Résumé : Hemophagocytic lymphohistiocytosis (HLH) is a rare but severe and potentially fatal syndrome that is characterized by increased proliferation and activation of benign macrophages with hemophagocytosis throughout the reticuloendothelial system. This syndrome is classified as primary (genetic) or secondary when acquired in the context of infections (usually viral), malignancies, rheumatologic and metabolic diseases.