Sustaining and spreading penicillin allergy delabelling: A narrative review of the challenges for service delivery and patient safety

Characteristics, risk factors and clinical impact of penicillin and other antibiotic allergies in adults in the UK General Practice: A population-based cohort study

OBJECTIVE

To assess the characteristics, risk factors and clinical impact of penicillin and other antibiotic allergy labels in general practice in the UK.

DESIGN

Population-based cohort study.

SETTING

Primary care in the UK, 2000-2018.

PARTICIPANTS

Adults aged 18-100 years who were registered with their general practice for at least 12 months between 01-Jan-2000 and 31-Dec-2018 and followed until 25-Sep-2019.

MAIN OUTCOME MEASURES

The main outcomes include the annual prevalence and incidence of penicillin and other antibiotic allergy labels. Multinominal logistic regression was used to examine the characteristics associated with receiving an allergy label to different antibiotics. Cox regression modelling was used to compare the risk of resistant infections (methicillin-resistant Staphylococcus aureus [MRSA] and vancomycin-resistant enterococci) as well as Clostridioides difficile (C.difficile) infection between patients with and without allergy labels. The monthly proportion of patients who had a penicillin allergy test, either before their allergy label was recorded or within one year, was calculated to assess any impact of NICE penicillin allergy assessment recommendations (Clinical guideline [CG183]) in September 2014.

RESULTS

Both the prevalence and incidence of penicillin allergy label showed a pattern of initial growth followed by a decline. The prevalence reached a maximum of 8.25% in 2011, and the incidence peaked at 0.46% in 2004. Older age, being female, living in less deprived areas, belonging to a larger general practice, and having co-morbidities were associated with a higher chance of receiving a penicillin or other antibiotic allergy label. Patients with antibiotic allergy labels were more likely to receive alternative broad-spectrum antibiotics and had a higher risk of MRSA and C.difficile infections. The introduction of NICE drug allergy guideline did not alter the proportion of patients undergoing penicillin allergy assessment.

CONCLUSION

Penicillin and other antibiotic allergy labels are common and lead to radical change in the antibiotic prescribing practices and are associated with resistant and healthcare associated infections.

Antepartum vs postpartum amoxicillin oral challenge in pregnant patients with a reported penicillin allergy: A two-center prospective cohort study

INTRODUCTION

While 10% of pregnant individuals report a penicillin allergy, there is no established best practice for penicillin allergy delabeling in pregnancy. To better understand options for penicillin delabeling, we aimed to evaluate two penicillin allergy delabeling protocols in pregnancy regarding efficacy, adverse events, and patient satisfaction.

MATERIAL AND METHODS

From July 2019 to December 2022, we completed a two-center prospective cohort study, where each site recruited pregnant patients over 24 weeks gestational age with a reported penicillin allergy. One center offered antepartum amoxicillin oral challenges, either directly or after negative skin testing (i.e., antepartum oral challenge site). Our other centers completed a two-step approach with antepartum penicillin skin testing only and deferred oral challenges to the postpartum period (i.e., postpartum oral challenge site). Our primary outcome was the rate of penicillin allergy delabeling, defined as tolerating an antibiotic challenge with penicillin or amoxicillin. Univariate analyses were completed using chi-squared, Fisher's exact, and Wilcoxon rank tests.

RESULTS

During the study period, 276 pregnant patients were assessed, with 207 in the antepartum oral challenge site and 69 in the postpartum oral challenge site. Among the 204 patients who completed antepartum oral challenges, 201 (98%) passed without reactions. Deferring oral challenges to the postpartum period led to a loss of follow-up for 37/53 (70%) of eligible individuals. Overall, 97% (201/207) of patients at the antepartum oral challenge site were delabeled from their penicillin allergy-compared to 38% (26/69) of patients referred to the postpartum oral challenge site (p < 0.0001). Three antepartum oral challenge reactions were noted, including two mild cutaneous reactions and a case of transient abdominal discomfort.

CONCLUSIONS

Antepartum amoxicillin oral challenge is a more effective method to delabel pregnant patients from their penicillin allergy. Deferral of oral challenges to the postpartum period introduces a significant barrier for penicillin allergy delabeling.

