Anaphylaxis to anaesthetic drugs.

Severe anaphylactic reactions during anaesthesia increased dramatically in incidence in the mid 1970s. Studies performed in our unit over the subsequent 25 years demonstrated the involvement of IgE in these reactions and the value and safety of intradermal and prick testing in the diagnosis and determination of the drug responsible. Radioimmunoassay studies demonstrated that neuromuscular blocking drugs produce anaphylaxis by cross-linking IgE molecules via their substituted ammonium groups. The IgE binding of these drugs leads to a high incidence of cross sensitivity. Mast cell tryptase measurement is highly sensitive and specific for anaphylaxis although it can be elevated in reactions due to direct histamine release. The reactions are unpredictable from the history. The heart is rarely a target organ in human anaphylaxis although the diseased heart is more likely to fail or produce serious arrhythmias than the normal heart. Colloid solutions produce a better response than crystalloid solutions in the treatment of hypotension. Anaesthetic allergy persists up to 27 years. Subsequent anaesthesia based on the findings of skin testing is usually safe.