Haemophagocytic lymphohistiocytosis secondary to Epstein-Barr and cytomegalovirus coinfection

Haemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening disorder caused by uncontrolled activation of the immune system, leading to phagocytosis of blood cells and cytokine storm. HLH can manifest in childhood due to a genetic mutation, but in adults HLH arises secondary to viral infections, autoimmune diseases or neoplastic processes. The most common viral infections associated with HLH are Epstein-Barr virus (EBV) and cytomegalovirus (CMV). EBV and CMV coinfection associated with HLH, however, is exceedingly rare. We present a case of HLH secondary to EBV and CMV coinfection in a young adult who presented with recurrent intermittent high-grade fevers and epistaxis. This case illustrates the importance of considering HLH in patients with idiopathic fevers and to consider all the potential aetiologies for HLH to ensure proper treatment.