When do adverse reactions to intravascular iodinated contrast material usually occur?
Most reactions to intravascular iodinated contrast occur within 1 hour of intravenous administration. However, delayed adverse reactions may occasionally occur between 1 hour and 1 week following contrast administration. Such delayed reactions are seen more commonly in young adults, women, and patients with a history of allergy, are most commonly cutaneous (e.g., urticaria, rash, or angioedema), and are typically mild to moderate in severity and self-limited. The incidence of delayed allergic-like reactions has been reported to range from 0.5% to 14% and may occur more commonly with iso-osmolal dimeric contrast agents.