Chlorhexidine allergy in the perioperative setting: a narrative review

Summary Chlorhexidineis an antisepticwith a broad spectrum of activity and a persistent effect on skin. Consequently, it has become an ubiquitous antisepticin healthcare and the community. As use has become widespread, increasing numbers of cases of allergyhave been reported in the literature, including cases of anaphylaxisto chlorhexidinegels used on mucous membranes, chlorhexidine-impregnated devices such as central venous catheters, chlorhexidinepreparations used on wounds and broken skin, and cases after dental procedures. Numerous governmental warnings have been issued over recent decades to warn of the risk of allergyto chlorhexidineon mucosal surfaces or in medical devices. Whilst the number of published cases likely underestimates the true prevalence of reactions, we retrospectively surveyed clinics with experience in investigating perioperative chlorhexidine allergy. Despite differences in investigation practice before the survey took place, 13 clinics responded which together had diagnosed 252 cases of anaphylaxisto chlorhexidine, and cases of delayed allergy. In eight of 13 clinics, chlorhexidinewas within the top four most commonly diagnosed causes of perioperative anaphylaxis. Despite this, the incidence of anaphylaxisto chlorhexidineis low given that patients are very commonly exposed. Sensitisation of healthcare workers can occur, but is uncommon. Before exposing patients to this antiseptic, consideration of the potential risk vs benefit should be undertaken, particularly for higher risk exposures, such as mucosal exposure or i.v. exposure via impregnated lines. Difficulties exist in protecting patients with known allergiesfrom re-exposure to chlorhexidine, which would be improved with uniform labelling and chlorhexidineproduct registers.