Opinion statement
Classically, hypersensitivity reactions to iodinated contrast media (ICM) have been termed pseudoallergic, allergy-like, or anaphylactoid. The origin of these terms to define ICM hypersensitivity reactions could be in relation to the use of traditional, classic, ionic ICMs. These ionic ICMs have a high osmolality, and the reactions have been considered as secondary to non-specific histamine release. Currently, ionic ICMs have been replaced by non-ionic compounds with low or iso-osmolality, which, although to a lesser extent, can also produce hypersensitivity reactions. In recent years, there has been growing evidence that some of these reactions, especially the more severe, can be triggered by an IgE-dependent mechanism. Also, in recent decades, there has been an increase in non-immediate reactions, especially in the form of maculopapular exanthems occurring up to several days after the administration of ICM. In these non-immediate reactions, the involvement of T lymphocytes has been clearly demonstrated. The finding of positive skin tests and other in vitro studies for ICMs would support a specific immunological mechanism in a percentage of ICM-induced reactions. However, although there is a body of evidence suggesting that ICMs can induce true allergy reactions, the main guidelines for contrast media management, such as those proposed by US (American College of Radiology Manual on Contrast Media) or European (European Society of Urogenital Radiology Guidelines on Contrast Media) societies, continue to consider only immediate reactions and handle them as non-allergic reactions, without any allergy testing. In ICM reactions an allergic evaluation should be mandatory, not only to study the possible mechanisms involved but also to identify the ICM involved in the reaction and to find an alternative one that could be used in future radiological explorations.
from #ORL-AlexandrosSfakianakis via ola Kala on Inoreader http://ift.tt/2FSVvBj
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