Phenotyping allergic patients and evaluating a protocol with rapid
provocation tests with iodinated contrast media
Abstract
BACKGROUND Provocation-tests with contrast media are not standardized,
and our main objective was to evaluate a rapid provocation-test,
including patients with a history of anaphylaxis. As secondary
objectives, we phenotyping our population and proposed a predictive
methodology for the outcomes of allergy tests. METHODS An allergy study
using iohexol, iodixanol, ioversol, and iobitridol was conducted in
patients over 18 years of age with previous hypersensitivity reactions
to iodinated contrast media. A rapid provocation-test (100 cc
administered in 12 minutes) was performed using a non-involved iodinated
contrast medium that had tested negative on skin tests. A statistical
analysis was carried out, including binary logistic regression and
cluster analysis. RESULTS A total of 130 patients were enrolled.
Ninety-six patients (74%) showed cutaneous symptoms exclusively, while
17 patients (13%) experienced anaphylaxis. Nine patients (7%) had
positive skin-tests, and 20 of 141 provocation-tests performed were
positive, all exhibiting mild cutaneous symptoms, including in those
with a history of anaphylaxis. A safe alternative contrast medium was
recommended to 122 patients (94%), with good tolerance in 50 patients
who required a new radiological examination. We identified three patient
phenotypes, each associated with a different risk of a positive drug
provocation-test. A predictive model for the outcomes of allergy tests
was obtained, but it exhibited a low predictive capacity. CONCLUSIONS We
confirm the efficacy and safety of a protocol including rapid
provocation-tests in patients with hypersensitivity reactions to
iodinated contrast media of varying severity. Three patient clusters
were identified, each showing a different risk level for a positive
provocation-test.