556 Frequency of Positive Skin Test for Iodinated Contrast in Outpatient Clinic of Allergy in Rio De Janeiro, Brazil

BACKGROUND: Adverse reactions to iodinated contrast agents (IC) can be related from a mild to life-threatening event. This frequency varies from 0.2 to 12.7% depending on the type of IC used. Some studies suggest that these reactions may be related to an IgE-mediated mechanism. METHODS: Retrospective study of medical records from patients attended from January 2008 to June 2011 with suspected history of, or risk factors for, reactions to IC. Patients underwent SPT with undiluted IC iopromide used histamine and saline as controls. In those with negative tests were performed intradermal tests with 0.02 mL of IC diluted with saline 1:10. The sample was also evaluated in relation to age, sex, comorbidities, presence of atopy and previous reactions to IC (PRIO). Descriptive statistical analysis of data was performed. RESULTS: We analyzed 27 patients (22 F, mean age: 55.2 years ± 17.4 SD; 59% were atopics). Only one patient (F, 37 years with allergic rhinitis) without PRIO showed positive reaction to intradermal test (3.7%). Five patients (18.51%) with PRIO had negative SPT. CONCLUSIONS: IgE-mediated immune reactions are not common for IC. However, when present contraindicates the use of the compound used in skin testing or other composed of the same pharmacological class. Although the skin tests for IC are not yet fully standardized, its performance can be useful to guide both the patient and the radiologist.