Recent updates of iodinated contrast media hypersensitivity

ABSTRACT

Previously, immediate reactions to ionic high-osmolar iodinated contrast media (ICM) were regarded as nonimmunological. However, despite the use of lower-osmolar ICM, ICM hypersensitivity still occurs in some patients and recent studies suggest that there would be a true allergic response, especially in more severe form. Currently, it is important to identify the sensitized ICM and avoid the agent; however, the usefulness of skin tests and challenge tests has not yet been established, since there are few large-scale studies on them. Although, skin test-negative ICM can be safely used in clinical practice, conflicting results have been reported through various studies, depending on the challenge protocols used. Therefore, standard protocols need to provided. Even if a culprit agent is not proven by skin tests, its use should be avoided. Reuse of contrast media increases the risk of occurrence of hypersensitivity reactions. For patients with previous hypersensitivity reactions to contrast media, premedication can help prevent recurrence, but breakthrough in hypersensitivity is not fully achieved by premedication, especially when the previous reaction was a severe form such as anaphylaxis. Therefore, it is necessary to establish an optimal strategy to choose alternative ICM and premedication protocols to prevent recurrence of hypersensitivity reactions to nonionic contrast media.