Risk of Immediate-Type Allergy to Local Anesthetics is Overestimated—Results from 5 Years of Provocation Testing in a Danish Allergy Clinic

Background Local anesthetics (LAs) are used in many health care settings and exposure during a lifetime is almost inevitable. Immediate-type allergy to LAs is considered rare among allergy experts but is commonly suspected by health care workers from other specialties, and by patients. Objective The main aim of this study was to investigate the incidence of immediate-type allergy to LAs in our regional allergy clinic over the 5-year period 2010 to 2014. Methods This was a retrospective single-center study of patients referred to a regional allergy clinic (excluding patients with perioperative reactions) with suspected immediate allergy to LAs, who had undergone subcutaneous provocation with 1 or more LAs. Patients were identified in the hospital clinical coding system and clinical information about the reaction and investigation results was obtained from their medical records. Results A total of 164 patients (123 women/41 men; median age, 56 years; range, 7-89 years) who had 189 provocations with LAs were included over the 5-year period 2010 to 2014. All 164 patients had negative subcutaneous provocations to all 189 tests with LAs (95% CI, 0%-1.83%). Another allergen was identified in 10% (n = 17) of the patients. Conclusions None of the 164 patients with suspected immediate-type allergy to LAs reacted on provocation. Thus, no patients have been diagnosed with an immediate allergy to LAs in our regional allergy clinic in the 5-year period studied, and allergy to LAs must be considered very rare. Alternative mechanisms should be considered, but if symptoms are consistent with allergy, other potential allergens should be investigated.