Anaphylactic and anaphylactoid reactions during the perioperative period.

Anaphylactic reactions in the peri-operative period are often serious and potentially life-threatening conditions, involving multiple organ systems in which the clinical manifestations are the consequence of the release of preformed mediators from mast cells and basophils. Anaphylaxis is an immune mediated type I allergic reaction following the massive release of mediators from mast cells and basophils as a response to an allergen. Anaphylactoid reactions are defined as those reactions that produce the same clinical picture with anaphylaxis but are not IgE mediated, occur through a direct nonimmune-mediated release of mediators from mast cells and/or basophils or result from direct complement activation. The occurrence of these reactions during anesthesia, although quite rare, remains a major concern for the anesthesiologists. Thus, the need for systematic screening before surgery and the awareness and expert advice to anaesthesiologists seems to be very critical.