Safe rechallenge with alternative intravenous immunoglobulin after the development of severe hypotension in an infant with Kawasaki disease

Intravenous immunoglobulin (IVIG) is the first-line therapy for Kawasaki disease (KD) in children and is generally safe, although severe hypotension or shock has been rarely reported. Recognition and management of such adverse events are important because IVIG remains essential for preventing coronary complications. A 7-month-old girl presented with fever, rash, and clinical features consistent with KD. On day 5, IVIG (freeze-dried sulfonated human normal immunoglobulin, 2 g/kg) was initiated at 0.83 mg/kg/min and increased to 2.5 mg/kg/min. Sixteen minutes after acceleration, she developed a sudden loss of consciousness with cyanosis and absent pulses, consistent with severe hypotension. IVIG was discontinued, and intramuscular adrenaline was administered, resulting in rapid recovery. No other immunoglobulin E-mediated manifestations were observed, and basophil activation testing was negative. Due to persistent fever, an alternative IVIG preparation (polyethylene glycol-treated human normal immunoglobulin, 2 g/kg) was administered on day 7 with premedication at a reduced infusion rate (0.41–0.83 mg/kg/min). Infusion was completed without adverse events, fever resolved by day 8, and the patient was discharged on day 13. Follow-up echocardiography revealed a medium-sized coronary aneurysm. Although IVIG causing severe hypotension in infants with KD is rare, cautious readministration of an alternative preparation with premedication at a reduced infusion rate is advised.