Allergy and anaphylaxis in anaesthesia.

Immediate hypersensitivity reactions to anaesthetic and associated agents used during the perioperative period have been reported with increasing frequency in most developed countries. Most reactions are of immunologic origin (IgE mediated, anaphylaxis) or related to direct stimulation of histamine release (anaphylactoid reactions). The incidence of anaphylaxis is estimated between 1 in 10000 and 1 in 20000 anaesthesia, and any drug administered in the perioperative period can potentially produce life-threatening immune-mediated hypersensitivity reactions. Neuromuscular blocking agents (NMBAs), latex and antibiotics represent the most frequently involved substances. However, anaphylactic reactions cannot be clinically distinguished from non-immune mediated reactions which account for 30% to 40% of hypersensitivity reactions. Therefore, any suspected anaphylactic reaction must be extensively investigated using combined peroperative and postoperative testing to confirm the nature of the reaction, the responsibility of suspected drugs and to provide precise recommendations for future anaesthetic procedures. These investigations include plasma histamine, tryptase and specific IgE concentration determination at the time of the reaction, and skin tests 6 weeks later. In addition, since no specific treatment has been shown to reliably prevent the occurrence of anaphylaxis, allergy assessment must be performed in all high-risk patients. The need for proper epidemiological studies and the relative complexity of allergy investigation should be underscored. They represent an incentive for further development of allergo-anaesthesiology clinical networks to provide expert advice for anaesthetists and allergologists.