On defining musculoskeletal inflammation: a report from the GRAPPA 2011 annual meeting.

At the 2011 annual meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA), members discussed the need to develop a framework for defining inflammatory arthritis, enthesitis, dactylitis, and spondylitis, particularly as they relate to psoriatic arthritis (PsA). GRAPPA members first addressed this subject at their 2010 meeting, where the CASPAR (ClASsification of Psoriatic ARthritis) criteria were discussed. Although these are classification criteria, the CASPAR are also often applied as a diagnostic measure by clinicians screening for PsA, particularly its core criterion: recognizing the presence of inflammatory musculoskeletal disease. In breakout group discussions, GRAPPA members discussed the difficulties in recognizing overlapping or mimicking features that may result in underdiagnosing or misdiagnosing PsA.