 The incidence of PR is less than that of RA but is not as rare as that was thought to be.Palindromic rheumatism is a syndrome presented with inflammatory para-arthritis (soft tissue rheumatism) and inflammatory arthritis both of which cause sudden inflammation in one or several joints or soft tissue around joints.The flares usually present with mono- or oligo-articular involvement, which have onset over hours and last a few hours to a few days, and then go away completely.