Local anesthetics allergy: who should be tested?

Objective. To document the test results of patients referred to our clinic for testing with local anesthetics (LAs) in real life conditions and provide data related to the necessity of these tests. Methods. All consecutive subjects who were referred to be evaluated for LA allergy during a two-year follow up were included in the analysis. All subjects underwent skin prick / intradermal tests followed by a subcutaneous provocation test with the LAs tested. Results. A total of 228 subjects were included. The main referral reason was the presence of a history of drug hypersensitivity reaction (DHR) to drugs other than LAs (n = 128; 56%), whereas a history of LA allergy constituted the second most common referral reason (n = 64, 28.1%). In the majority of cases (n = 39; 60.9%), the culprit LA was not known by the patients. Asthma was the third most common referral reason, presented in 49 cases (21.5%). Ten cases had positivity to the tested LA in skin testing / challenges. Nine out of 10 patients had a history of DHR to drugs other than LA, whereas 5 of them had also a history of DHR to LA. Six of the 10 patients had a history of multiple DHR. None of the asthma patients without any DHR history were positive in the LA tests. Eight out of 10 cases who underwent skin testing / challenge with an alternative LA, tolerated the alternative LA. Conclusion. The most common referral reason for testing with LA was a history of DHR to drugs other than LAs, whereas asthma was the third most common referral reason. Patients with a history of multiple DHR may be considered for testing with LAs. Asthmatics and those with other allergic diseases without a history of drug / LA allergy do not need to be tested with LA.