Psoriasis is a skin inflammation that occurs in about 1% of the population. 20% of people with PsO get PsA.
CASPAR critieria [1]
| Confirmed inflammatory articular disease (joint, spine, or entheseal) | |
| with at least 3 points from the following features: | |
| current psoriasis (assigned a score of 2 points; all other features are assigned a score of 1) | 2 |
| a history of psoriasis or a family history of psoriasis (unless current psoriasis is present) | 1 |
| dactylitis | 1 |
| juxtaarticular new bone formation (hands or feet) | 1 |
| rheumatoid factor (RF) negativity (except latex test) | 1 |
| psoriatic nail dystrophy | 1 |
[1] The ClASsification for Psoriatic ARthritis (CASPAR) Criteria – A Retrospective Feasibility, Sensitivity, and Specificity Study. WILLIAM TILLETT, LUISA COSTA, DEEPAK JADON, DINNY WALLIS, CHARLOTTE CAVILL, JESSICA McHUGH, ELEANOR KORENDOWYCH and NEIL McHUGH. The Journal of Rheumatology January 2012, 39 (1) 154-156; DOI: https://doi.org/10.3899/jrheum.110845