Objective: To identify the true nature of an acute reaction in 25 patients initially diagnosed as allergic to local anaesthetic drugs.
Setting: University General and Dental Hospitals.
Interventions: Detailed review of each patient's previous exposure to local anaesthetic drugs and of the history of the acute event was followed up with challenge testing by intradermal injection.
Results: One patient was subsequently found to be genuinely allergic to a local anaesthetic drug of the amide type. A wide range of conditions had actually precipitated the other adverse reactions, but all could be classified under three major headings: an immunological condition to a different antigen; a manifestation of anxiety; or an iatrogenic problem.
Conclusion: Local anaesthetic allergy is rare, but does occur. All reactions to local anaesthetic drugs must be assessed carefully and specialist referral may be appropriate.