Palindromic rheumatism as part of the rheumatoid arthritis continuum.

Palindromic rheumatism is a distinctive syndrome that has a long-recognized association with rheumatoid arthritis (RA). Palindromic rheumatism is characterized by intermittent flares of pain, erythema and swelling in and around the joints, which are typically severe and unpredictable. The observation that most patients with palindromic rheumatism have RA-related autoantibodies and that many eventually develop RA has led to palindromic rheumatism often being viewed as a relapsing-remitting variant of RA. However, the clinical and imaging phenotypes of palindromic rheumatism suggest important distinctions from RA and imply underlying mechanistic differences between the two conditions. Furthermore, the pattern of inflammation seen in palindromic rheumatism has interesting parallels with that seen in other groups of symptomatic individuals at risk of developing RA. In this Review, we explore the concept of palindromic rheumatism as part of the RA continuum and propose an updated disease paradigm for this unique syndrome.