Chlorhexidine hypersensitivity

An association between antibiotic resistance and chlorhexidine and QAC resistance in Providencia stuartii and Proteus has been observed, but no evidence of a plasmid link obtained [25, 73, 287,288]. Chlorhexidine hypersensitivity has been noted in ciprofloxacin-resistant variants of Ps. aeruginosa [289] and vancomycin- and gentamicin-resistant strains of E. faecium retained sensitivity to the /usbiguanide [289, 290] and to other biocides [270-272], Anderson et al. [272] studied the inactivation kinetics of VRE and vancomycin-sensitive enterococci (VSE) exposed to environmental disinfectants at concentrations well below (extended dilutions) the recommended use-dilutions and found no differences in susceptibility of VRE and VSE. This type of approach is much more relevant than the widespread usage of MICs to measure responses to biocides. 

Chlorhexidine has found other medical appHcations, eg, in urology in preventing urinary tract infections (217), in obstetrics and gynecology (218), in controlling infection in bums and wounds (219), and in the prevention of oral disease (220). Hypersensitivity to chlorhexidine has been reported in Japan (221) but 0.05% concentration is considered to be safe. 

Iodophors are less irritating and less likely to produce skin hypersensitivity than tincture of iodine. They act as rapidly as chlorhexidine and have a broader spectrum of action, including sporicidal action, but they lack the persistent action of chlorhexidine. 

Beaudouin, E. et al., Immediate hypersensitivity to chlorhexidine literature review, Allerg. Immunol. (Paris) 36, 123-126, 2004. 

Use of preserved tear substitutes with contact lenses is a concern because the preservatives may bind to the lens polymer, prolonging ocular retention and exposure, which may result in toxic or hypersensitivity reactions. BAK is more readily absorbed than are thimerosal and chlorhexidine in most hydrogel lenses. 

Allergic reactions, including anaphylaxis, from chlorhexidine are reported with all types of use and are well documented. However, chlorhexidine may still not be suspected as a possible cause of anaphylaxis when several agents are used in the anesthetized surgical patient, and hypersensitivity to chlorhexidine may not be tested for (37). If a reaction occurs during anesthesia, there is often doubt about the exact agent responsible patch-testing will help if there is doubt about causality. 

Local hypersensitivity reactions to chlorhexidine-impregnated patches occur in neonates (49). In a randomized comparison of povidone-iodine and a chlorhexidine gluconate impregnated dressing for the prevention of central venous catheter infections in neonates, the risk of local contact dermatitis limited the use of the chlorhexidine dressing (50). 

A 64-year-old man had severe anaphylaxis induced by intraurethral chlorhexidine gel 0.05% (53). Previous hypersensitivity reactions during urethral dilatation had been thought to be due to lidocaine. Chlorhexidine-specific IgE antibodies were demonstrated, and the chlorhexidine gel had been used in all the preceding urological procedures the patient had undergone. 

However, although randomized studies have failed to show an association between hypersensitivity reactions and chlorhexidine-impregnated central venous catheters, there have been reports of anaphylaxis after insertion of these catheters (SEDA-22, 262) (56,57), and two life-threatening episodes of anaphylaxis in the same patient were attributed to a central venous catheter that had been impregnated with chlorhexidine and sulfadiazine (58). 

A meta-analysis of the clinical and economic effects of chlorhexidine and silver sulfadiazine antiseptic-impregnated catheters has been undertaken (60). The costs of hypersensitivity reactions were considered as part of the analysis, and the use of catheters impregnated with antiseptics resulted in reduced costs. The analysis used the higher estimated incidence of hypersensitivity reactions occurring in Japan, where the use of chlorhexidine-impregnated catheters is still banned (61). 

Nightingale SL. Hypersensitivity to chlorhexidine-impreg-nated medical devices. JAMA 1998 279 1684. 

Severe anaphylaxis occurred in an 18-year-old woman and a 15-year-old man when polyhexanide was used to clean surgical wounds (2). Immediate-type hypersensitivity to polyhexanide was suggested by positive skin prick tests. Both patients had previously been exposed to chlorhexidine, but skin tests with chlorhexidine were negative. 

Lauerma AI. Simultaneous immediate and delayed hypersensitivity to chlorhexidine digluconate. Contact Dermatitis 2001 44(1) 59. 

Chlorhexidine-impregnated devices Hypersensitivity reactions (SEDA-22, 525)... 

Severe hypersensitivity reactions, including anaphylactic shock, have been reported following the topical administration of chlorhexidine, although such instances are rare given the extensive use of chlorhexidine and it salts. 

Wahlberg JE, Wennersten G. Hypersensitivity and photosensitivity to chlorhexidine. Dermatologica 1971 143 376—379. 

Wahlberg JE (1971) Sensitization to thioxolone. Contact Dermatitis Newslett 10 222 Wahlberg JE (1976) Routine patch testing with irgasan DP 300. Contact Dermatitis 2 292 Wahlberg JE, Wennersten G (1971) Hypersensitivity and photosensitivity to chlorhexidine. Dermatologica 143 376-379... 

Hypersensitivity in cutaneous preparations is often caused by methyl parahydroxybenzoate. Sorbic acid or propylene glycol are to be preferred. Chlorhexidine digluconate, though giving few hypersensitivity, is not used very often because it has quite a few incompatibihties [46]. Propylene glycol is proven safe up to a concentration of 15 % (150 mg/g) but occasionally causes some irritation. Therefore, do not use it in cutaneous preparations that are apphed to non-intact skin. 

Hypersensitivity by eye drops is caused sometimes by thiomersal and benzalkonium chloride, although the adverse reaction to benzalkonium chloride usually regards irritation. Phenylmercuric borate gives fewer hypersensitivity reactions but has been abandoned. Chlorhexidine, as said, is only suitable for a few preparations. 

Instillagel which contains 0.25 % chlorhexidine, 2 % lidocaine, and mixed hydroxybenzoates, demonstrates why its involvement in indncing allergic reactions might in some cases remain unrecognized. A survey in 2005 conclnded that chlorhexidine accounted for 27 % of overlooked perioperative hypersensitivity reactions. 

---