Incomplete Kawasaki disease with coronary artery aneurysms in an infant presenting with persistent fever despite pneumonia treatment

Incomplete Kawasaki disease (KD) in infants often presents without classic clinical features, increasing the risk of delayed diagnosis and coronary complications.We report a previously healthy 9-month-old male who presented to an emergency department with a 15-day history of fever and dry cough, despite amoxicillin therapy for presumed pneumonia.On arrival, the infant was febrile and tachycardic, with stable hemodynamics and a benign finding of physical examination.Laboratory evaluation showed high values of inflammatory markers.The persistent fever and high values of inflammatory markers despite the antimicrobial therapy prompted consideration of incomplete KD as an alternative diagnosis.This diagnosis was confirmed by multiple coronary artery aneurysms shown on an echocardiogram.His fever was resolved by the use of intravenous immunoglobulin, methylprednisolone, and highdose aspirin.This case highlights the importance of maintaining a high index of suspicion for incomplete KD in infants with persistent fever and evolving inflammatory findings, despite appropriate antimicrobial therapy.