Incidence and treatment of hemophagocytic lymphohistiocytosis in hospitalized children with Ehrlichia infection.

We report a large cohort of pediatric patients with human monocytic ehrlichiosis (HME), enabling an estimated incidence of secondary hemophagocytic lymphohistiocytosis (HLH) in hospitalized children with HME. Among 49 children with PCR-confirmed Ehrlichia infection, 8 (16%) met current criteria for HLH. Those with HLH had more significant hematologic abnormalities and longer durations from symptom onset to admission and definitive anti-infective therapy. Among these eight, three received chemotherapy plus doxycycline, one of whom died; the other five were treated with doxycycline without chemotherapy, and all survived without HLH recurrence. Our findings demonstrate that antimicrobial therapy alone can successfully resolve Ehrlichia-associated HLH.