Table 1.

CASPAR criteria⁷⁵ for the diagnosis of PsA.

Criterion	Description
1. Evidence of psoriasis
Current psoriasis	Psoriatic skin or scalp disease as judged by rheumatologist or dermatologist
Personal history of psoriasis	History of psoriasis that may be obtained from patient, family physician, dermatologist, rheumatologist
Family history of psoriasis	History of psoriasis in first- or second-degree relative according to patient
2. Psoriatic nail dystrophy	Onycholysis, pitting, and hyperkeratosis
3. Negative test for rheumatoid factor	Determined by any method, except latex, but preferably by enzyme-linked immunosorbent assay or nephelometry; based on reference range of local laboratory
4. Dactylitis
Current dactylitis	Swelling of entire digit
History of dactylitis	History as recorded by rheumatologist
5. Radiographic evidence of juxtaarticular new bone formation	Ill-defined ossification near joint margins (excluding osteophyte formation) on radiographs of hands or feet

A patient must have inflammatory articular disease (joint, spine, or entheseal) with a score of  ≥ 3 points of the following 5 criteria. Current psoriasis is assigned a score of 2, while all other features are assigned a score of 1.