More work needed to standardize reaction documentation to radiocontrast media
Click Here to Manage Email Alerts
LOUISVILLE, Ky. — Radiocontrast media allergies may impede care, but they are not well-characterized, according to a presentation at the American College of Allergy, Asthma & Immunology Annual Scientific Meeting.
“Patients with documented radiocontrast media hypersensitivity reactions may require pretreatment or skin testing prior to obtaining imaging with contrast,” Jenny Huang, MD, a third-year internal medicine resident in the division of allergy, asthma and immunology at Scripps Clinic in San Diego, said in her presentation.
Also, Huang said, pretreatment is not without side effects, and contrast allergies often are incorrectly associated with iodine and shellfish allergies.
Huang and colleagues conducted a retrospective chart review of more than 2 million patients in their health system’s electronic medical record including terms used to indicate radiocontrast media, iodine and shellfish allergies.
They identified 21,745 patients (mean age, 60.52 years; women, n =14,968; white, n = 15,388) with 24,333 qualifying allergies, including 6,752 to radiocontrast media, 7,398 to iodine and 10,183 to shellfish.
Specifically, 19,338 (88.93%) had a single allergy (contrast, n = 5,368; iodine, n = 5,354; shellfish, n = 8,616). The 2,226 patients (10.24%) with two qualifying allergies included 840 with a contrast and iodine allergy, 363 with a contrast and shellfish allergy and 1,023 with an iodine and shellfish allergy. A total of 181 (0.83%) had allergies to all three.
“We obtained data regarding reactions to these allergens and then grouped them into categories,” Huang said.
The cohort reported cutaneous reactions (contrast, 29.04%; iodine, 26.17%; shellfish, 22.18%), anaphylaxis (8.6%; 8.58%; 13.89%), respiratory reactions (2.77%; 2.35%; 2.39%), gastrointestinal reactions (2.71%; 1.85%; 6.26%) and swelling (1.94%; 2.22%; 4.28%), with many patients having no reactions documented (52.99%; 59.25%; 52.7%).
When the researchers examined the records of the 1,384 patients with multiple allergies and documented reactions, 60.7% had overlapping contrast and iodine allergies, 26.2% had overlapping contrast and shellfish allergies and 13.1% had all three allergies.
Overall, Huang noted that only 1% of the health system’s patients had a documented allergy to radiocontrast media, iodine or shellfish.
“With studies estimating that 3.7% to 12.8% of patients have sensitivities to radiocontrast media, medical records may severely underreport patients with radiocontrast media sensitivity,” Huang said.
Huang also said that the approach to care for the 88% of patients with qualifying allergies who only had one of the listed allergies should be clear.
“However, that may not be the case since over 50% of entries did not have a specified reaction documented, making it difficult to know how to approach these patients when they need a study using radiocontrast media,” she said.
Huang and her colleagues called for more research and work to standardize reaction documentation to identify true hypersensitivity reactions compared with adverse reactions and side effects and to prevent unnecessary testing for patients.