Immediate hypersensitivity to contrast agents

Immediate hypersensitivity to contrast agents The diagnosis of immediate hypersensitivity reactions to contrast material (CM) relies on a triad associating the description of the clinical signs and their onset delay, the results of the biochemical measurements of plasma histamine and tryptase, and the results of skin testing with the administered CM. The analysis of these data allows identification of the mechanism of the reaction (allergic or non-allergic hypersensitivity) and of the responsible agent. Allergic hypersensitivity to a given CM imposes its definitive avoidance. Skin cross-reactivity with other CM should be investigated in order to propose a non-reactive CM for further procedures. The terms "iodine allergy" should be ruled out, as the iodine atom itself is not responsible for these reactions. Pretreatment protocols do not prevent the occurrence of severe allergic reactions to CM.