WAAW Blog: Spurious penicillin allergy labels: Why de-labelling is an important intervention for Antimicrobial stewardship and the fight against Antimicrobial resistance?

Rashmeet Bhogal

Lead Research Pharmacist ‘SPACE’ study

(A multicentre Study to Investigate a Protocol-Driven Multidisciplinary Service Model to Tackle ‘Spurious Penicillin Allergy’ in Secondary Care (SPACE study; NHIR129069)

PhD student.

Senior Editor JAC-AMR.

As an antimicrobial pharmacist, my goal on daily antimicrobial ward rounds is always to rationalise antimicrobial treatment without compromising clinical outcomes. However, every time I encountered a patient with a penicillin allergy label, I was not completely satisfied with the consultation. In my experience, there seems to be a level of acceptance of ‘spurious’ or an ‘inaccurate’ penicillin allergy label by clinical teams and by the patients’ themselves. Prescribing second-line antibiotics in these patients is also widely accepted in the face of increasing antimicrobial resistance (AMR) and prescribing practices that do not align with local and national antimicrobial stewardship (AMS) strategies. Questioning the validity of the label led to more questions than answers without changes to clinical management.

One night, I had a phone call for IV chloramphenicol for a patient with suspected meningitis and a penicillin allergy. The panic to source IV chloramphenicol overruled taking a comprehensive allergy history. This scenario led to an interest in researching the impact of a penicillin allergy label on the management of sepsis. Our team found that in patients with a penicillin allergy label, the timely management of sepsis was compromised and the overall consumption of antibiotics in Defined Daily doses per patient episode was also greater in these patients when compared to patients without a penicillin allergy label. Link to article: The adverse impact of penicillin allergy labels on antimicrobial stewardship in sepsis and associated pharmacoeconomics: An observational cohort study (IMPALAS study) – PubMed (nih.gov).

In the campaign against AMR, there is a global drive to align antimicrobial treatment with the WHO AWaRe list of antibiotics (2021 ‎AWaRe classification‎ (who.int)). This is not achieved in patients with an inaccurate penicillin allergy label. These labels have an adverse impact on AMS, AMR, clinical outcomes, healthcare costs and possibly even the carbon footprint of antibiotics in the UK NHS. There is also an increased risk of healthcare associated infections e.g. Clostridioides difficile and an increased risk of post-operative surgical site infections. It is therefore important to remove (de-label) an inaccurate penicillin allergy label and prevent re-labelling (putting the label back). It is also important to raise awareness amongst patients about the harms caused by inaccurate penicillin allergy labels.

There is an unmet need for Allergy services in the UK, which is a barrier for good AMS and tackling AMR.  So how can we overcome this barrier and make a real difference to patient care? There is evidence to support the role of a non-allergy specialist e.g. Clinical Pharmacists, to de-label patients with a ‘low risk’ (unlikely to be allergic) penicillin allergy label using a ‘direct oral penicillin’ challenge (DPC). DPC’s do not involve skin testing and have been shown to be safe in patients with a ‘low risk’ penicillin allergy label.

So how can non-allergy specialists embed themselves into a penicillin allergy de-labelling service? The BSACI guideline: BSACI guideline for the set‐up of penicillin allergy de‐labelling services by non‐allergists working in a hospital setting – Savic – 2022 – Clinical & Experimental Allergy – Wiley Online Library, is a great starting point for these discussions with key stakeholders, when setting up such a service. Do we have a validated de-labelling toolkit or protocol for this service? There are many examples of toolkits for risk stratifying a penicillin allergy label and DPC protocols. However, DPC protocols are not yet standardised. So how can we find a model that fits into the UK NHS framework?

The ‘SPACE study’ is a multicentre study including: University Hospitals of Birmingham NHS Foundation Trust, Oxford University Hospitals NHS Foundation Trust and Leeds teaching hospitals NHS Trust. This study is investigating a risk stratification toolkit and a DPC protocol to de-label ‘low risk’ penicillin allergy labels, by non-allergy specialists, in the UK. The aim of the study is to find out what patients, healthcare workers and managers think about a DPC to remove inaccurate penicillin allergy labels in ‘low risk’ patients, to design a safe way to start using DPC in hospitals and estimate costs.

So far, my experience in the ‘SPACE study’ has taught me that patients with a penicillin allergy label aren’t aware of the harm caused by an inaccurate penicillin allergy label. I have also encountered some hesitance from healthcare professionals when de-labelling patients and recognise the need for better education to achieve a holistic view on the benefits of de-labelling an inaccurate penicillin allergy label. The ‘SPACE study’ will be investigating this further and we hope to provide some insight into this.

As a non-allergy specialist, I think it is important to be able to take a comprehensive drug allergy history. Education on how to take a comprehensive drug allergy history is a key milestone for achieving success with de-labelling inaccurate penicillin allergy labels. I have put together an infographic (figure 1) for investigating a penicillin allergy label.

I have learnt that there are limitations for non-allergy specialists, and therefore it is important that a penicillin allergy de-labelling service is set-up with oversight from a specialist immunologist/allergist.

In future, I hope to see spurious penicillin allergy de-labelling as part of local and national AMS strategies. I encourage efforts across the primary and secondary care interface to prevent re-labelling with inaccurate allergy labels after this has been removed.

Figure 1: Infographic for investigating a penicillin allergy label.

This infographic has been reviewed by: Sarah Denman (Highly Advanced Clinical Pharmacist), Kornelija Kildonaviciute (Research Pharmacist SPACE study) and Bee Yean Ng (Research Pharmacist SPACE study).