Adverse reaction to dental local anaesthetic injection--'allergy' is not the cause.

Objective: To investigate patients considered to have experienced allergic reactions to local anaesthetics administered for dental treatment.

Setting: Dental facility within a general hospital.

Procedure: Skin and intra-oral challenge tests.

Results: No patients were found to be allergic to lignocaine or prilocaine. The most likely causes of the adverse reactions were found to be psychogenic.

Conclusion: Although allergy to lignocaine (and the other amide anaesthetic agents used in dentistry) is known to be extremely rare, it continues to be suggested as a cause when adverse reactions to dental injections occur. Psychogenic reactions are the main causes of untoward events, and some can be alarming. A smaller proportion of adverse responses can be attributed to (avoidable) intravascular injections. Adverse reactions can be reduced if injections are administered carefully.