An uncommon presentation of EBV-driven HLH. Primary or secondary? An ongoing dilemma.

Haemophagocytic lymphohistiocytosis (HLH) is a potentially fatal syndrome, mainly characterised by dysregulated immune activation. The syndrome is related to a genetic cause, in the classic primary form, or to identified triggers such as infections, malignancy or rheumatological processes, in the classic secondary form. Epstein-Barr virus (EBV) is the most common agent implicated in hereditary and non-hereditary conditions. We describe a 23-month-old girl who experienced severe clinical deterioration with respiratory distress due a bilateral pleural effusion within the first week of primary EBV infection. Fever, generalised oedema and hepatosplenomegaly, along with a pruritic morbilliform erythematous rash, were the first clinical signs. Respiratory impairment followed with hypoxaemia and the patient was admitted to the intensive care unit for thoracocentesis. Further investigation showed persistent bicytopaenia, hypertriglyceridaemia, hyperferritinaemia and elevated α chain of interleukin-2 receptor (sCD25). Diagnostic criteria for HLH were fulfilled. Therapy was instituted with dexamethasone, ciclosporin A and intravenous immunoglobulin 6 days after admission with progressive clinical recovery.