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This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.

Millions of people in the UK have penicillin allergy recorded in their medical notes. Many of them are not truly allergic. New research highlights the importance of both doctors and patients discussing recorded penicillin allergies.

Penicillins are first-line treatment for many infections. People with a penicillin allergy listed in their medical records will not receive them. This keeps people with a true allergy safe. However, it means that people who are not allergic will receive second choice antibiotics if their notes are incorrect. This can mean longer hospital stays and more risk of antibiotic-resistant bacteria.

This research explored patients’ and physicians’ views on penicillin allergy. It found that both groups were often unsure if the allergy was true. There was also confusion over the difference between a side effect and an allergy. Patients tended not to question the allergy once it was in their notes. Similarly, doctors were often reluctant to override the allergy record in case of an allergic reaction.

Having penicillin allergy wrongly included in medical notes has negative consequences. The study is part of a larger project designed to see if testing for penicillin allergy and removing incorrect records improves patient health outcomes and antibiotic use.

Currently, few GPs have access to testing for penicillin allergy or know how to refer people. These results show the need for more widespread communication about testing. More testing would mean that many people could safely have penicillin allergy removed from their records.

Further information on penicillin allergy is available on the NHS website.

What’s the issue?

Antibiotics, particularly penicillins, are used to treat bacterial infections. Around 1 in 15 people have an allergy to antibiotics listed in their medical records. Three million people in the UK are unable to access highly effective penicillins.

Most reported reactions to penicillins are mild. However, true allergic reactions can be severe, and include breathing difficulties and loss of consciousness.

Previous research has suggested that as few as 1 in 10 people with a penicillin allergy listed in their medical records are truly allergic. Occasionally, symptoms of the infection being treated (such as a rash) can be confused with an allergic reaction. Or side effects might be thought to be an allergy. The most common side effects of antibiotics affect the digestive system (vomiting, nausea, diarrhoea). They are usually mild and stop when treatment finishes. Symptoms or side effects can lead to an allergy being incorrectly listed in medical records.

Penicillin is an effective first-choice antibiotic. People with penicillin allergy listed in their records are given the next best medication. Allergies are included in medical records to safeguard people against having a reaction. However, having a penicillin allergy listed in medical records is linked with negative outcomes. They include longer hospital stays, more antibiotic prescriptions, an increased risk both of surgical-site infection and infection with antibiotic-resistant superbugs, and death. It is therefore important to ensure the information is accurate.

The National Institute for Health and Clinical Excellence (NICE) asks clinicians to ‘double check’ patients with a penicillin allergy recorded. This is because another antibiotic might not be as effective for their illness. In addition, many alternatives to penicillin (broad-spectrum antibiotics) act against a wider range of bacteria. They are more likely to promote antibiotic resistance. Progress towards new antibiotics has been slow.

This study explored clinicians’ and patients’ views of penicillin allergy, and of testing for it.

What’s new?

Researchers interviewed 31 patients with documented penicillin allergy in the North of England. They also interviewed 19 primary care physicians both with and without experience of dealing with penicillin allergy.

Five main themes emerged from the interviews.

1. Patients’ understanding of allergy

Many people were diagnosed with allergy a long time ago. They were more convinced of their allergy if symptoms occurred immediately after taking penicillin, or were very severe. Some questioned if allergy was hereditary. Many were unclear about the difference between side effects and allergies.

2. Impact of allergy on patients

People who believed themselves to have a true allergy typically reminded healthcare professionals of their allergy and checked medicines for penicillin. People who were at risk of recurrent infections worried more about running out of antibiotic options than those who rarely took antibiotics.

3. Doctor-patient interaction

Most patients accepted the diagnosis of allergy without question and did not discuss it with their physician. Some would take advice from their physician about whether allergy testing would be beneficial.

4. Doctors’ uncertainties about diagnoses

Doctors said they routinely checked medical records for allergies, and valued reminders on the electronic system. Some also checked with the patient. Others noted that the on-screen system did not distinguish between side effects and allergies. This made several doctors doubt allergy status. Physicians also queried how the diagnosis was originally made and whether it was based on family history.

Most doctors were aware of the over-diagnosis of penicillin allergy. A severe reaction (anaphylaxis) was clear-cut but some symptoms (such as rash) made allergy difficult to diagnose.

5. Prescribing decisions

Doctors did not find it difficult to source alternative antibiotics when there was only one allergy. Even when they doubted the recorded allergy, they often avoided prescribing penicillin. Some doctors challenged the recorded allergy, for instance where penicillin was the best choice. They discussed it with the patient and came to a decision together after reviewing the medical history.

Some doctors had referred patients for allergy tests, though most were uncertain about the criteria needed and what testing involved. Doctors rarely initiated discussions about the negative consequences of having a penicillin allergy recorded in medical notes. They said this was because it would not affect the patients’ day-to-day lives.

The research team concluded that both doctors and patients should be more aware of the negative consequences of having penicillin allergy incorrectly included in medical notes.

Why is this important?

Diagnosing penicillin allergy is clinically difficult and medical records are often incomplete. Doctors tend not to prescribe penicillin if an allergy is noted, even when they doubt it is a true allergy.

The interviews identified gaps in patients’ understanding of penicillin allergy and how it differs from side effects. More discussions between doctors and patients would be helpful.

The research concluded that doctors as well as patients need to be convinced of the negative consequences of keeping an inaccurate diagnosis in records. Some felt it was an issue in the hospital setting, rather than in primary care. Highlighting the negative impacts could lead to more open discussions between patients and their GPs.

The benefits of testing for penicillin allergy also need to be stressed, the study found. Doctors need more information about how to arrange testing for patients.

What’s next?

Both doctors and patients need to understand the potential harms associated with having penicillin allergy wrongly noted in medical records. Healthcare professionals could be encouraged to supply more detail in medical records about the initial reaction to penicillin. They also need support to de-label low-risk patients in primary care. Decision aids and algorithms might help to establish whether a medication has caused harm, and whether testing is needed.

The current study was part of a larger project called ALABAMA (Allergy Antibiotics and Microbial Resistance), led by the University of Leeds. Other research by the same team is aiming to find clinically- and cost-effective ways of correcting a false record about penicillin allergy. As part of this work, the researchers are looking to make allergy testing more efficient. It currently requires two visits. The team are exploring ways of testing for allergy in a single visit.

You may be interested to read

This NIHR Alert is based on: Wanat M, and others. Management of penicillin allergy in primary care: a qualitative study with patients and primary care physicians. BMC Family Practice 2021;22:112

Another paper from the same team: Wanat M, and others. Patient and primary care physician perceptions of penicillin allergy testing and subsequent use of penicillin-containing antibiotics: a qualitative study. The Journal of Allergy and Clinical Immunology: In Practice 2019;7:1888-1893


Funding: This work was funded by the NIHR under its Programme Grants for Applied Research Programme.

Conflicts of Interest: The study authors declare no conflicts of interest.

Disclaimer: NIHR Alerts are not a substitute for professional medical advice. They provide information about research which is funded or supported by the NIHR. Please note that views expressed in NIHR Alerts are those of the author(s) and reviewer(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.

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