Immediate Reactions to Iodinated Contrast Media Prevalence of IgE-mediated Hypersensitivity

Abstract BackgroundAfter administration of iodinated contrast media (ICM) some patients develop an immediate hypersensitivity reaction (IHR). A specific allergic IgE-mediated mechanism may be involved. ObjectiveTo determine the prevalence of allergic patients among ICM reactors and to evaluate the negative predictive value (NVP) of skin testing for ICM.MethodsAll patients who attended a single center for an allergy work-up between 2010 and 2019 due to a prior IHR after an ICM injection were included retrospectively. ICM allergy was diagnosed if prick tests or intradermal tests were positive. Further information concerning secondary exposure to ICM was obtained from all patients with negative skin tests to determine whether ICM re-exposure led to an IHR.ResultsSkin tests identified ICM allergy in 7 out of 85 patients (8.2%). Frequency of IgE-mediated hypersensitivity among patients increased with increasing reaction severity. The NPV of skin testing for ICM allergy was 87.8% [95%CI 75.2;95.4.ConclusionThe low prevalence of IgE-mediated hypersensitivity among patients with IHR to ICM should not delay allergy workup. Earlier skin tests and provocation tests with skin-test negative ICM may help allergists to find a reliable alternative ICM.