We present a case of Kawasaki syndrome complicated by coronary aneurysm in a 6-year-old boy with laboratory evidence of group A streptococcal infection and infectious mononucleosis. The case demonstrates that evidence of acute infection in a patient with features suggestive of Kawasaki syndrome should not exclude a diagnosis of the latter. Immunoglobulin therapy should be considered seriously in highly suggestive cases, even if diagnostic criteria are not fulfilled.
