D3.77 - Hypersensitivity Reactions to Iodinated Contrast Media: A Single-Center Experience

Iodinated contrast media (ICM) are frequently used in diagnostic and interventional imaging, although they may cause hypersensitivity reactions (HSRs), ranging from mild to severe. Immediate hypersensitivity reactions (IHRs) typically occur within an hour of exposure and affect 0.5% to 3% of patients receiving low-osmolar, non-ionic ICM, with anaphylaxis occurring in 0.01% to 0.04% of patients. Non-immediate hypersensitivity reactions (NIHRs), which are primarily T-cell mediated, may occur in up to 23% of patients. Identifying risk factors, effective diagnostic methods, and safe re-exposure strategies is crucial for improving patient safety and enabling re-exposure.

A retrospective cohort study was conducted at Sheba Medical Center between 2019 and 2024, including patients with documented ICM-induced hypersensitivity reactions. Skin testing and drug provocation tests (DPT) were performed to assess the hypersensitivity reactions and identify safe alternative agents.

In our cohort of 85 patients, 49/85 (57.6%) presented with IHRs, of which 11/49 (23%) had positive skin tests. Immediate skin sensitization correlated with anaphylaxis compared to non-anaphylactic reactions (67% vs. 10%, respectively; p = 0.0009, OR = 18.15, 95% CI: [1.79, 3.99]). Among patients with NIHRs (34/85, 40%), appropriate skin sensitization was more frequent in severe cutaneous adverse reaction (SCAR) cases compared to non-SCAR cases (86% vs. 15%, respectively; p = 0.001, OR = 5.81, 95% CI: [0.68, 2.84]). DPTs using non-culprit ICM were successful in 93%–100%, while re-exposure to the culprit agent resulted in recurrent reactions in 50% of patients.

ICM hypersensitivity continues to be a significant clinical challenge despite the use of low osmolar/non ionic agents. Skin testing and DPT are valuable tools in identifying safe alternatives, especially following severe reactions. A structured approach that incorporates allergic evaluation, careful selection of alternative agents, and cautious re-exposure protocols is beneficial and enables further use of ICM.