Factors influencing implementation and adoption of direct oral penicillin challenge for allergy delabelling: a qualitative evaluation

BACKGROUND

Over 95% of penicillin allergy labels are inaccurate and may be addressed in low-risk patients using direct oral penicillin challenge (DPC). This study explored the behaviour, attitudes and acceptability of patients, healthcare professionals (HCPs) and managers of using DPC in low-risk patients.

METHODS

Mixed-method, investigation involving patient interviews and staff focus groups at three NHS acute hospitals. Transcripts were coded using inductive and deductive thematic analysis informed by the Theoretical Domains Framework.

FINDINGS

Analysis of 43 patient interviews and three focus groups (28 HCPs: clinicians and managers) highlighted themes of 'knowledge', 'beliefs about capabilities and consequences', 'environmental context', 'resources', 'social influences', 'professional role and identity', 'behavioural regulation and reinforcement' and a cross-cutting theme of digital systems. Overall, study participants supported the DPC intervention. Patients expressed reassurance about being in a monitored, hospital setting. HCPs acknowledged the need for robust governance structures for ensuring clarity of roles and responsibilities and confidence.

CONCLUSION

There were high levels of acceptability among patients and HCPs. HCPs recognised the importance of DPC. Complexities of penicillin allergy (de)labelling were highlighted, and issues of knowledge, risk, governance and workforce were identified as key determinants. These should be considered in future planning and adoption strategies for DPC.

Barriers to and Facilitators of Delabelling of Antimicrobial Allergies: A Qualitative Meta-synthesis

Background

Patients who report penicillin allergies may receive alternative antibiotics. Such substitution contributes to antimicrobial resistance, lower treatment efficacy, increased frequency of adverse events, and increased costs. Approximately 90% of individuals who report a penicillin allergy can tolerate a penicillin.

Objective

To identify the barriers to and facilitators of removal by health care workers of inaccurate antimicrobial allergies from patient records, known as delabelling.

Data Sources

The MEDLINE database was searched from inception to December 29, 2020.

Study Selection and Data Extraction

Qualitative studies evaluating health care professionals' perceptions of barriers to and/or facilitators of the act of delabelling a patient's antimicrobial allergies were included in the meta-synthesis.

Data Synthesis

The Theoretical Domains Framework was used to code and group individual utterances from the included studies, which were mapped to the Behaviour Change Wheel and corresponding intervention function and policy categories.

Results

Four studies met the inclusion criteria. Eight themes were identified as representing barriers to delabelling: delabelling skills, patient education skills, knowledge, electronic health records (EHRs), communication frameworks, time, fear about allergic reactions, and professional roles. Behaviour change interventions that may overcome these barriers include education, training, algorithms and toolkits, changes to EHRs, use of dedicated personnel, policies, incentivization of correct labelling, and an audit system.

Conclusions

Eight themes were identified as barriers to delabelling of antimicrobial allergies. Future behaviour change interventions to address these barriers were proposed. Confidence in the findings of this study was judged to be moderate, according to the GRADE CERQual approach.

Safety Aspects and Rational Use of Single Intramuscular Dose Ceftriaxone: Clinical Insights on the Management of Uncomplicated Gonococcal Infections

Gonorrhea, a sexually transmitted infection caused by Neisseria gonorrhoeae, is a grave public health concern. Gonorrhea is the second most reported sexually transmitted infection worldwide. The treatment of uncomplicated gonococcal infections has evolved dramatically in response to the emergence of antimicrobial resistance. Multiple resistance mechanisms (for example, beta-lactamase production, antimicrobial efflux, and target site modification) exist, some of which may cause multidrug-resistance. Ceftriaxone was first recommended as an option for uncomplicated gonococcal infections in 1985, and it is now a mainstay of therapy in all clinical practice guidelines. Ceftriaxone has consistently shown high microbiologic cure rates in clinical trials, and it has demonstrated an excellent safety profile. Although its use may be limited in patients with hypersensitivity to penicillins, the risk of using ceftriaxone in such patients is overestimated. The emergence of reduced ceftriaxone susceptibility in N. gonorrhoeae, coupled with a lack of diverse treatment alternatives and the limited pipeline of new antimicrobials, is a significant threat to the treatment of gonorrhea.

A new pathway for penicillin delabeling in Norway

Background

Penicillin allergy is self-reported by 3-10% of patients admitted to hospital. The label is wrong in 90% of the cases and has severe health implications. Penicillin-delabeling can reverse the negative effects of the label, and pathways adapted to local practice are needed. No tools are available in Norway for penicillin delabeling outside an allergy clinic.

