Kawasaki disease (KD) is a common form of acute systemic immune vasculitis that affects children. KD primarily affects children under the age of 5; however, it is extremely rare in infants younger than 3 months. KD in infants is often atypical, which makes early diagnosis challenging.Infant patients who are discharged with KD tend to be more likely to develop coronary artery aneurysm (CAA). Whether this increased rate of coronary complications is solely due to delayed diagnoses, and consequently delayed treatment, is not clear. The treatment of KD in infants is similar to that in older children. IVIG and aspirin are used as first-line treatments. For resistant KD patients, additional treatment, such as intravenous infliximab, is needed.we present a case to investigate the efficacy and safety of infliximab in the treatment of refractory Kawasaki Disease (rKD) complicated macrophage activation syndrome（MAS） in infants, and review the literature.

we present a case to investigate the efficacy and safety of infliximab in the treatment of refractory Kawasaki Disease (rKD) complicated macrophage activation syndrome（MAS） in infants, and review the literature.

 A 61-day old infant who manifested as fever, rash, conjunctivitis and raspberry tongue was diagnosed with KD complicated MAS. Due to atypical early manifestations, diagnosis was difficult and treatments were delayed, traditional treatments including Intravenous Immunoglobulin (IVIG) and aspirin did not control the condition. After three times infliximab treatment the disease was controlled. However, local axillary lymph node swelling subsequently occurred, and local BCG infection was confirmed by T-SPOT, lymph node biopsy, and Multiplex pathogen testing. The condition of this patient was improved after anti-tuberculosis treatment.

Early use of biologics therapy such as Infliximab is effective for refractory Kawasaki disease in infants. But young infants, especially those ≤3 months of age, should be alert to the risk of mycobacterium tuberculosis infection after BCG vaccination .