Beyond enteric fever: a rare case of Salmonella paratyphi-triggered hemophagocytic lymphohistiocytosis

Infection-associated hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening hyperinflammatory syndrome. We report on a case of 20-year-old female presenting with fever, vomiting, severe diarrhea, and ascending paralysis. Investigations revealed profound hypokalemia, pancytopenia, splenomegaly, elevated inflammatory markers, and fulfillment of HLH criteria. Blood culture confirmed Salmonella paratyphi A infection. She received intravenous ceftriaxone, high-dose dexamethasone, and supportive care following which patient improved symptomatically and laboratory investigations showed resolution of cytopenia, hypokalemia and declining trend of inflammatory markers. This case emphasizes that Salmonella paratyphi although rare could be a trigger for HLH. Early diagnosis and prompt immunomodulatory therapy are crucial in preventing HLH-related morbidity and mortality. Remarkably, full clinical remission was achieved with targeted antimicrobial therapy and dexamethasone alone in our patient, eliminating the need for the traditional etoposide-based triple regimen. This highlights that, when the infectious trigger is swiftly controlled, a focused dual-drug strategy can provide comparable efficacy to traditional regimens.