First, a systematic allergy risk assessment tool will enable stratification of patients' reported symptoms as (1) low risk (eg, isolated urticarial, maculopapular rash, gastrointestinal symptoms) or (2) high risk (eg, anaphylaxis, severe systemic reactions). Only patients classified low risk will be eligible for oral provocation challenge for allergy delabeling. Patients' ineligible for oral provocation challenge because of history of high-risk allergy symptoms or presence of clinical confounders for oral provocation challenge (eg, uncontrolled asthma) will be referred to the SickKids allergy clinic for further evaluation.

A subset of patients screened with the risk assessment questionnaire will fulfill eligibility criteria to undergo the Oral provocation challenge. Specifically, these will be patients who (1) fulfill several procedural requirements (eg, parent able to observe child for 1 hour after oral provocation challenge), (2) have a previously unevaluated allergy label without high-risk features and without any clinical confounders for the oral provocation challenge, and (3) meet other clinical criteria for oral provocation challenge (eg, vital signs within normal range). These participants will be given a one-time dose of Amoxicillin 17 mg/kg (maximum, 500 mg) and observed for 1 hour for a reaction.

Prospective cohort study of patients presenting to the emergency department with a reported beta-lactam allergy. (1) Allergy history and risk assessment, (2) Oral provocation challenge (if eligible), and (3) Post-discharge follow-up (if received oral provocation challenge or referred to allergy).

In the primary analysis, successful beta-lactam allergy removal will be defined as tolerating oral provocation challenge without any immediate adverse reaction.

This includes questions regarding any prior evaluations, patients' perception of their allergy label, and clinical details of allergy history. The latter involves an allergy history risk assessment, which will screen patient for high-risk features (eg, new maculopapular rash within 2 hours of administering antibiotic). Presence of any high-risk features will disqualify the patient from subsequent study components.

Finally, the questionnaire will screen for presence of any clinical confounders that would preclude administration of the OPC (eg, use of antihistamines within prior 72 hours).