Visceral Leishmaniasis Presenting as Hemophagocytic Lymphohistiocytosis in a Non-endemic Setting: A Case Report

Visceral leishmaniasis (VL) is a protozoal infection that can mimic other systemic inflammatory conditions, particularly in non-endemic regions.Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome that may occur secondary to infections, including leishmaniasis.We present the case of a 26-year-old immunocompetent man in the United Kingdom with fever, cytopenias, and hepatosplenomegaly.Despite broad-spectrum antimicrobial therapy, he remained persistently unwell with worsening laboratory parameters.Clinical features and laboratory findings raised suspicion of HLH, prompting treatment with anakinra; corticosteroids were added after diagnostic sampling.Further investigations confirmed VL through serology, polymerase chain reaction, and histopathology.The patient was treated with liposomal amphotericin B, resulting in rapid clinical improvement.This case illustrates the diagnostic challenge of identifying VL as the underlying trigger of HLH and the value of combining serological, molecular, and histopathological investigations when initial diagnostic findings are inconclusive in patients presenting with HLH features in non-endemic settings.