Iodinated Contrast Media and Anaphylaxis.

Immediate hypersensitivity reactions (IHRs) to iodinated contrast media generally occur due to non-immunoglobulin E (IgE)-mediated release of histamine and other inflammatory mediators from mast cells and basophils. IgE-mediated reactions have also been described. Although premedication was previously recommended routinely for prior reactors, based on the substantially lower rate of IHR with low osmolar contrast media, premedication has become controversial as to whether the potential for benefit exceeds the potential for harm. Switching contrast agents, skin testing to contrast agents, drug provocation testing, and rapid drug desensitization are additional risk-reduction strategies that can be considered in properly selected patients.