The value of low dose provocation test in the diagnosis of non-immediate iodinate contrast media hypersensitivity

Abstract

Background: Iodinated contrast media enhance the visibility of vascular structures and organs during radiographic procedures. Although generally considered safe, it is the third leading cause of cutaneous drug reactions. Iodinated contrast media is one of the most frequently used drugs in diagnostic medicine, but non-immediate hypersensitivity reactions are believed to be underreported because of delayed onset, which makes recognising and diagnosing these reactions challenging. For this reason, it is important to raise awareness about non-immediate hypersensitivity reactions to iodinated contrast media in the medical society. Case Reports: We present two case reports of non-immediate hypersensitivity reaction to iodinated contrast media after the first exposure. Patient I reacted to iohexol and iopromide with fixed drug eruption. Patient II reacted to iodixanol with a maculopapular rash on the chest and abdomen, Quincke’s oedema in her face and neck. Both patients had negative skin testing (prick, intradermal and patch test), but drug provocation test confirmed the allergy to iodixanol for Patient II. Patient I underwent premedication before re-exposure to iodinated contrast media, but it was unsuccessful. Histological examination of eruptions of both patients showed dermatitis, usual for drug hypersensitivity. Conclusion: In this article, we demonstrate the importance of drug provocative test as well as limitations of skins tests and premedication