A Case of Adult-Onset Still's Disease Presenting with Urticated Plaques and Acute Myopericarditis.

Adult onset Still's disease (AOSD) is a systemic inflammatory disorder of unknown etiology characterized by spiking fever, evanescent skin rash, arthralgia or arthritis, involvement of various organs, and predominantly neutrophilic leucocytosis. AOSD, although uncommon, has a characteristic constellation of clinical and laboratory features and should be considered in the differential diagnosis of pyrexia of unknown origin associated with a rash and arthralgia. The diagnosis is one of clinical suspicion and it is essential that infections, malignancy, and other rheumatic diseases are excluded. We report a case which illustrates the typical features of AOSD that were treated with steroids and azathioprine.