Anaphylactoid reactions and late skin reactions to radiocontrast media: the present state of the question.

Purpose. - Adverse reactions to iodinated contrast media (ICM) share variou s mechanisms. Anaphylactoid reactions are among the most serious reactions when they are characterized by the elevation of seric tryptase. Pretreatmen t with corticosteroids and anti-H1 or the use of non-ionic contrast media d o not prevent anaphylaxis. Late skin reactions could be mostly related to d elayed hypersensitivity. Previous reactions to contrast media, cardiovascul ar disorders, beta-blockers, asthma, and atopy are risk factors. Female gen der and age increase the severity. Current knowledge and key points. - Anaphylaxis can be demonstrated by intr adermal tests and the identification of specific IgEs. Delayed hypersensiti vity is shown by the results of epicutaneous tests and the immunohistology of the skin. Future prospects and projects. - Allergologic tests are advised in the case of previous reactions. In case of emergency, gadopentetate dimeglumine can be alternatively used. The other risk factors lead to the combination of p retreatment and use of non-ionic monomeric contrast media. Immediate hypers ensitivity to iodinated media might increase in the near future with the us e of divalent molecules. (C) 2001 Editions scientifiques et medicales Elsev ier SAS.