1 - Serviço de Imunoalergologia, Centro Hospitalar Universitário de Lisboa Central, Lisboa
- EAACI Congress 2021, reunião internacional, apresentação sob a forma de E-poster
Introduction: Radiocontrast media (RCM) are concentrated solutions of tri-iodinated benzene derivatives used to the diagnosis and treatment in modern medicine. The increased use of RCM leads to a higher incidence of adverse reactions. These reactions can either be hypersensitivity reactions (HR), toxic reactions, or events unrelated to RCM exposure. HR are classified into immediate reactions (IHR) occurring within 1-6 hours after RCM administration or nonimmediate reactions when starting later. A correct diagnosis of drug HR is very important for both the patient and the health system. However, in some cases, it may remain unclear the pathophysiological process that leads to the HR. IHR were classically considered non-allergic, and the existence of cross-reactivity was controversial. Recent reports show evidence of a possible IgE-mediated mechanism.
Case Report: We present a case of a 41-year-old woman was submitted to a thoracic computerized tomography with radiocontrast for breast neoplasm staging. She had no prior history of drug allergy and was never previously submitted to this exam. The patient only had a history of allergic rhinitis and was not taking any medication. Two hours before the exam, she ingested meglumine Ioxitalamate without any reaction. At the beginning of the exam, she received iomeprol intravenous (IV), and five minutes after administration, she presented with sternutatory crises and generalized heat sensation. The exam was not discontinued, and thirty minutes after its conclusion, she presented with nausea, generalized pruritic maculopapular erythema, and palpebral edema. Symptoms reversed with hydrocortisone and clemastine. Skin tests were performed with multiples RCM, and there was found positivity for both iomeprol and ioversol. These results suggest an IgE-mediated allergy as responsible for the HR and also possible cross-reactivity between RCMs.
Conclusion: HR to RCM are still a challenge and a good clinical history, as well as the event’s report, are of vital importance in achieving a correct diagnosis. Skin tests are recommended as the first step in the diagnostic approach to IgE mediated allergies and could help identify crossreactivity between RCM and provide guidance on tolerated alternatives for future procedures.
Palavras Chave: Drug allergy; radiocontrast media