This case report describes the clinical course of a 3-month-old female with Kawasaki Disease (KD) who presented with intravenous immunoglobulin (IVIG) resistance and coronary artery aneurysm (CAA) complications. Following initial IVIG treatment at an outside hospital, the patient exhibited persistent inflammation and rapid progression of CAA, prompting referral to our institution. Infliximab, an anti-tumor necrosis factor (TNF)-alpha inhibitor, was administered, resulting in rapid improvement of inflammatory markers and CAA dimensions within five days. While there is currently no clear guidance on second-line treatment in refractory KD cases, a second dose of IVIG has generally been used. However, this case exemplifies the efficacy of infliximab in rapidly reducing inflammation and CAA risk, aligning with emerging evidence supporting the use of infliximab in cases resistant to initial IVIG treatment. This is notable, given the scarcity of clear guidelines for second-line treatment in refractory cases, particularly in infants. Early intervention plays a critical role in altering the disease course, underscoring the need for timely and appropriate treatment in high-risk KD patients

Keywords: Infliximab; Kawasaki disease; IVIG resistance; Refractory Kawasaki disease; Coronary artery aneurysm