D2.233 - Negative predictive value of skin tests with local anaesthetics

   Local anaesthetics (LA) are commonly used during surgical and dental procedures as well as in topical agents for pain management. Adverse effects associated with administration of LAs are frequent (0.5 to 26% of administrations). However true allergic reactions are believed to be rare and account for less than 1% of events reported.

   Suspicion of LAs hypersensitivity raises concerns in patients and doctors in the context of their future use and may lead to unnecessary avoidance or delay of important surgical procedures. Thus, allergologic work-up based on skin tests and provocations, is often performed in order to find a safe LA for the future use.

   The aim of the study was to determine performance of skin tests with local anaesthetics in relation to provocation in patients with history of immediate hypersensitivity reaction after their past use.

   409 patients (332 women and 77 men; aged 18-85 years, mean age: 47 years) with the history of immediate hypersensitivity reaction after LA were included into the study. Step-wise protocol, including skin prick tests, intradermal tests and subcutaneous provocations was implemented with following LAs: lidocaine, bupivacaine, mepivacaine, articaine. The culprit LAs were not tested. Any positive result excluded tested LA from the next steps. Finally, negative predictive value of skin tests in relation to provocation was calculated.

  In skin prick tests we obtained 34 positive results (3.4%), in intradermal tests – 27 (2.8%). No patients were positive in skin tests with all LAs tested. However three of them had dermatographism making it impossible to assess skin tests, two withdrew consent during diagnostic, two had medical contraindications for drug challenge and six - responded to placebo. As a result, 13 participants were not provoked with LAs.

  In 396 participants we performed 419 provocations altogether, ten of which (2.4%) were assessed as positive. However, in all cases second provocation with another LA was negative. As a result, safe LA for the future use were found in all provoked patients. Negative predictive value of skin tests with LAs was 97% (the highest with mepivacaine: 99%, the lowest with lidocaine: 96%).

   In patients with history of immediate hypersensitivity to local anaesthetics skin tests are characterized by high negative predictive value.