Lyme arthritis presenting as adult onset Still's disease

Lyme disease and adult onset Still's disease share several clinical characteristics such as fever, lymphosplenomegaly, skin involvement, and arthritis. Borrelia burgdorferi has been recognized as the cause of Lyme disease and an infectious agent has been suspected, at least as triggering factor, in adult onset Still's disease. This work is concerned with a patient affected by atypical Lyme disease originally diagnosed as adult onset Still's disease. B. burgdorferi infection must be suspected in cases of arthritis suggestive of adult onset Still's disease.