Delayed adverse reactions to iodinated contrast media and their risk factors

The present prospective survey was performed to obtain information on delayed adverse reactions (DARs) to five types of low-osmolar iodinated contrast media, including their frequency, common manifestations, and the patient's history of allergy.

We investigated data from 15,890 consecutive patients who underwent contrast-enhanced computed tomography (CT) during a 15-month period. All patients were given a questionnaire asking about the occurrence of DARs, their symptoms and duration, and asked to consult a dermatologist if they had a skin reaction.

Of 11,121 patients who returned the questionnaire (response rate, 70.0%), DARs were observed in 1,058 patients (9.5%). DARs tended to occur with higher incidence in patients with no previous history of examinations using contrast media, with past adverse reactions caused by contrast media, with a history of allergy, or with a serum creatinine level greater than 2.0 mg/dl. Among the 331 patients who reported skin reactions, 41 patients consulted a dermatologist. Skin reactions were observed significantly more frequently in patients for whom iotrolan was used, and 60% of these reactions were severe or moderate.

Four risk factors for DARs were identified in the present investigation.