Hemophagocytic lymphohistiocytosis and Kawasaki disease: combined manifestation and differential diagnosis.

Both hemophagocytic lymphohistiocytosis (HLH) and Kawasaki disease (KD) are diagnosed in patients with prolonged resistant fever by using a scoring system. Concurrent manifestation of both conditions has been reported previously. We describe an infant of 7 weeks whose condition fulfilled the criteria of HLH, but who, after clinical response to treatment, suddenly died from a myocardial infarction at 11 weeks. Post-mortem examination revealed a previously unknown coronary arteritis typical for KD. Since it is difficult to distinguish between KD and HLH, both diseases should be considered in young children with overlapping symptoms. Repeated echocardiograms may be helpful in these cases. (c) 2009 Wiley-Liss, Inc.