[Eruptive fever of rare cause: familial hemophagocytic lymphohistiocytosis].

Background: Clinical onset of familial lymphohistiocytosis is non-specific so that the diagnosis of this rare and severe disease is difficult.

Case Report: An 8 week-old girl was admitted suffering from fever and rash. She had hepatosplenomegaly. She developed pancytopenia (Hb: 6.6 g/100 ml; WBC: 4500/mm3; platelets: 25,000/mm3) impaired liver function tests (prothrombin: 15%, blood bilirubin: 40 mg/l; SGOT: 160 mU/ml) and hypofibrinogenemia (0.3 g/l) within a few days. Bone marrow examination showed diffuse histiocytic infiltration and erythrophagocytosis, suggesting a syndrome of inappropriate macrophage activation. The age of the patient, parental consanguinity and absence of specific infection led to diagnosis of familial erythrophagocytic lymphohistiocytosis. The patient died 18 days after clinical onset.

Conclusion: The diagnosis of this unusual syndrome in infants is strongly supported by parental consanguinity as seen in our case or a positive family history. In this condition, erythrophagocytosis is often a marked feature.