Anaphylactic reactions in anaesthetised patients - four cases of chlorhexidine allergy.

Chlorhexidine is widely used all over the world in many different preparations. In Denmark chlorhexidine is the standard skin disinfectant used before surgery or invasive procedures and it is widely used in the general population in mouthwash or for disinfection of minor scratches etc. The potential for developing allergy to chlorhexidine is thus great, especially in surgical patients. We have identified four patients with serious allergic reactions in connection with surgery and general anaesthesia, who on subsequent skin testing tested positive for chlorhexidine. Symptoms appeared 20-40 min into the operation and all four patients required treatment with adrenaline. All four patients had a history of minor symptoms like rashes or faints in connection with previous surgery/invasive procedures. Allergy to chlorhexidine may be more prevalent in surgical patients and cases may have been overlooked due to the nature of reactions and lack of suspicion towards this substance.