Reactive arthritis associated with prolonged cryptosporidial infection.

In contrast to arthritic disease caused by different bacterial agents, reactive arthritis due to parasitic infection is rare. We report on an 8-year-old immunocompetent boy with a symptomatic intestinal cryptosporidiosis over a 13-months period. The protozoan infestation was accompanied by arthritic symptoms involving several joints at different times (migratory arthritis). Symptoms resolved spontaneously after 20 months in parallel with stool samples negative for cryptosporidia.