['Hemophagocytic lymphohistiocytosis (HLH) is a syndrome composed of macrophage activation syndrome (MAS), infection-associated hemophagocytosis syndrome (IAHS), malignancy-associated HLH and genetic HLH. Differentiation of MAS from IAHS and other HLH is important for early appropriate treatment.', 'A retrospective analysis was used to differentiate childhood MAS from IAHS and other HLH in Chang Gung Memorial Hospital (CGMH), Kaohsiung. All relevant clinical features, laboratory data, treatments and outcomes were analysed.', 'Seventeen patients with childhood HLH were found at CGMH, Kaohsiung in the past decade, and could be classified into 3 categories: IAHS (9 patients), MAS (5 patients), and HLH of unknown etiology (3 patients). The diagnosis of MAS first appeared in this hospital in 2001. Patients with IAHS tended to be younger than those with MAS. Boys were more frequently found in the IAHS group whereas girls (with systemic lupus erythematosus or juvenile idiopathic arthritis) were more frequently found in the MAS group. The majority of mortality cases were noted in the IAHS group (44%, 4/9). All patients with MAS survived with early cyclosporine A treatment.'] Does childhood macrophage activation syndrome differ from infection-associated hemophagocytosis syndrome in etiology and outcome in Taiwan?