Secondary Hemophagocytic Lymphohistiocytosis due to Anaplasmosis; When Infection meets Hyper-Inflammation: Consider Adjuvant Dexamethasone

Hemophagocytic Lymphohistiocytosis (HLH) is a rare, life-threatening hyper-inflammatory condition characterized by excessive immune activation and multi-organ dysfunction.HLH can be inherited (primary HLH) or acquired (Secondary HLH) due to autoimmune disorders or infections.We report a case of a 72-year-old woman who developed sepsis with HLH features secondary to Anaplasma phagocytophilum infection.Despite appropriate antimicrobial therapy with doxycycline, she experienced rapid clinical deterioration necessitating intensive care and vasopressor support.Adjunctive treatment with a short course of intravenous dexamethasone was associated with marked clinical improvement, resolution of vasopressor dependence and recovery of organ function.This case highlights the importance of early recognition of MAS in infectious contexts and supports consideration of corticosteroid therapy alongside antimicrobials in selected patients.