[Chronic polyarthritis in cystic fibrosis].

In a 8 year-old girl, presenting with cystic fibrosis and severe respiratory failure, a chronic polyarthritis with skin rashes occurred. Rheumatoid factor was lacking in the serum. Antibiotic treatments of the pulmonary infections resulted repeatedly in an improvement of both articular and cutaneous disorders. Thus, the trigger-action of the microbic infection was considered as the inducer of a "reactive arthritis".