Chlorhexidine Allergy in 4 Specialist Allergy Centres in the UK, 2009-2013: Clinical Features and Diagnostic Tests

We describe an observational survey of diagnostic pathways in 104 patients attending four specialist allergy clinics in the UK following perioperative hypersensitivity reactions to chlorhexidine reactions. The majority were life threatening. Men undergoing urological or cardiothoracic surgery predominated. Skin prick testing and sIgE testing were the most common tests used for diagnosis. Fifty-three % of diagnoses were made on the basis of a single positive test. Where multiple tests were performed the sensitivity of intradermal, basophil activation and skin prick testing was 68% (50-86%), 50% (10-90%) and 35% (17-55%) respectively. Seven percent were negative on screening tests initially, and 12 cases were only positive for a single test despite multiple testing. Intradermal tests appeared most sensitive in this context. Additional sensitisation to other substances used perioperatively, particularly neuromuscular blocking agents (NMBA), was found in 28 patients, emphasising the need to test for possible allergy to all drugs to which the patient was exposed even where chlorhexidine is positive. This article is protected by copyright. All rights reserved.