Penicillin allergy de-labelling: a strategic approach to combat antimicrobial resistance in the UK
An estimated 2.7 million people in the UK are labelled as “penicillin allergic,” yet about 95% of these labels are found to be incorrect upon testing. This mislabelling leads to the overuse of broad-spectrum antibiotics, contributing significantly to antimicrobial resistance (AMR) and adverse patient outcomes. Senior Pharmacy Technician, Nazira Shaikh gives an overview of the issue and how delabelling can be safely implemented in this clinical feature.
Penicillin has been a cornerstone in treating bacterial infections since its discovery. Common types of penicillin antibiotics include: Phenoxymethyle penicillin, Amoxicillin, and Ampicillin. These antibiotics work by inhibiting the formation of bacterial cell walls, leading to bacterial death. However, an estimated 2.7 million people in the UK are labelled as “penicillin allergic,” yet about 95% of these labels are found to be incorrect upon testing. This mislabelling leads to the overuse of broad-spectrum antibiotics, contributing significantly to antimicrobial resistance (AMR) and adverse patient outcomes. New BSACI guidelines for the de-labelling of penicillin allergy | Anaphylaxis UK.
Understanding penicillin allergy and its implications
Penicillin allergy occurs when the immune system reacts to the drug, ranging from mild rashes to severe anaphylaxis. However, many reported allergies are based on outdated or inaccurate information. This mislabelling often results in patients being prescribed alternative antibiotics, which are broader in spectrum and associated with higher risks of AMR.
Difference between side effects and allergy
Understanding the distinction between side effects and allergic reactions is crucial in clinical practice.
- Side effects: These are unintended, often mild effects that occur when taking a medication. They are dose-dependent and predictable based on the drug’s pharmacological properties. For example, nausea or headache from medication are common side effects.
https://www.verywellhealth.com/what-is-an-adverse-reaction-3959900 - Allergic reactions: These involve the immune system’s response to a substance, leading to symptoms such as hives, swelling, or anaphylaxis. Allergic reactions can occur even with small doses and are not dose dependent. They require immediate medical attention, especially if they involve breathing difficulties or swelling of the face and throat.
Misinterpretation of side effects as allergic reactions can lead to unnecessary avoidance of certain medications, impacting treatment efficacy.
Penicillin allergy and types of reactions
Penicillin allergy occurs when the immune system mistakenly identifies penicillin or its derivatives as harmful, leading to an immune response. This response can range from mild to life-threatening reactions. Allergic reactions to penicillin are typically categorised by how quickly symptoms appear:
The role of de-labelling in antimicrobial stewardship
De-labelling involves reassessing and removing incorrect penicillin allergy labels. Studies have shown that de-labelling can reduce the use of broad-spectrum antibiotics, thereby decreasing the development of resistant bacteria and improving patient outcomes.
Testing for true penicillin allergy
Accurate diagnosis of penicillin allergy is crucial to avoid unnecessary use of broad-spectrum antibiotics and to ensure appropriate treatment. The British Society for Allergy and Clinical Immunology (BSACI) provides guidelines for diagnosing penicillin allergy, emphasising the importance of a thorough clinical history and appropriate testing methods.
1. Clinical history assessment
A detailed clinical history is the first step in evaluating penicillin allergy. This includes reviewing the timing, nature, and severity of previous reactions to penicillin. The BSACI recommends using structured tools like the PEN-FAST score to assess the likelihood of a true allergy.
2. Skin testing
Skin testing is considered the gold standard for diagnosing immediate-type penicillin allergy. It involves applying small amounts of penicillin derivatives to the skin and observing for reactions. The BSACI guidelines suggest performing skin testing in a controlled environment with appropriate emergency equipment available. PubMed
3. Drug challenge
If skin testing results are negative and the clinical history is suggestive of a low risk for allergy, a graded drug challenge may be performed. This involves administering increasing doses of penicillin under medical supervision to confirm tolerance. The BSACI provides detailed protocols for conducting drug challenges safely.
4. Blood tests
Blood tests measuring specific IgE antibodies to penicillin can be used in certain situations, such as when skin testing is not feasible. However, these tests are less commonly used and may not be as reliable as skin testing.
RAST Test: How It Tests for Allergies and Pros and Cons
Accurate diagnosis of penicillin allergy is essential for effective antimicrobial stewardship and patient safety. Healthcare professionals should follow established guidelines and protocols to ensure appropriate testing and management of suspected penicillin allergies.
Implementing de-labelling in the UK healthcare system
The British Society for Allergy and Clinical Immunology (BSACI) has developed guidelines for setting up penicillin allergy de-labelling services by non-allergist clinicians in hospital settings. These guidelines provide a framework for safe and effective de-labelling, including patient selection, risk stratification, and the use of drug provocation tests.
New BSACI guidelines for the de-labelling of penicillin allergy | Anaphylaxis UK
A pilot study in a UK hospital demonstrated the feasibility of a pharmacist-led multidisciplinary penicillin allergy de-labelling service. The study found that 88.9% of low-risk patients could be safely de-labelled, leading to a reduction in the use of alternative antibiotics and associated cost savings.
Removal of incorrect penicillin allergy labels in a UK hospital – PubMed
The crucial role of pharmacists
Pharmacists are integral to the de-labelling process. They can assess patient histories, perform risk stratification, and collaborate with medical teams to implement de-labelling protocols. Their involvement ensures that patients receive appropriate antibiotic therapy, enhancing both safety and efficacy.
Penicillin allergy de-labelling is a critical strategy in the UK’s fight against AMR. By accurately identifying true allergies and removing incorrect labels, healthcare providers can optimise antibiotic use, reduce resistance, and improve patient care. The active participation of pharmacists and adherence to established guidelines are essential for the successful implementation of de-labelling initiatives.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11046535/
Penicillin allergy poster
Individuals with a severe* allergy to penicillin SHOULD NOT receive a penicillin, cephalosporin or another beta-lactam antibiotic. Individuals with a non-severe** penicillin allergy SHOULD NOT receive a penicillin but cephalosporins, carbepenems and other beta-lactams can be used for these patients with caution as the risk of cross sensitivity is low.
NHS Antibiotics and Penicillin Allergy Poster
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