title: De-labelling self-reported penicillin allergy within the emergency department through the use of skin tests and oral drug provocation testing.
abstract: OBJECTIVE
  Self-reported penicillin allergy is common among patients attending the ED, but is a poor predictor of true immunoglobulin E-mediated hypersensitivity to penicillin. We hypothesise that with a combination of skin testing and drug provocation testing, selected patients can be safely de-labelled of their allergy.
  
  
  METHODS
  This prospective study enrolled a sample of patients presenting to an urban academic ED between 2011 and 2016 with a self-reported allergy to penicillin. Standardised skin prick and intradermal testing with amoxicillin and both major and minor determinants of penicillin was performed in the department. If negative, testing was followed by a graded oral challenge of amoxicillin over 9 days. The primary end point was the allergy status of participants at the end of the study.
  
  
  RESULTS
  A total of 100 patients (mean age 42; standard deviation 14 years; 54% women) completed the testing. Of these, 81% (95% confidence interval 71.9-88.2) showed no hypersensitivity to penicillin and were labelled non-allergic. The majority (16/19) of allergies were confirmed by skin testing, with three suspected allergies detected by the oral challenge. Women were more likely than men to have a true penicillin allergy, with odds ratio of 4.0 (95% confidence interval 1.23-13.2). There were no serious adverse events.
  
  
  CONCLUSIONS
  Selected patients in the ED who self-report an allergy to penicillin can be safely tested there for penicillin allergy, using skin tests and oral drug provocation testing. This testing allows a significant de-labelling of penicillin allergy, with the majority of these patients able to tolerate penicillin without incident.
authors.affiliation: Department of Emergency Medicine, St Vincent's Hospital, Sydney, New South Wales, Australia.
authors.forename: Joseph
authors.identifier: http://orcid.org/0000-0002-3698-6823
authors.initials: J
authors.lastname: Marwood
authors.affiliation: Department of Emergency Medicine, St Vincent's Hospital, Sydney, New South Wales, Australia.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Aguirrebarrena
authors.affiliation: The Kirby Institute, The University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Kerr
authors.affiliation: Department of Pharmacy, St Vincent's Hospital, Sydney, New South Wales, Australia.
authors.forename: Susan A
authors.initials: SA
authors.lastname: Welch
authors.affiliation: St Vincent's Clinic, Sydney, New South Wales, Australia.
authors.forename: Janet
authors.initials: J
authors.lastname: Rimmer
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000009:adverse effects; D004342:Drug Hypersensitivity / Q000175:diagnosis / Q000523:psychology; D004636:Emergency Service, Hospital / Q000458:organization & administration; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010406:Penicillins / Q000008:administration & dosage / Q000009:adverse effects*; D011446:Prospective Studies; D057566:Self Report; D012882:Skin Tests / Q000379:methods*
chemical_list: D000900:Anti-Bacterial Agents; D010406:Penicillins
keywords: allergy; emergency medicine; hypersensitivity; penicillin; skin test