[Anaphylactic shock from an iodine contrast medium: role of the allergy check-up in one case]

Anaphylactoid reactions to iodine contrast media are rare but serious, possibly life-threatening and calling an appropriate and urgent care. The physiopathological mechanism of these reactions remains to be fully elucidated. This reaction is still mostly called "pseudoallergic" in the literature. However, recent papers emphasise that a true allergic process is more frequent than previously expected. They also insist on the interest of running allergy tests including skin testing. We report the case of an anaphylactic shock to iodine contrast media, occurring during coronary angiography. We performed an allergy check-up and found the culprit allergen. We also evidenced a cross-reaction to another contrast media from the similar group. On the other hand, there was no reaction to contrast media of other types. With these results, another coronary angiography could be performed without any adverse event. When hypersensitivity reactions to iodine contrast media occur, it is mandatory to perform a complete allergy check-up. This will help determine the precise mechanism of the reaction and find the culprit allergen.