Administration of local anesthetics to patients with a history of prior adverse reaction.

The clinical histories of 71 patients evaluated for suspected local anesthetic (LA) allergy were reviewed retrospectively. The clinical histories were classified into (1) immediate generalized reactions (15%), (2) localized swelling at the injection site (25%), (3) nonspecific systemic symptoms (42%), and (4) other histories (17%). Serial dilutional intradermal skin tests were performed with mepivacaine, lidocaine, and procaine in 59 patients. There were 5 skin test--positive patients found, and each had a positive reaction to an LA to which, by history, they had not reacted. In 50 patients, when an LA was subsequently required, a subcutaneous challenge was performed with an LA chosen for chemical nonsimilarity. No significant reactions were observed in this group. Three patients tolerated a challenge with an LA to which they were skin test--positive. These data indicate (1) the low incidence of reactions compatible with a systemic IgE-mediated mechanism by history in patients referred for evaluation of LA allergy, (2) the lack of specific and clinically relevant information provided by dilutional skin tests, and (3) the apparent safety and usefulness of careful challenge with an alternative LA.