Novel Strategy for the Prevention of Recurrent Hypersensitivity Reactions to Radiocontrast Media Based on Skin Testing

Background: Hypersensitivity reactions to iodinated contrast media (ICM) is a persistent clinical issue with increased use of computed tomography. With the evidence indicating underlying allergic mechanisms, there have been studies regarding the skin tests using ICM. Objective: This study aimed to evaluate the intradermal skin test (IDT) as a tool for preventing recurrent hypersensitivity reactions to ICM in patients with prior reactions to a known culprit agent. Methods: Sixty-nine patients who had experienced immediate hypersensitivity reactions to ICM were included in the study. All patients underwent IDT with 7 different ICMs, including the causative ICM. We analyzed clinical data from 38 patients who were reexposed to ICMs, grouped by the IDT results to their original culprit ICM. Results: Thirty-eight patients showed positive IDT results to the culprit ICM (CULPRIT+), whereas 31 patients showed negative results (CULPRIT−). Sixteen patients from the CULPRIT+ group and 22 from the CULPRIT− group were subsequently exposed to an ICM. In the CULPRIT+ group, 4 of the 5 patients who were subsequently exposed to an IDT-positive ICM reexperienced hypersensitivity reactions. When patients were exposed to IDT-negative ICM as an alternative, hypersensitivity reactions were not observed. In the CULPRIT− group, IDT-positive ICMs did not provoke hypersensitivity reactions whereas 2 patients using IDT-negative ICMs experienced hypersensitivity reactions. Conclusions: When the IDT results are positive for the culprit ICM, additional IDTs with other ICMs are needed to select a safe alternative. If the IDT results are negative against the culprit ICM, further IDTs might not play a role in selecting a safe alternative.