ffecting about 10% of patients, penicillin drug allergy is the most frequently reported drug allergy. 1 Penicillin drug allergy is commonly diagnosed after a childhood rash is assumed to be caused by recent penicillin administration but which is not investigated further. 2 T-lymphocyte-mediated nonimmediate reactions typically present with maculopapular rashes days after ingestion. 3 In contrast, immunoglobulin E (IgE)-mediated immediate reactions occur within the first hour and appear as urticaria, angioedema, rhinitis, bronchospasm or, rarely, as anaphylaxis. 2,4 Despite their clinical use for over 70 years, penicillin and penicillin-related antibiotics continue to be recommended for first-line therapy in numerous respiratory tract, skin, joint and cardiovascular infections. 5,6 Although most reactions following use of penicillin and related antibiotics are not true drug allergies, medical practitioners often prescribe less effective or more expensive alternatives. [7][8][9] This leads to an increased risk of adverse events, more drug-resistant organisms and more Clostridium difficile infections. 10,11 Presently, primary care providers struggle to rule out penicillin drug allergies. 12 A referral to an allergist for all patients with suspected penicillin drug allergy is impractical, as there are millions of patients with presumed penicillin allergy. 13 In Canada, there is less than 1 allergist per 100 000 people. Not surprisingly, this translates to long wait times, with an estimated wait time for penicillin drug allergy consultation of 12-18 months in rural southwestern Ontario (H. K., unpublished observations, 2019).Primary care providers have limited experience and training in performing skin testing for drug allergy or measurement of specific IgE levels. Skin testing can be inconvenient and time Amoxicillin oral provocation challenge in a primary care clinic: a descriptive analysis