A healthy 3-year-old girl presented to an outside hospital with symptoms consistent with respiratory syncytial virus bronchiolitis. On admission, shereceived 30 mg of methylprednisolone succinate and a 300-mL bolus of normal saline through a 22-g intravenous (IV) catheter inserted in the dorsal aspectof the left hand. The normal saline was administered at 150 mL/h for 2 hours and then changed to 5% dextrose in 0.45% sodium chloride solution at 75 mL/h.After 18 hours, blood cultures yielded gram-positive cocci in pairs and chains, and IV ceftriaxone sodium therapy was initiated at a dosage of 50 mg/kg perday. The next morning, blisters were noted on the left elbow just proximal to an IV arm board used to secure the hand catheter. After a second infusionof ceftriaxone, the patient reported extreme pain in her left arm. Her arm was markedly swollen and an allergic reaction was suspected. The catheterwas removed from the left hand, and a cold pack was applied to the dorsal aspect of the hand. Intramuscular diphenhydramine hydrochloride and subcutaneousepinephrine (1:1000) were administered, and the patient was airlifted to a tertiary medical center.