Background: Hemophagocytic lymphohistiocytosis (HLH), is a potentially fatal hyperinflammatory syndrome characterized fever, hepatosplenomegaly, and cytopenias. HLH can be either primary, with a genetic aetiology, or secondary, associated with malignancies, autoimmune diseases, or infections. Among rheumatic disorders, HLH occurs most frequently in systemic juvenile idiopathic arthritis.
Aim: To draw attention on this severe syndrome that may often go undiagnosed in patient with rheumatic diseases.
Materials and methods: PubMed search was performed by combining the terms (haemophagocytic, haemophagocytosis, hemophagocytosis, hemophagocytic, erythrophagocytosis, macrophage activation syndrome) and (rheumatic, rheumatologic, arthritis, lupus, Sjögren's syndrome, scleroderma, polymyositis, dermatomyositis, polymyalgia rheumatic, mixed connective tissue disease, polychondritis, sarcoidosis, polyarteritis nodosa, Henoch-Schönlein, serum sickness, wegener's granulomatosis, giant cell arteritis, temporal arteritis, Takayasu's arteritis, Behçet's syndrome, Kawasaki, Buerger's).
Results: 117 papers describing 421 patients were considered. HLH was described in systemic lupus erythematosus in 94 patients, in Still's disease in 37 patients, in rheumatoid arthritis in 13 patients, in systemic juvenile arthritis in 219 patients, in dermatomyositis in 7 patients, in Kawasaki disease in 25 patients, in systemic sclerosis in 5 patients, in Behcet disease in one patient, in polyarteritis nodosa in 6 patients, in ankylosing spondylitis in 2 patients, in mixed connective tissue disease in one patient, in sarcoidosis in 5 patients, in Sjögren's syndrome in 3 patients, in Wegener's granulomatosis in one patient, and in unclassifiable disorders in two patients.
Conclusions: HLH occurring in the course of rheumatic diseases is an important and often underdiagnosed clinical entity, which can affect prognosis.