A Rare, Potentially Fatal Complication of a Common Virus: Epstein-Barr Virus-Induced Hemophagocytic Lymphohistiocytosis in Adolescence.

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening hyperinflammatory syndrome that requires rapid recognition and treatment. We describe a 19-year-old female patient with a history of Graves' disease who presented with Epstein-Barr virus (EBV) infection, severe pancytopenia, and was subsequently diagnosed with EBV-induced HLH. The presence of Graves' disease, an autoimmune thyroid disorder, likely contributed to underlying immune dysregulation, predisposing the patient to an exaggerated immune response when exposed to EBV. This case highlights the importance of maintaining a high index of suspicion for HLH in patients with autoimmune conditions complicated by infection. Equally important is identifying the underlying trigger, as treatment strategies may differ, and include targeted therapies such as monoclonal antibodies in addition to, or in place of, traditional bone marrow-suppressive regimens.