[Allergic reactions to local anesthetics].

We studied 35 patients which had been sent by various specialists to the Allergy department of a general hospital because they had an adverse reaction to some type of local anesthetic. The subjects underwent three types of tests: a prick test, an intradermoreaction test and a provocation test using three local anesthetics: procaine 2%, lidocaine 2%, mepivacaine 1% with no vasoconstrictors or parabens in order to rule out the possibility that the reaction was due to these substances rather than the local anaesthetic being tested. The results indicated that both the prick test and the provocation test of the local anesthetics included in the study were negative for all of the patients. One patient who had an adverse reaction to Hostacain was tested with that same anesthetic. The patient tested positive in the intradermoreaction test with a 1/10 solution but was not able to be tested with a solution free of parabens due to lack of availability. The results of our study coincide with the bibliographic research done in that real allergic reactions to local anesthetics are infrequent. The methodology used effectively distinguishes those patients with a risk of real allergic reactions there by indicating to the physician the safest local anesthetic for the patient.