Macrophage activation syndrome as the extreme form of Kawasaki disease

Few cases of macrophage activation syndrome (MAS) or reactive hemophagocytic lymphohistiocytosis (HLH) during the acute febrile phase of Kawasaki disease (KD) have been reported. We report on a case of a 19 month-old girl with MAS or reactive HLH during the course of KD. Despite immunoglobulin and steroid therapy, she showed persistent fever with hepatosplenomegaly and evidence of hemophagocytosis in the bone marrow. A high index of suspicion for clinical features associated with MAS is necessary for KD patients in order to provide appropriate treatment.