[Clinical examination of challenge test to local anesthetics].

BACKGROUND: Although adverse reactions to local anesthetics are often diagnosed as local anesthetic allergy, there is evidence that most of these reactions occur via non-allergic mechanisms.

METHODS: To evaluate allergic reactions to local anesthetics, challenge tests were performed in 20 patients who had a history of adverse events to local anesthetics for whom dental treatment was planned. The diagnostic protocol of this challenge test consisted of skin prick and intracutaneous tests, as well as subsequent incremental subcutaneous challenge tests with local anesthetics such as lidocaine.

RESULTS: 17 patients (85%) showed no immediate allergic response to lidocaine, which could then be used for dental treatment. Three patients (15%) reacted positively to lidocaine: one had local erythema at the site of the skin prick, and two reacted to subcutaneous challenge.

CONCLUSION: The proportion of immediate-type reactions to local anesthetics is small but not rare in patients suspected of having local anesthetic allergy. This result suggests that the diagnostic approach to confirm allergy to local anesthetics is clinically important and requires further study in a larger population.