Evidence-based approaches to penicillin allergy de-labelling

Neil Powell combines the roles of consultant antimicrobial pharmacist and clinical researcher at the Royal Cornwall Hospital in Truro. In this series of short videos, he describes the rationale for removal of erroneous penicillin allergy labels and the quest for effective methods.

Why penicillin allergy labels might be a bad thing

Penicillin allergy labelling was intended to prevent accidental administration of penicillins to people who had documented allergies to penicillin, but “less than 5% of those people with an allergy record are genuinely allergic to penicillin so we’re denying penicillin in a lot of people”, explains Mr Powell.  In fact, these people receive alternative antibiotics that are associated with increased risks of side effects, longer hospital stays and treatment failure.

About 70% of those with penicillin allergy labels acquired them in childhood.

What the PALACE study tells us about penicillin allergy de-labelling

Distinguishing who has a genuine penicillin allergy amongst all the people who are labelled as “allergic to penicillin” is an important issue.  Traditionally, this has been achieved by referring all individuals labelled as ‘allergic to penicillin’ to an allergist for blood tests (for specific immunoglobulin E (IgE)) and skin prick testing for penicillins followed by an oral challenge with a penicillin. However, the PALACE study has recently shown that in people at low-risk of penicillin allergy, a direct oral challenge is all that is needed to determine their penicillin allergy status. In this study the PEN-FAST score was used to identify people at low-risk of true penicillin allergy.

Could penicillin allergy de-labelling lead to better outcomes?

It is estimated that up to four million people in the UK could be incorrectly labelled as having an allergy to penicillin. Mr Powell’s research is exploring the implementation of penicillin allergy de-labelling as a standard of care for hospitalised patients. An understanding of the key barriers and enablers in healthcare systems is an essential pre-requisite.  The ALABAMA (ALlergy AntiBiotics And Microbial resistance) study aimed to identify patients from GP records who had low-risk penicillin allergy records, randomise them to ‘allergy-testing’ or ‘not allergy-testing’ (usual care) and then to follow them up to see whether those that had been de-labelled had different health outcomes from those that had not been de-labelled.  The ALABAMA study also investigated patient and GP perspectives of penicillin allergy de-labelling and incorporated a behavioural package to remove some of the barriers.  Part of this was designed to optimise the intervention to ensure that both GPs and patients understood what has been done and that once a patient has been de-labelled, they change their behaviour i.e., prescribe or consume penicillin “and to not continue avoiding it, otherwise the intervention of de-labelling is lost”, says Mr Powell.

The iNAAN (International Network of Antibiotic Allergy Nations) project is a multicentre, observational study of penicillin de-labelling. One of the objectives is to determine the impact of de-labelling, in particular, “to see whether undoing the label undoes the harms”, says Mr Powell.

What does a consultant antimicrobial pharmacist do?

The work of a consultant antimicrobial pharmacist involves not only knowing about antimicrobial medicines but also understanding how people and organisations behave and collaborating with others to optimise antimicrobial prescribing and improve patient care. For example, one important aspect of penicillin allergy de-labelling is ensuring that the incorrect penicillin allergy label does not reappear later, for example, as a result of human error or computer error. This involves working with other health care practitioners and with patients to ensure that all parties understand what has been done and what it means for individuals.

Mr Powell describes his work as a consultant antimicrobial pharmacist as being both demanding and rewarding and he would recommend it to others.

About Neil Powell

Neil Powell is a consultant antimicrobial pharmacist at the Royal Cornwall Hospital. As Associate Director of Antimicrobial Stewardship (for two days a week) he is responsible for ensuring that the hospital is delivering on its antibiotic stewardship program of work. In addition, outside of the hospital he is responsible for ensuring that antibiotic prescribing is appropriate in primary care and the community hospitals. The remaining three days each week are devoted to research – Mr Powell is an NIHR and Health Education England (NIHR/HEE) funded clinical doctoral research fellow.

Read and watch the full series on our website or on YouTube.