Unusual causes of reactive arthritis: Leptospira and Coxiella burnetii.

Reactive arthritis is a well-defined clinical syndrome occurring after various infections, although most cases are usually associated with Chlamydiae and gastrointestinal pathogens. Its immunologic background has been extensively studied, as has its relationship with HLA-B27. We describe two cases of reactive arthritis arising after infections with two pathogens not so far related to the occurrence of reactive arthritis: one patient exhibited migratory oligoarthritis shortly after the course of acute Q fever, and another patient developed monoarthritis during recovery from leptospirosis. Arthritis was transient and did not exhibit a chronic course in either patient. We further discuss the context of pathophysiology of the arthritis in these patients, with an emphasis on the immunomodulatory properties of these two pathogens.