Hemophagocytic Lymphohistiocytosis in Leprosy: A Rare and Life-threatening Complication

Leprosy, a chronic mycobacterial disease, is caused by the acid-fast bacillus Mycobacterium leprae. The clinical manifestations of this disease depend on the host’s immunity against M. leprae. Hemophagocytic lymphohistiocytosis (HLH) is a rare complication that has been reported in association with leprosy. The acquired form of HLH is mainly caused by infections (including various viruses, bacteria, fungi, and parasites), drugs, malignancies, and autoimmune diseases. Mycobacterium-triggered HLH has been reported in recent times; however, very few cases have been associated with leprosy. HLH is a rapidly fatal condition with a mortality rate in adults exceeding 50%. Unless an early diagnosis is made and prompt intervention with high-dose steroids and immunoglobulins is undertaken, the mortality rate remains high. Furthermore, the clinical presentation of HLH often coincides with primary sepsis, leading to the withholding of immunosuppressants, which further aggravates the condition. Early diagnosis and prompt intervention in this rare condition are essential to prevent mortality. We describe a case of lepromatous leprosy in a type II reaction on multibacillary-multi-drug therapy treatment, with an unusual, complicated course, characterized by unexplained persistent fever, organomegaly, bicytopenia, and elevated levels of inflammatory markers.