Skin Tests for the Exploration of Hypersensitivity Reactions Associated with Iodinated Contrast Media

Background: Iodinated contrast media (ICM) are responsible for multiple side effects, especially hypersensitivity reactions. These reactions can either be authentic allergies or non-allergic hypersensitivity reactions. Skin tests (prick and intradermal tests) are simple to perform and can be of great help, especially if the ICM needs to be re-used. The aim of the study was to assess the characteristics of the patients in whom skin tests were performed and the results of these tests. Methods: This is a retrospective study from June 2014 to June 2019. All included patients had at least one episode of hypersensitivity reaction to ICM and underwent skin tests. Results: We included 35 patients aged 18 to 85 years. The iopromide was the most implicated ICM. The reactions were mainly cutaneous (n=30) and immediate (n=27). The skin tests were negative, except for two patients. The re-use of ICM occurred in 11 patients: 9 with an ICM other than the one suspected and two patients with the same ICM. Among these patients, 5 did not have any premedication. Two of them had a second hypersensitivity reaction, the first with another ICM and the second with the same ICM. Conclusion: One of the main pillars of allergic exploration is ICM skin testing, not only to prevent a recurrence, but also to allow patients to benefit from ICM re-use, which are sometimes essential.