Are we numb to the facts? Our experience of local anaesthetic allergy testing in a tertiary hospital immunology department

Abstract

Introduction Anaphylaxis, although rare, can occur in dental settings. While local anaesthetics (LAs) are widely used in dentistry, true allergic reactions to LAs are uncommon. Most adverse reactions associated with their use are non-allergic in nature, often resulting from factors such as vasovagal syncope, toxicity, or procedural trauma. The overlap in clinical presentation makes distinguishing true allergic reactions from other causes particularly challenging.Aims To determine the prevalence of true LA allergies and characterise the nature of adverse drug reactions (ADRs) following LA administration.Design Retrospective, observational study.Materials and methods Data from 37 patients referred with suspected LA allergies (December 2021 to June 2024) were analysed. Skin prick testing, intradermal testing, and drug provocation tests were performed to assess ADRs and identify potential allergens, including co-administered medications.Results None of the patients tested positive for immunoglobulin E (IgE)-mediated LA allergies. Four patients had allergies to co-administered agents, while other reactions were non-allergic, including vasovagal syncope and procedural trauma.Discussion True IgE-mediated LA allergies are rare. Non-allergic reactions, such as vasovagal syncope and toxicity, are more common and often misinterpreted as allergies.Conclusion Accurate diagnosis is essential to distinguish between true allergies and non-allergic reactions, especially in dental settings. Enhanced training can help reduce misdiagnosis and unnecessary interventions.