Hemophagocytic lymphohistiocytosis following dengue hemorrhagic fever in Hb H/Hb Constant Spring patient.

Infection-associated hemophagocytic syndrome (IAHS), a secondary form of hemophagocytic lymphohistiocytosis (HLH), has been found following several types of infections and can be fatal. We report herein a case of IAHS following dengue infection in a 14-year-old patient with underlying α-thalassemia syndrome (non-deletional Hb H/Hb Constant Spring disease). He developed prolonged fever, thrombocytopenia, and progressive splenomegaly. Further investigations indicated hyperferritinemia, and increased reactive histiocytes with hemophagocytic activity in the bone marrow. He responded promptly to dexamethasone and i.v. immune globulin. Physicians should be aware of this condition, especially in countries where both dengue hemorrhagic fever and thalassemia are prevalent. The fatal outcome of IAHS can be prevented with prompt appropriate treatment.