Persistent fever of unknown origin in two young infants caused by the atypical form of Kawasaki disease

Two previously healthy infants, a boy and a girl aged 3 and 4 months, respectively, were admitted for fever of unknown origin with laboratory results indicating an inflammation. The boy presented with vomiting, pyuria, anaemia, and thrombocytosis. The girl presented with irritability, erythema and diarrhoea. All viral and bacterial cultures remained negative and supplementary radiology was unable to detect a focus of infection. The fever had persisted for at least 12 days in both cases before the diagnosis 'atypical Kawasaki diseases was considered. Cardiac echograms showed dilatation of the coronary arteries in both patients and confirmed the diagnosis. Immediate therapy with intravenous immunoglobulins and acetylsalicylic acid was given, whereupon the fever subsided within 24 hours; the further clinical course was uneventful. These cases illustrate the fact that atypical Kawasaki disease is often a late consideration, especially when the symptoms of the classical form are absent. This condition should be considered in every infant presenting with long-lasting unexplained fever.