Objective

To create and validate the first penicillin delabeling pathway applicable outside an allergy clinic in Norway.

Methods

An interdisciplinary taskforce created a penicillin allergy delabeling program (PAD) adapted to the Norwegian health care system. This was validated in a prospective, single-center study. Very low-risk and low-risk patients underwent a direct oral penicillin challenge and high-risk patients were referred for allergologic evaluation.

Results

One-hundred forty-nine patients declaring penicillin allergy were included. Seventy-four (50%) were very-low- and low risk patients suitable for a direct oral penicillin challenge resulting in only 1 mild reaction. Sixty high-risk patients were eligible for an oral penicillin challenge after allergologic evaluation; 3 patients reacted non-severely.

Conclusion

We have created and demonstrated feasibility of the first penicillin delabeling program (PAD) applicable in a hospital setting outside an allergy clinic in Norway. Our data suggest this is safe and beneficial, with 49% patients delabeled through a direct oral penicillin challenge, performed without any serious adverse events, and an overall 87% delabeling rate.

A pharmacist-led penicillin allergy de-labelling project within a preoperative assessment clinic: the low-hanging fruit is within reach

BACKGROUND

Having a false penicillin-allergy label is linked to longer hospital stays and to an increased risk of Clostridioides difficile and meticillin-resistant Staphylococcus aureus infection.

AIM

To assess a penicillin-allergy de-labelling tool designed for use by the non-allergist.

METHODS

Patients attending the surgical preoperative assessment clinic (POAC) at a large UK teaching hospital, who reported a penicillin allergy, were directly de-labelled by nursing or pharmacy staff, where appropriate. A penicillin-allergy de-labelling tool designed for use by the non-allergist was adapted and applied; nursing staff were provided with supporting information and education to enable removal of spurious labels. Antimicrobial pharmacists (AMPs) provided follow-up, cross-checked prophylactic antibiotics administered, interrogated clinical notes, and telephoned patients following their surgery, for details of any adverse reactions suffered.

FINDINGS

A total of 163 patients reporting a penicillin allergy were identified for intervention. Twenty-nine (17.8%) patients reported a penicillin-allergy history appropriate for direct de-labelling, of whom eight (27.6%) declined to consent. The remaining 21 patients (12.8%) were directly de-labelled, with 12 (7.4%) patients consenting during their POAC appointment; the remaining nine (5.5%) patients were consented and de-labelled after their surgery by an AMP.

CONCLUSION

The POAC was identified as an appropriate location and time-point in the patient pathway to enable the direct removal of spurious penicillin-allergy labels prior to surgery. Results suggest that this could be undertaken by nursing staff, although support from AMPs enabled a greater number of patients to be de-labelled.

Penicillin de-labelling in vancouver, British Columbia, Canada: comparison of approaches, outcomes and future directions

BACKGROUND

Inaccurate penicillin allergy labels lead to inappropriate antibiotic prescriptions and harmful patient consequences. System-wide efforts are needed to remove incorrect penicillin allergy labels, but more health services research is required on how to best deliver these services.

METHODS

Data was extracted from five hospitals in Vancouver, British Columbia, Canada from October 2018-May 2022. The primary outcomes of this study were to outline de-labelling protocol designs, identify the roles of various healthcare professionals in de-labelling protocols and identify rates of de-labelling penicillin allergies and associated adverse events at various institutions. Our secondary outcome was to describe de-labelling rates for special populations, including pediatric, obstetric and immunocompromised subpopulations. To achieve these outcomes, participating institutions provided their de-labelling protocol designs and data on program participants. Protocols were then compared to find common themes and differences. Furthermore, adverse events were reviewed and percentages of patients de-labelled at each institution and in total were calculated.

RESULTS

Protocols demonstrated a high level of variability, including different methods of participant identification, risk-stratification and roles of providers. All protocols used oral and direct oral challenges, heavily involved pharmacists and had physician oversight. Despite the differences, of the 711 patients enrolled in all programs, 697 (98.0%) were de-labelled. There were 9 adverse events (1.3%) with oral challenges with mainly minor symptoms.

