Hypersensitivity To Multiple Iodinated Contrast Media: A Serie Of Cases

RATIONALE: Hypersensitivity reactions to iodinated contrast media (ICM) have risen in parallel with an increase in their use, being more frequent nonimmediate reactions (NIR) than immediate ones. Drug Provocation Test (DPT) is useful not only for diagnosis, but also to test for a safer alternative ICM. Our aim was to describe patients who developed NIR to several ICM.

METHODS: We described 7 patients confirmed as having NIR to ≥3 ICM. They underwent intradermal tests (ID) with reading at 48hs to iomeprol, iohexol, iodixanol, and iobitridol, and DPT with the ICM which gave negative ID by incremental doses in 2 separate sessions with a gap of at least 7 days: 30ml of cumulative dose achieved on first day and 100ml on second day.

RESULTS: Patients median age was 67.4 (58-75)y-old; 5 of them experienced maculopapular exanthema and 2 urticaria 10.3 (6-12)hs after ICM administration. ID was positive to ≥2 ICM (2 to iomeprol, 3 to iodixanol and 4 to iohexol) in 4 patients and negative to all ICM tested in 3 patients. All patients reacted in DPT to ICM which gave negative results in ID (3 to iomeprol, 3 to iodixanol and 6 to iobitridol). Symptoms appeared after 21.5 (6-48)hs of administration of a median cumulative dose of 22 (15-30)ml.

CONCLUSIONS: Although negative ID, tolerance to an alternative ICM must be proved by DPT because some patients may be hypersensitive to several of them. DPT must be performed in 2 separate sessions due to patients often react after ≤30ml cumulative dose of ICM.