Summary
Indroduction. More than 100,000 computed tomography scans are performed in Lithuania every year, and about half of them – with iodinated contrast media, which enhance the visibility of organs and blood vessels. Although iodinated contrast media is considered safe, about 0.7–3% of patients experience immediate and 2–5% of patients experience non-immediate hyper sensitivity reactions after the injection.
Clinical case. A 62-year-old woman experienced a non-immediate hyper sensitivity reaction to the iodine contrast agent. Skin tests were negative, but the diagnosis was confirmed with an intravenous drug provocative test and a skin biopsy. The safe iodinate contrast agent was defined after allergological work-up.
Discussion. Prick and intradermal tests are used for diagnostic of immediate reactions, intradermal and patch tests – for non-immediate. Although potentially dangerous to a patient and not yet validated for every day clinical use, an intravenous drug provocation test is considered to be a gold standard, especially in diagnostics of non-immediate type reactions. Laboratory tests (histamine, tryptase, drug-specific IgE antibodies concentration in serum, basophile activation and lymphocyte transformation tests) are safe, but their diagnostic value is not yet clear.
Conclusion. Diagnostics of non-immediate hypersensitivity reactions to iodinated contrast media remain challenging, as standard skin tests are not accurate enough. Although intravenous provocative test and laboratory tests are promising for diagnosis confirmation, further research is needed to validate them for daily clinical use.
