Hypersensitivity reactions to iodinate contrast media in Italy: a retrospective study. Characteristics of patients and risk factors.

SUMMARY: 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.

Suspected acute allergic reactions: analysis of admissions to the Emergency Department of the AOU Maggiore della Carità Hospital in Novara from 2003 to 2007.

OBJECTIVE OF THE STUDY: The aim of our work is to ascertain the frequency and the impact of acute allergic reactions on the routine of a highly-specialized Emergency Department collecting information on the admission, the typology of symptoms and the degree of severity calculating the incidence and the outcomes of the events. MATERIALS AND METHODS: The study started the 1 July 2006 and the records of the Emergency Department of the Maggiore della Carità Hospital in Novara were consulted retrospectively in the period between the 1 January 2003 and the 31 December 2006, and prospectively up to the 31 December 2007, using keywords that could identify admission for suspected allergic reactions. Information relating to internal medicine and/or pediatric cases were examined, excluding all surgical and/or trauma cases. The number ofadmissions per year was considered broken down by clinical signs, triage assessment upon admission and discharge outcome. RESULTS: Admissions to the Emergency Department during the period under consideration were 165,120 with 6107 suspected cases of allergic reactions. The symptoms most frequently reported both in adults (A) and children (C < or =18 years old), were: hives 37%, asthma 20.65 (A)% and 27.4% (C); drug allergy 7.5% (A) and 6.1% (C). Reactions to Hymenoptera venom were less frequent, 4.7% (A) and 1.27% (C); the frequency of angioedema, conjunctivitis and rhinitis was between 1 and 4%. The incidence of food allergies (1.4%) and anaphylaxis (0.8%) was comparable for all ages. The triage assessment showed a significant percentage of "yellow" and "red" codes, with 362 cases (5.9%) and 71 cases (1.16%) respectively. A total of 151 patients was hospitalized, no one classified as "white" code. Death occurred in 7 cases: 4 "yellow" codes and 3 "red" codes, respectively. A more detailed specialistic evaluation was recommended in only 10% of the patients. CONCLUSIONS: Admissions to the Emergency Department for suspected allergic reaction are proportional to the number of overall admissions for internal medicine cases and do not appear to be related to the general increase of allergies in the population. This led us to focus our attention on how allergic diseases impact the work of an Emergency Department and how to describe the discharge diagnosis better. A significant number of descriptive diagnoses also turned out to be inaccurate and did not allow the syndrome to be identified properly. The analysis of this information aims to be a stimulus to improve the emergency clinical approach used for allergic diseases and to plan the adequate management ofallergic patients after they have been treated in hospital.