Allergy Evaluation and Desensitization Standards for Radiocontrast Media

To the Editor: We reviewed with interest article by Khan et al. outlining their use of rapid drug desensitization (RDD) to radiocontrast media (RCM).1Khan S. Kamani A. Strauss B.H. Zipursky J. Successful coronary angiography following intravenous for refractory contrast Allergy.Can J Cardiol. 2020; 36: 1161.e1-1161.e2Abstract Full Text PDF Scopus (1) Google Scholar While we commend RDD, there are some points that warrant clarification. The term anaphylactoid has been supplanted nonimmunologic or non–IgE-mediated anaphylaxis. Anaphylactoid reactions had perceived as reactions, but current evidence suggests mast cells can be triggered release same mediators through non-IgE mechanisms, either directly other receptors (such complement anaphylotoxins C3a and C5a) others. Mast cell degranulation (MCD) RCM is inducible both IgE and, regardless trigger mechanism, all forms anaphylaxis severe fatal. reaction history suggestive IgE-mediated allergy RCM, skin testing should have done demonstrate sensitization select alternate agents.2Trautmann Brockow K. Behle V. Stoevesandt Radiocontrast hypersensitivity: differentiates from nonallergic identifies a safe alternative proven provocation.J Allergy Clin Immunol Pract. 2019; 7: 2218-2224Abstract PubMed (22) patient’s preceding despite pretreatment likely demonstrates it was not event title indicates. This an important clue nature his allergy, which RDD appropriately undertaken. authors further assert sometimes dose dependent, thereby rationalising administration higher than others cited in literature. In fact, always time supported vitro data.3Sancho-Serra Mdel C. Simarro M. Castells Rapid antigen specific impairs early late responses targeting FcεRI internalization.Eur Immunol. 2011; 41: 1004-1013Crossref (95) total amount exposed during achieve desired therapeutic diagnostic required. Moreover, although agree much learn regarding does induce subclinical histamine depletion. Instead, serves prevent IgE-antigen internalization transmembrane calcium influx, prerequisites MCD.3Sancho-Serra diverts intracellular signalling cascades away those leading degranulation, induces what might comparable cardiomyocyte-like state cell. There no patients would remain desensitized 24-48 hours procedure, because enduring effect influenced individual drug’s half-life. Finally, safety efficacy well established, cardiac patients, owing underlying artery disease and/or coadministration medications such beta-blockers angiotensin-converting enzyme inhibitors (which may resistance epinephrine if required possibly increase severity), represent higher-risk population.4Jakubovic B.D. Vecillas L.L. Jimenez-Rodriguez T.W. Sanchez-Sanchez Drug hypersensitivity fast lane: clinicians know about phenotypes, endotypes, biomarkers.Ann Asthma 124: 566-572Abstract (5) case highlights availability expertise capability offer allows optimal care patient allergy.