Initial gastrointestinal symptoms might confuse the clinical pictures of some patients with Kawasaki disease (KD) and delay diagnosis and treatment, especially when the patient does not fulfill sufficient diagnostic criteria for KD. Here, we present the case of a 4-year-old boy with KD who complained of severe left abdominal pain and fever alone for the first 6 days. Abdominal ultrasonography showed severe wall thickening localized to the sigmoid colon, and these findings were confirmed by computed tomography and colonoscopy. Microscopic examination of a biopsy specimen revealed non-specific colitis with inflammatory cells in the lamina propria of the sigmoid colon, indicating sigmoid colitis. He subsequently exhibited typical symptoms of KD and was successfully treated with oral administration of aspirin. We suggest that KD should be considered as a differential diagnosis in any child presenting with abdominal symptoms and prolonged fever without definable cause. Abdominal ultrasonography can help evaluate the gastrointestinal complications of KD.
Keywords: Abdominal pain; Kawasaki disease; Sigmoid colitis; Ultrasonography.