Objective. The purpose of the study was to describe the characteristics of patients experiencing hypersensitivity reactions (HRs) to iodinated contrast media (ICM) in a large Italian population and to investigate potential risks factors in order to obtain a risk stratification, helpful in the management of these patients. Methods. Data of 407 patients investigated in 9 Italian Allergy Centers for suspected HRs to ICM were analyzed and compared with a control group of 152 subjects that tolerated one or more ICM-enhanced examinations. The univariate and multivariate logistic regression model was used to evaluate associated factors. Results. The mean age of reactive patients was 61 years and 60% were female; 67% of patients reported immediate reactions and 35% experienced the reaction, more frequently with immediate onset, at the first examination in life. Iomeprol, iopromide and iodixanol were the most frequent culprit agents and 20% of patients showed a positive skin test result. Previous adverse reactions to ICM were reported by 15.6% of patients, whereas 35% of subjects experienced the reaction, more frequently immediate, after the first ICM-enhanced examination in their life. The multivariate analysis showed that male gender and age > 65 were associated with ICM reactions as protective factors [ORadja = 0.51; 95% CI: 0.33-0.77 and ORadja = 0.60; 95% CI: 0.39-0.92 respectively]. Cardio-vascular disease [ORadja = 2.06; 95% CI: 1.22-3.50)], respiratory allergy [ORadja = 2.30; 95% CI: 1.09-4.83)] and adverse drug reactions [ORadja = 1.99; 95% CI: 1.05-3.77)] were identified as risk factors for ICM reactions. Food allergy was not significantly associated with reactions [ORadja = 1.51; 5% CI: 0.41-5.56]. Conclusions. This is the largest study on Italian patients experiencing hypersensitivity reactions to ICM. Most results are in line with other studies, showing some association with factors that could influence the incidence of hypersensitivity reactions but not allowing an easy risk stratification.
