RESUMO
Hemophagocytic lymphohistiocytosis (HLH) associated with herpes simplex virus (HSV)-1 infection (HSV-1-HLH) is uncommon and is potentially fatal without appropriate treatment. We herein report the case of an adult patient with HSV-1-HLH who was successfully treated with acyclovir. A 69-year-old man developed fever, pancytopenia and liver enzyme elevation after the resolution of pneumonia. These findings and the presence of hemophagocytosis in the patient's bone marrow were consistent with a diagnosis of HLH. The patient was diagnosed with HSV-1-HLH based on the results of a polymerase chain reaction (PCR) for HSV-1. The early administration of acyclovir improved his clinical symptoms and laboratory results within two weeks. In the present case, the rapid and precise diagnosis facilitated the successful treatment of HSV-1-HLH.