Abstract No. 471 Allergy testing for verification of contrast allergy prior to radiology procedures

Abstract

Allergy to contrast material can limit the diagnostic and therapeutic options for patients, especially if the reaction to contrast media is listed as anaphylaxis (IgE-mediated allergic reactions). Many patients with physiologic response to contrast are labeled as being allergic to contrast because the patient or caregiver do not understand the differences between dose-related responses and allergy. Other patients with a history suggesting only a mild reaction may be at risk for anaphylaxis. Our goal is to provide appropriate documentation for the existences or lack of contrast allergy which facilitate best therapeutic and diagnostic options for the patient. Pre-procedure patients with written documentation of contrast allergy were, at the discretion of a licensed independent practitioner, referred to the Allergy and Immunology department for contrast media testing. Patients were tested using an established protocol. Based on reaction clinical history and skin testing patients were classified into four groups: Nonallergic (Negative skin testing, and negative clinical evaluation), predominantly histamine mediated reaction (Negative skin testing, clinical evaluation consistent with histamine mediated symptoms), allergic- like reaction (Negative skin testing, convincing clinical allergic-like reaction), and IgE- mediated allergic reaction (Positive skin testing and positive clinical history) Ten patients completed contrast allergy testing. Referral to allergy and immunology changed the management as follows: avoided steroids in 8/10 (80%) and avoided premedication completely in 6/10 (60%). The testing also confirmed IgE mediated reaction to contrast (Risk of anaphylactic reaction) in 1 patient (10%). Testing in this preliminary patient population suggests significant clinical benefit from referral to allergy and immunology for contrast media testing in patients with reported contrast allergy. Standardization of patient testing may reduce procedure cancellations, excessive use of steroids and potentially the risk of contrast induced anaphylaxis.