[Juvenile idiopathic arthritis and Lyme disease: a case report].

Lyme disease is a systemic infection due to Borrelia burgdorferi. Joint involvement in children, when primary phase is unknown, can be confounded with juvenile idiopathic arthritis. We report a case of a 16 years old girl, who developed at the age of 14 a bilateral and symetrical polyarthritis of big and small joints with fever and cutaneous eruption of trunk. No clinical improvement was seen under disease modified treatment. More biological investigations were performed, leading to the diagnosis of Lyme disease. Clinical recovery was obtained under adapted antibiotherapy, Hence Lyme serology must be performed when atypical polyarthritis appears in a child especially in an endemic region of borrelia burdogferi.