Classification criteria for psoriasis and psoriatic arthritis

Abstract

Classifi cation criteria are primarily for assembling meaningfully homogenous groups of patients for the purpose of clinical research. They are not for diagnosis in clinical interactions between physicians and patients. The classifi cation criteria most commonly used for psoriatic arthritis currently are the CASPAR criteria, which demonstrate high levels of accuracy in a variety of contexts. Classifi cation criteria do not resolve challenges to disease concept but simply refl ect current understanding and may evolve with greater knowledge of the pathophysiological basis of psoriatic arthritis. Recent classifi cation criteria for spondyloarthritis, among which psoriatic arthritis is included, has identifi ed additional challenges for disease concept.