Chlorhexidine is a widely used antiseptic and disinfectant. An increasing number of immediate, IgE-mediated, reactions to this drug have been reported. We present two cases of very severe reactions after its topical use.
Methods:
Two patients, aged 3 and 77, who suffered anaphylactic shock after contact with topical chlorhexidine were studied. The first case was a 3-year-old boy who underwent hypospadias surgery; among other drugs, chlorhexidine was used. He developed sudden hypotension, desaturation and facial swelling. The boy did not respond to adrenalin and efedrine; inotropic support at the Paediatric Intensive Care Unit was required. The second case was a 77-year-old woman who had a wound that was sutured at the Emergency Room (ER). She presented cough, dysphonia, palmar itching, universal erythema and hypotension that was refractary to intramuscular adrenalin. Mepivacaine was used as local anaesthetic and clorhexidine as disinfectant. In both cases, tryptase and specific IgE to clorhexidine and latex were measured (ImmunoCAP FEIA, Thermo Fisher Scientific), skin tests to clorhexidine (0.5% chlorhexidine digluconate in 0.9% saline) and the other implicated drugs were performed, and also challenge tests were done when needed.
Results:
Case 1. Tryptase during reaction: 13 μg/L; basal tryptase < 1 μg/L. Prick test to clorhexidine: 8x12mm. Negative prick test to latex, negative prick and intradermal tests to rocuronium, fentanyl and bupivacaine were obtained. IgE to clorhexidine: 2.31 kU/L. Subcutaneous challenge test to bupivacaine: negative.
Case 2. Tryptase during reaction: 19 μg/L; basal tryptase 6.8 μg/L. Prick test to clorhexidine:11x12 mm. Negative prick test to latex, negative prick and intradermal tests to mepivacaine were obtained. IgE to clorhexidine:3.64 kU/L. Subcutaneous challenge test to mepivacaine: negative.
Conclusion:
Allergic reactions to chlorhexidine are not common if we consider its widespread use in healthcare settings. However, these reactions can be life-threatening even after topical use so awareness is needed, especially at the ER and at perioperative environments. IgE determination and skin tests are useful tools to get an accurate diagnosis of these patients. Chlorhexidine can be used as an excipient of several medications and cosmetics, therefore a thorough information must be given to chlorhexidine allergic patients in order to avoid further contact with this agent.