Benzocaine anaphylaxis

In a 10-year retrospective study of 5464 patients subjected to patch testing with mixes of numerous caine drugs, benzocaine accounted for 22 out of 91 patients whose reactions were deemed allergic, and therefore 22 of 5464 (0.4%) patients had positive type IV reactions to benzocaine.5 No patients reported symptoms consistent with immediate hypersensitivity (type I). Positive skin test reactions to amide anesthetics (articaine, lidocaine) have been reported in 2 cases, but these patients received the injectable form and only had mild reactions (cutaneous without loss of consciousness).7,8 There have also been reports of anaphylaxis to lidocaine9 and lignocaine,10 but these agents were given intravenously.