Skin testing - useful or not for diagnosis of contrast medium allergy?

Skin testing in hypersensitivity reactions to iodinated contrast media

Iodinated contrast media cause both immediate and nonimmediate hypersensitivity reactions.

The study included skin prick, intradermal and patch tests with a series of contrast media in 220 patients with either immediate or nonimmediate reaction.

Seventy-one never-exposed subjects and 11 subjects who had tolerated contrast medium exposure, served as negative controls.

Skin test specificity was 96-100%. Evidence on allergy testing is best for iodinated RCM, limited for blue dyes, and insufficient for fluorescein http://buff.ly/1kV8ujV

50% of immediate reactors and 47% of nonimmediate reactors were skin test positive.

For immediate reactors, the intradermal tests were the most sensitive, whereas delayed intradermal tests in combination with patch tests were needed for optimal sensitivity in nonimmediate reactors.

The authors concluded that at least 50% of hypersensitivity reactions to contrast media are caused by an immunological mechanism.

Skin testing appears to be a useful tool for diagnosis of contrast medium allergy.

References:

Skin testing in patients with hypersensitivity reactions to iodinated contrast media - a European multicenter study. Brockow K, Romano A, Aberer W, Bircher AJ, Barbaud A, Bonadonna P, Faria E, Kanny G, Lerch M, Pichler WJ, Ring J, Rodrigues Cernadas J, Tomaz E, Demoly P, Christiansen C; European Network of Drug Allergy and the EAACI interest group on drug hypersensitivity. Allergy. 2009 Feb;64(2):234-41.

Pearls and Pitfalls of Allergen Testing - JCAAI http://goo.gl/6ThcC and http://goo.gl/Bfnhn
3% of patients who are exposed to iodinated contrast media develop delayed hypersensitivity reactions. Skin prick test is negative but the patch test is positive. Medscape and JACI, 2011.
Image source: Wikipedia, GNU Free Documentation License and public domain.

Radiocontrast media skin tests for screening is of no clinical utility in predicting hypersensitivity reactions http://buff.ly/16vgUsF
Skin Testing for Suspected Iodinated Contrast Media Hypersensitivity http://bit.ly/2n67Euf

Twitter comments:

@AllergyNet: Do you feel a reasonable clinical approach is to give all reactors the same advice and forgo skin testing?

@Alergy: Yes. Pre-procedure protocols generally work well. We do not do routine testing at this time: http://goo.gl/uPVvY