Acalculous Cholecystitis From Kawasaki Disease in a Three-Month-Old Girl: A Rare Sign at an Uncommon Age.

We report a case of a previously healthy three-month-old girl who presented with acute fever, watery diarrhea, and right upper abdominal guarding. Abdominal ultrasonography findings were compatible with acute acalculous cholecystitis. Initially, antibiotics were administered for a total of eight days without improvement. Hence, atypical Kawasaki disease (KD) was suspected despite the absence of classical disease manifestations and her uncommon age. The diagnosis was made using alternative diagnostic criteria and echocardiography. After KD was diagnosed, high-dose intravenous immunoglobulin G and aspirin were administered on day 9 of disease onset. Her clinical condition significantly improved within 24 hours, and she recovered well without complications during the 1.5 years of follow-up.