Background Iodinated and gadolinium-based contrast media (ICM; GBCM) induce immediate hypersensitivity (IH) reactions. Differentiating allergic from non-allergic IH is crucial; allergy contraindicates the culprit agent for life. We studied frequency of allergic IH among ICM or GBCM reactors. Methods Patients were recruited in 31 hospitals between 2005 and 2009. Clinical symptoms, plasma histamine and tryptase concentrations and skin tests were recorded. Allergic IH was diagnosed by intradermal tests (IDT) with the culprit CM diluted 1:10, “potentially allergic” IH by positive IDT with pure CM, and non-allergic IH by negative IDT. Findings Among 245 skin-tested patients (ICM = 209; GBCM = 36), allergic IH to ICM was identified in 41 (19.6%) and to GBCM in 10 (27.8%). Skin cross-reactivity was observed in 11 patients with ICM (26.8%) and 5 with GBCM (50%). Allergy frequency increased with clinical severity and histamine and tryptase concentrations (p < 0.0001). Cardiovascular signs were strongly associated with allergy. Non-allergic IH was observed in 152 patients (62%) (ICM:134; GBCM:18). Severity grade was lower (p < 0.0001) and reaction delay longer (11.6 vs 5.6 min; p < 0.001). Potentially allergic IH was diagnosed in 42 patients (17.1%) (ICM:34; GBCM:8). The delay, severity grade, and mediator release were intermediate between the two other groups. Interpretation Allergic IH accounted for < 10% of cutaneous reactions, and > 50% of life-threatening ones. GBCM and ICM triggered comparable IH reactions in frequency and severity. Cross-reactivity was frequent, especially for GBCM. We propose considering skin testing with pure contrast agent, as it is more sensitive than the usual 1:10 dilution criteria.

To date, only a few series have analyzed the long-term outcome of giant cell arteritis (GCA) patients with aortic involvement, which prompted us to conduct the current retrospective study. Our aims were to 1) determine the prevalence of GCA in patients exhibiting nonatherosclerotic aortic involvement (that is, aortitis, aortic ectasia, and/or aneurysm); and 2) evaluate clinical features and long-term outcome of GCA patients exhibiting aortitis, aortic ectasia, and/or aortic aneurysm.From January 1997 to March 2008, 66 consecutive patients in the Department of Internal Medicine at the University of Rouen medical center received a diagnosis of nonatheromatous aortic complications (aortitis, aortic ectasia, and/or aneurysm). In these 66 patients, aortic involvement was related to GCA (n = 48), Takayasu arteritis (n = 6), relapsing polychondritis (n = 1), and infection (n = 11).Of the 48 patients with GCA, aortic involvement preceded the initial GCA diagnosis in 1 patient. Aortic involvement was identified in association with GCA in 40 patients (83.3%), and developed after the onset of GCA in the 7 remaining patients (14.6%). Aortic involvement was more often asymptomatic (77.1%). The aortic helical computed tomography (CT)-scan procedure principally showed isolated aortitis (circumferential thickening of the aortic wall >3 mm) in 41 patients (85.4%). In the remaining 7 patients with GCA (14.6%), aortic helical CT scan demonstrated aortic thoracic ectasia and aortitis (n = 3), aortic thoracic aneurysm and both thoracic and abdominal aortitis (n = 3), and both aortic abdominal aneurysm and aortitis (n = 1). All patients were given steroid therapy at a median daily dose of 1 mg/kg initially.At 6-month follow-up, 34 of 48 patients systematically underwent both thoracic and abdominal CT scan. Aortic helical CT scan demonstrated complete disappearance of aortitis in 8.8% of patients, improvement of aortitis in 47.1%, unchanged pattern of aortitis and/or aortic thoracic ectasia/aneurysm in 41.2%, and deterioration of aortic thoracic aneurysm in 1 patient (2.9%). At 18-month follow-up, 11 patients systematically underwent both thoracic and abdominal CT scan. Aortic helical CT scan showed complete disappearance of aortitis (n = 1), improvement of aortitis (n = 1), unchanged pattern of aortic thoracic ectasia/aneurysm (n = 2), and deterioration of aortic thoracic aneurysm (n = 1). At patients' last follow-up, the median daily dose of prednisone was 7 mg. Steroid therapy could be discontinued in 17 patients (35.4%).The current retrospective study suggests that aortic impairment may be more prevalent than previously reported. Our findings suggest that specific inflammatory thickening of the aortic wall is common at the time of GCA diagnosis, and that aortitis may be the first manifestation of GCA-associated aortic complications. Whether isolated aortitis leads to vascular wall injury responsible for late-onset aneurysmal disease remains to be determined. At this time, we recommend long-term monitoring for aortic aneurysms, espe...