[Is there a role for parasites in the etiology of inflammatory rheumatism?]

Parasitic rheumatism is a rare condition characterized by inflammatory joint manifestations due to a parasitic infestation without parasites into joint cavity, (but, with circulating immune complexes, in serum, and synovial fluid; and with immunoglobulins and complement deposits in synovium in some cases reported in the literature). The number of parasites (now 15) which can induce such an arthritis by immune mechanisms is steadily increasing. In all, but few cases of parasitic rheumatism, usual parasitic manifestations (diarrhea, abdominal pain, nausea...) are mild or absent; but, if present, they are a very good criteria to evoke the diagnosis. Clinical pictures of arthritis induced by parasitic infestation are very polymorphic, and non specific of the involved parasite; they seem to depend on genetic predisposition: the symptoms are monoarticular, pauciarticular, or polyarticular, involving small, medium, and or large joints. They can mimic the clinical picture of different inflammatory rheumatic diseases. The most striking feature of parasitic rheumatism is the failure of antirheumatic agents (especially non steroidal anti-inflammatory agents), contrasting with the dramatic efficacy of specific anti-parasitic treatment. The proof of the responsibility of parasitic infestation by indirect mechanism is given by an exceptional case report of a patient with arthritis, dramatically cured after removal of larvae from Anisakiasis gastric granuloma. To explain the uncommon occurrence of this variety of reactive arthritis, due to parasitic infestation, despite the high prevalence of parasitic infestation in the world, hypothesis of genetic predisposition seems valuable. Among 34 well documented reported cases of parasitic rheumatism in the literature, HLA B 27 antigen has been researched in 13; out of these 13, HLA B 27 is absent in 9; in 7 out of these 9, clinical picture is symmetrical polyarthritis. Out of the 13 cases, HLA B 27 is present in 4: In all these 4 cases, clinical picture is asymmetrical pauciarthritis, mimicking arthritis of Reiter's disease.