CONCLUSIONS

Our data demonstrates that de-labelling programs effectively and safely remove penicillin allergy labels, including pediatric, obstetric and immunocompromised patients. Consistent with current literature, most patients with a penicillin allergy label are not allergic. De-labelling programs could benefit from increasing clinician engagement by increasing accessibility of resources to providers, including guidance for de-labelling of special populations.

Barriers to paediatric penicillin allergy de-labelling in UK secondary care: a regional survey

BACKGROUND

Incorrect penicillin allergy labels result in the use of inappropriately broad-spectrum antibiotics. De-labelling inaccurate penicillin allergy promotes antimicrobial stewardship and optimises prescribing practices. The objectives were to evaluate paediatric clinicians' knowledge and understanding of penicillin allergy and to identify barriers in tackling incorrect penicillin allergy labels.

METHODS

Paediatric clinicians from across the West Midlands of the UK were surveyed using an online, anonymised questionnaire between 1 August and 30 September 2021. Domains explored were (1) approach to penicillin allergy clinical vignettes, (2) knowledge of the impact of penicillin allergy labels, (3) frequency of allergy-focused history questions and (4) barriers in tackling incorrect penicillin allergy.

RESULTS

Responses were received from 307 paediatric clinicians across 12 hospitals. Sixty-one per cent would not prescribe a penicillin-based antibiotic if a family history of penicillin allergy was reported. There was an overall deficit in taking an allergy-focused history with only 36.5% inquiring about diagnostic confirmation. Absence, or lack of awareness of a referral pathway for antibiotic allergy evaluation (58.6%) and unfamiliarity of the indications for oral provocation testing (55%) were the most common reported barriers to penicillin allergy de-labelling. Fifty-one per cent would rather 'play it safe' than explore penicillin allergy confirmation as it is felt that alternative treatments were readily available.

CONCLUSIONS

The deficiency in antibiotic allergy-focused history among paediatric clinicians highlights the need for better allergy education across all clinical grades. Pragmatic algorithms and clear referral pathways could address barriers faced by non-allergists in de-labelling incorrect penicillin allergy.

Patients with questionable penicillin (beta-lactam) allergy: Causes and solutions

BACKGROUND

In Europe, North America, and Australia, 5% to 10% of the population are now classified as penicillin (β-lactam) allergic. Only ~ 10% of these questionable diagnoses, mostly made in childhood, can be confirmed by allergy diagnostics.

MATERIALS AND METHODS

The aim of this review is to show causes and consequences as well as recommendations for dealing with the often questionable diagnosis of penicillin (β-lactam) allergy (BLA).

RESULTS

An incorrect BLA diagnosis may negatively impact antibiotic treatment needed in the future, by using a less effective antibiotic or using a broad-spectrum antibiotic, for example, further exacerbating the problem of increasing antibiotic resistance. Accordingly, there is growing pressure from antibiotic stewardship programs to critically challenge the BLA diagnosis. Conservatively, a suspected BLA is reviewed by an allergist using medical history, skin testing, laboratory testing, and provocation. This clarification is costly and is not remunerated in the German health care system; that is the reason why this testing is only offered in a few specialized clinics and practically not at all in general practice. In view of thousands of affected patients, additional strategies are needed to treat patients with a low risk of hypersensitivity reaction despite suspected allergy with a β-lactam antibiotic. In recent years, various methods have been proposed to eliminate suspected allergy as promptly as possible and directly before necessary treatment with a β-lactam antibiotic, including standardized history (also in the form of an algorithm), skin test with immediate reading after 15 minutes, or administration of a small test dose. Investigations of small case series and also multi-center studies to date have yielded promising results in terms of feasibility and safety.

CONCLUSION

Of the large number of patients with (questionable) BLA, most have never been tested and - if antibiotic treatment becomes necessary - simply receive an alternative antibiotic. The diagnosis of BLA therefore requires new approaches besides classical allergy testing to critically question BLA.

Management of penicillin allergy in primary care: a qualitative study with patients and primary care physicians

Background

Six percent of patients are allergic to penicillin according to their medical records. While this designation protects a small number of truly allergic patients from serious reactions, those who are incorrectly labelled may be denied access to recommended first line treatment for many infections. Removal of incorrect penicillin allergy may have positive health consequences for the individual and the general population.

