Réaction anaphylactique énigmatique au cabinet dentaire

We report the case of a young boy who was referred to us for suspected anaphylaxis to a local anesthetic during a dental procedure. Shortly after the administration of a local anesthesia using adrenaline-laced articaine, he developed a grade 2 anaphylactic reaction, which was treated with an intramuscular injection of adrenaline. Unable to test articaine (which was still mixed with adrenaline), we tested lidocaine as an alternative and then performed a subcutaneous provocation test, which did not elicit any reaction, allowing us to rule out a lidocaine allergy. However, our skin tests, performed after disinfection with chlorhexidine, were positive for latex, which we initially suspected to be responsible for the anaphylactic reaction. But a control prick-test on untreated skin, not disinfected with chlorhexidine, was negative. Upon further questioning, we discovered that the patient had used a mouthwash containing chlorhexidine immediately before the local anesthesia, which had not initially been mentioned either by the dentist or by the family. The chlorhexidine prick-test, as well as specific IgE testing, both returned positive, ultimately confirming sensitization to chlorhexidine. This was therefore an IgE-mediated allergy to chlorhexidine, likely due to mucosal absorption through the breach caused by the gingival local anesthesia. This case serves as a reminder of the need for a systematic and thorough approach in evaluating drug hypersensitivity. Allergy to chlorhexidine should always be considered when investigating perioperative anaphylaxis, even when the product is well tolerated on intact skin or mucous membranes.