The most common background for recurrent pericarditis is that of acute nonspecific pericarditis. Relapsing pericarditis also may follow cardiac trauma, cardiac operations, myocardial infarction, and intrapericardial bleeding. The exact recurrence rate after initial attacks of idiopathic pericarditis is unknown but appears to be in the range of 15% to 32%. The mechanism of recurrent pericarditis is uncertain. An autoimmune response has been proposed, but this concept is unproved. Yoneda and coworkers, in a case of pericarditis due to coxsackie B virus, found no rise in antibody titer to this virus during recurrences. The prognosis, except for disabling pain and malaise, is good, and constrictive pericarditis, chronic myocardial disease, and cardiac tamponade are unusual complications. Although constrictive pericarditis may follow an initial attack of idiopathic pericarditis, it was reported in neither two other series of patients with relapsing pericarditis nor in this series. Cardiac tamponade has been reported as an occasional complication of relapses but did not occur in our patients. None of our patients died. Most patients with recurrent pericarditis respond to adrenal steroid therapy, but many times there is difficulty in weaning the patient from the drug. Because it is suspected that adrenal steroids may prolong attacks and promote tendency to further recurrences, initial therapy should be offered with aspirin or NSAIDs, and adrenal steroid therapy should be used only when there is no response to these agents. Recurrences may take place over a period lasting as long as 15 years, and patients with as many as 19 recurrences have been described.(ABSTRACT TRUNCATED AT 250 WORDS)