Image: A new study suggests that allergic reactions to contrast media have a genetic basis (Photo courtesy of Getty Images).
A new study suggests that patients with family and personal history of allergic reactions to iodinated contrast media (ICM) are at risk for future reactions.
Researchers at Chung-Ang University Hospital (Seoul, South Korea), Seoul National University Medical Research Center (South Korea), and other institutions conducted a clinical study to identify the prevalence, patterns, risk factors, and preventive measures for ICM-related hypersensitivity reactions (HSRs). To do so, they recruited 196,081 patients from seven hospitals, who underwent contrast-enhanced computerized tomography (CT) examinations between March 2017 and October 2017. Data were collected on a weekly basis to identify risk factors that predict occurrence and recurrence of HSR.
The results revealed that 0.73% of those that received ICM (1,433 patients) experienced HSRs. Most of the events were mild; however, 16.8% of the events were classified as moderate to severe. Predictors of reaction included a previous individual history of an ICM-related HSR, hyperthyroidism, drug allergy, asthma and other allergic diseases, and a family history of ICM-related HSRs. The researchers also found that use of antihistamines and switching to an iodinated contrast media with a different safety profile were useful for reducing the recurrence of reactions. The study was published on September 3, 2019, in Radiology.
“Hypersensitivity reactions to iodinated contrast media are not rare, but many of them are still preventable. We hope that we can establish a systematic nationwide integrated registry for ICM-related HSRs in Korea soon, and our study could be a first step toward that goal,” said co-lead author Min Jae Cha, MD, of Chung-Ang University Hospital. “Large-scale and long-term registries involving continuous data collection with standardized protocols will help us unravel all aspects of the contributors to the occurrence and recurrence of hypersensitivity reactions to iodinated contrast media.”
Approximately 75 million CT scans are conducted each year in the United States, and half of them include the use of an ICM). In Korea, it is estimated that more than four million CT scans involving ICM usage are performed each year. The link between family history as well as previous individual history of HSRs to ICM suggests a genetic predisposition to a reaction.
Chung-Ang University Hospital
Seoul National University Medical Research Center