This case series describes the use of virtually supported platforms that allowed for remote and virtual delabelling of penicillin allergy using a one step amoxicillin OC. With the limitations of the pandemic, starting in July 2020, patients in the Vancouver and surrounding catchment area who were referred for penicillin allergy were assessed virtually by independent allergists practicing in the community and tertiary health care centres in Vancouver, British Columbia. Given adaptation necessitated by the pandemic restrictions, the option for an amoxicillin OC was offered to all patients and families that were deemed suitable based on (1) the initial review of their reactions, (2) cardiovascular reserve and ability to tolerate anaphylaxis, and (3) urgency of penicillin allergy delabelling. The option for virtual challenge was offered on a case-by-case basis depending on the inflow of relevant referrals from the community. Those individuals who were willing to accept the risk were included in the current communication. There was no pre-specified timeline for this clinical endeavour. The following baseline data was collected: patients’ age, sex, comorbidities, inciting medication, index reaction, risk of reaction, rationale for virtually supervised challenge, and subsequent outcome (Table 1).

The initial consult was conducted on a secure platform which included a video and audio component as this would allow the physician to obtain a baseline appreciation of patient health status within the limitations of virtual visits. During the initial consultation, history was obtained to determine the characteristics of the index reaction, risk of true allergy and risk of adverse reaction to a provocation challenge, according to the Canadian Society of Allergy and Clinical Immunology (CSACI) position statement on beta lactam allergy [3]. The algorithm in the CSACI Position Statement [3] stratifies patients according to risk of future reaction to beta lactam antibiotics and provides guidance on beta-lactam introduction or oral provocation challenge if patients are at low to intermediate risk of reaction. Based on this algorithm, patients that were deemed appropriate for an amoxicillin OC were stratified to the intermediate risk category that still met the criteria to proceed to direct OC, which corresponds to a score of 0–2 (very low to low risk) on the PEN-FAST clinical decision rule. The option to undergo a virtual challenge along with the risks and benefits of the challenge was presented to all patients deemed to be at low to intermediate risk of reaction as per the CSACI beta-lactam allergy risk stratification algorithm [3]. Twenty-three patients accepted the risk and provided verbal informed consent. Features of anaphylaxis, including when to seek medical attention, were discussed. Patients were explicitly told they were able to reconsider at any time including the date of the challenge. All patients who accepted the risk of a virtual challenge between the period of July 2020 to April 2021 are included in the current communication.

Patients who were eligible and consented to proceed with a virtual amoxicillin OC were prescribed amoxicillin for their challenge. Prescriptions for the appropriate dose was called or faxed to their community pharmacy by the attending physician and patients secured the amoxicillin prescription prior to the day of their OC. On the day of the challenge, patients met with their supervising physician on a secure video platform, and a review of their health status was performed to ensure safety. Verbal consent was reviewed, and a single step oral challenge was then carried out, while the physician was on standby via video for 60 min for immediate assistance and guidance in case of a reaction. Patients were required to have a capable friend, family member, or guardian available in their vicinity to function as a caretaker, and counselling provided on when, how, and where to seek immediate medical attention in the event of an adverse reaction requiring immediate care. Given the index history for each patient, a risk of anaphylaxis was felt to be low enough such that no new epinephrine prescriptions were provided for the purpose of the amoxicillin OC alone. Three pediatric patients, ages 3, 12, and 14 had previously diagnosed food allergies and epinephrine auto-injector prescriptions. Caregivers of pediatric patients were in direct contact with the attending physician.

Two virtual visits were required for the virtual challenge to take place, with the initial virtual visit functioning as consultation and assessment of eligibility for the virtual challenge, and the second virtual visit functioning as the visit where the remote OC took place with the algorithm summarized in Fig. 1. Risks, benefits, and consent to proceed with the virtual amoxicillin OC was discussed during both encounters.

(Figure adapted from Mack et al. [8]. JACI: In Practice)

A flow chart and checklist of a virtually supported penicillin oral challenge. A Visit 1: virtual consultation and preparation. B Visit 2: virtually supported home amoxicillin oral provocation challenge. (1) Immediate reaction is defined as Type I hypersensitivity reaction that is IgE mediated and occurs within 2 h of the first dose of medication and lasts < 24 h. (2) Delayed hypersensitivity reaction are defined as Type II–IV reactions that typically take > 24 h to develop and raise concern for end organ involvement (cytopenias, renal/hepatic dysfunction, serum sickness), or severe cutaneous adverse reactions (skin desquamation, purpura, mucosal lesions, SJS/TEN, DRESS, AGEP)

After successful completion of the amoxicillin OC, patients were counselled on the low risk of delayed reactions and when to seek urgent medical care if required. They were provided with instructions to contact the attending physician in the event of any delayed reaction. No formal follow up was scheduled at the end of the OC if patients were otherwise well, with follow up planned on an as needed basis in the event of delayed reactions to the amoxicillin OC or in the context of a course of amoxicillin taken for a subsequent infection.