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.