Hypersensitivity Reactions to Iodinated Contrast Media

Abstract

Adverse reactions after iodinate contrast media (ICM) administration have been observed, which can be classified as immediate (i.e., occurring within one hour after administration) and delayed or non-immediate (i.e., occurring more than one hour after administration). Even though the incidence of ICM adverse reactions has been significantly reduced by the introduction of non-ionic compounds, immediate reactions still occur in about 3% of administrations. Different pathogenic mechanisms have been suggested for ICM reactions, including immunologic ones. Basophils and mast cells participate in immediate reactions through the release of mediators like histamine and tryptase, whereas a T-cell-mediated pathogenic mechanism is involved in most non-immediate reactions, particularly maculopapular rashes. Skin tests and specific IgE assays are carried out to diagnose immediate hypersensitivity reactions, while both delayed-reading intradermal tests and patch tests are usually performed to evaluate non-immediate reactions. However, in vitro specific IgE assays are not commercially available. As far as in vitro tests are concerned, a response involving ICM-related T-cell activity may be assessed by the lymphocyte transformation test. Allergologic evaluation appears to be indicated in hypersensitivity reactions to ICM, although the sensitivity, specificity, and predictive values of allergologic tests have not yet been established. This paper summarizes the current state of the art and addresses the research that is still needed on the pathogenic mechanisms, diagnosis, and prevention of ICM-induced hypersensitivity reactions.

Late adverse reactions to intravascular iodine based contrast media: an update

“…They were reviewed by the Contrast Medium Safety Committee (CMSC) of the European Society of Urogenital Radiology and guidelines were published in 2003 [2,3]. Since then, there have been new insights into the pathophysiology of late skin reactions and a number of prospective studies of late adverse reactions and overviews of the subject have been published [4][5][6][7][8]. It was therefore decided to review the literature again by checking repeatedly two databases (PubMed, Web of Science) for papers published from 2003 to October 2010.…”

“…Several investigators have shown positive patch and/or delayed-reading intradermal tests to the culprit iodine based contrast medium in subjects with late skin reactions [7,37,40,41]. About 50% of patients also reacted to structurally similar contrast media [23,42,43].…”

Patch Testing in Non-Immediate Drug Eruptions

“…Several investigators have shown positive patch and/or delayed-reading intradermal tests to the culprit ICM in subjects with non-immediate reactions to ICM [34-36]. In particular, positive delayed-reading skin tests and/or patch tests for the responsible compound have been found in about 100 patients with ICM-induced late-onset skin reactions.…”

Hypersensitivity Reactions to Contrast Media: Prevalence, Risk Factors and the Role of Skin Tests in Diagnosis – A Cross-Sectional Survey

“…Adverse reactions after CM administration have been divided into 3 types, namely allergic and nonallergic hypersensitivity reactions, toxic reactions and reactions unrelated to CM application [11]. Hypersensitivity reactions after exposure to CMs are classified according to the time interval between CM administration and the first appearance of clinical manifestations as immediate (reaction within 1 h) and nonimmediate reactions (reaction after 1 h).…”