Allergy to local anesthetics: comparison of patch test with prick and intradermal test results

The interrelation between immediate and delayed hypersensitivity reactions to local anesthetics is poorly understood. Especially, the relevance of positive patch test reactions to local anesthetics with regard to the compatibility of injected local anesthetics is unclear. We therefore subjected 104 patch test-positive probands to prick and intradermal tests with seven local anesthetic agents. All prick tests were negative. Only 14 patients showed positive reactions in intradermal tests: 11 with the ester local anesthetic procaine, one with the amide local anesthetic butanilicaine, and two with both. Procaine yielded both immediate and delayed reactions; butanilicaine, only immediate reactions. All other local anesthetics showed negative reactions. It is concluded that in patients with positive patch test reactions to local anesthetics and negative history of anaphylactoid reactions, positive skin test reactions to intradermal application are rare and that, therefore, the risk of anaphylactic reactions to injection anesthesia with amide local anesthetics, except butanilicaine, appears low in these patients.