The CASPAR criteria for classifying psoriatic arthritis
| Inflammatory articular disease (joint, spine or entheseal), with three or more points from the following: | ||
|---|---|---|
| 1. Evidence of psoriasis | (a) Current psoriasis* or | Psoriatic skin or scalp disease present today as judged by a rheumatologist or dermatologist |
| (b) Personal history of psoriasis or | A history of psoriasis that may be obtained from patient, family doctor, dermatologist, rheumatologist or other qualified healthcare provider | |
| (c) Family history of psoriasis | A history of psoriasis in a first- or second-degree relative according to patient report | |
| 2. Psoriatic nail dystrophy |
| Typical psoriatic nail dystrophy including onycholysis, pitting and hyperkeratosis observed on current physical examination |
| 3. A negative test for rheumatoid factor |
| By any method except latex but preferably by ELISA or nephelometry, according to the local laboratory reference range |
| 4. Dactylitis | (a) Current or | Swelling of an entire digit |
| (b) History | A history of dactylitis recorded by a rheumatologist | |
| 5. Radiological evidence of juxta-articular new bone formation | Ill-defined ossification near joint margins (but excluding osteophyte formation) on plain radiographs of hand or foot | |
*Current psoriasis scores 2 points. CASPAR = Classification Criteria for Psoriatic Arthritis; ELISA = enzyme-linked immunosorbent assay