 It is thought to be an autoimmune disease, possibly an abortive form of rheumatoid arthritis.The exact prevalence of palindromic rheumatism in general population is unknown, and this condition is often considered a rare disease by nonrheumatologists.However, recent Canadian study showed that the incidence of PR in a cohort of incident arthritis was one case of PR for every 1.8 cases of rheumatoid arthritis (RA).