Mucocutaneous lymph node syndrome in a young adult.

Mucocutaneous lymph node syndrome (MLNS) is an acute febrile illness of unknown cause first described in Japan but more recently reported in the United States. The mean age in confirmed cases was 3.8 years (range, 3 months to 13 years), and the mortality is 1% to 2% when associated with coronary artery thrombosis and aneurysm. We describe the first case of MLNS in a young adult, with the additional clinical finding of associated arthritis.