Delayed adverse reaction to nonionic contrast agents

Delayed reactions to nonionic contrast agents are not well known. We describe a child with a life-threatening reaction. Conclusions: (1) Late adverse contrast reactions can follow nonionic contrast administration without any immediate reaction; (2) the manifestations may be unusual with symptoms not typically associated with a contrast reaction; (3) the reactions are most often self-limiting and minor, but can be serious; (4) the protective effect of steroid pretreatment, especially same-day intravenous therapy, is uncertain.