and hyperkeratosis) observed on current physical examination: 1 point

3. Negative test result for rheumatoid factor (any assay except for the latex test), preferably using ELISA or nephelometry: 1 point

4. Current dactylitis (defined as swelling of an entire digit [so-called sausage digit]) or history of dactylitis recorded by a rheumatologist: 1 point

5. Radiographic evidence of juxta-articular new bone formation seen as ill-defined ossification near joint margins (excluding osteophyte formation) in the hand or foot: 1 point

Adapted from Arthritis Rheum. 2006;54(8):2665-73.

CASPAR, ClASsification criteria for Psoriatic ARthritis; ELISA, enzyme-linked immunosorbent assay.