Classification criteria: peripheral spondyloarthropathy and psoriatic arthritis.

Recent proposals for re-classification of spondyloarthropathies according to the predominance of peripheral and axial manifestations and for non-radiographic ankylosing spondylitis to be re-named axial spondyloarthritis are reviewed. It is argued that such proposals are less likely to advance knowledge in the study of spondyloarthopathies and that accurate classification criteria for defined diseases, for example psoriatic arthritis, remain as necessary now as they ever did. The CASPAR criteria remain the best performing classification criteria for psoriatic arthritis.