We aimed to explore primary care physicians’ (PCPs) and patients’ views and understanding of penicillin allergy with a focus on clinical management of infections in the face of a penicillin allergy record.

Methods

We conducted an interview study with 31 patients with a penicillin allergy record, and 19 PCPs in the North of England. Data were analysed thematically.

Results

Patients made sense of their allergy status by considering the timing and severity of symptoms. Diagnosis of penicillin allergy was reported to be ‘imperfect’ with PCPs relying on patient reports and incomplete medical records. PCPs and patients often suspected that an allergy record was incorrect, but PCPs were reluctant to change records. PCPs had limited knowledge of allergy services. PCPs often prescribed alternative antibiotics which were easy to identify. Both patients and PCPs differed in the extent to which they were aware of the negative consequences of incorrect penicillin allergy records, their relevance and importance to their lives, and management of penicillin allergy.

Conclusions

PCPs and patients appear insufficiently aware of potential harms associated with incorrect penicillin allergy records. Some of the problems experienced by PCPs could be reduced by ensuring the details of newly diagnosed reactions to antibiotics are clearly documented. In order for PCPs to overturn more incorrect penicillin records through appropriate use of allergy services, more information and training about these services will be needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-021-01465-1.

The role of a clinical pharmacist in spurious Penicillin allergy: a narrative review

Background A label of penicillin allergy is held by 6-10% of the general population and 15-20% of inpatients. > 90% of these labels are found to be spurious after formal allergy assessment. Carrying an unnecessary label of penicillin allergy is not benign. Such patients may receive second line, more expensive antibiotics, representing a significant impediment to antimicrobial stewardship. Aim of the review To (a) Explain the burden of spurious penicillin allergy, and evaluate the safety of direct oral penicillin challenge in 'low risk' patients (b) appraise the place for a clinical pharmacist-led penicillin allergy de-labelling programme. Method Narrative review. Search engines: PubMed, Google Scholar and Cochrane reviews. Search criteria: English language; search terms: penicillin allergy, antimicrobial stewardship, antimicrobial resistance, clostridium difficile, vancomycin resistant enterococci, risk stratification, clinical pharmacist and direct oral provocation test Results Penicillin allergy labels are associated with: longer hospital stay, higher readmission rates, enhanced risk of surgical site infections, risk of Clostridioides difficile infection and Methicillin resistant Staphylococcus aureus infection, a delay in the first dose of an antibiotic in sepsis and higher healthcare costs. A direct oral penicillin challenge in 'low risk' patients has proven to be safe. Discussion Recent studies including those led by a clinical pharmacist have demonstrated safety of a direct oral penicillin challenge in 'low risk' patients. This intervention needs validation within individual health services. Conclusion Direct oral penicillin challenge reduces the adverse impact of spurious penicillin allergy. A pharmacist-led penicillin allergy de-labelling program needs further validation in prospective multi-centre studies.

Genome-wide Study Identifies Association between HLA-B∗55:01 and Self-Reported Penicillin Allergy

Hypersensitivity reactions to drugs are often unpredictable and can be life threatening, underscoring a need for understanding their underlying mechanisms and risk factors. The extent to which germline genetic variation influences the risk of commonly reported drug allergies such as penicillin allergy remains largely unknown. We extracted data from the electronic health records of more than 600,000 participants from the UK, Estonian, and Vanderbilt University Medical Center's BioVU biobanks to study the role of genetic variation in the occurrence of self-reported penicillin hypersensitivity reactions. We used imputed SNP to HLA typing data from these cohorts to further fine map the human leukocyte antigen (HLA) association and replicated our results in 23andMe's research cohort involving a total of 1.12 million individuals. Genome-wide meta-analysis of penicillin allergy revealed two loci, including one located in the HLA region on chromosome 6. This signal was further fine-mapped to the HLA-B∗55:01 allele (OR 1.41 95% CI 1.33-1.49, p value 2.04 × 10-31) and confirmed by independent replication in 23andMe's research cohort (OR 1.30 95% CI 1.25-1.34, p value 1.00 × 10-47). The lead SNP was also associated with lower lymphocyte counts and in silico follow-up suggests a potential effect on T-lymphocytes at HLA-B∗55:01. We also observed a significant hit in PTPN22 and the GWAS results correlated with the genetics of rheumatoid arthritis and psoriasis. We present robust evidence for the role of an allele of the major histocompatibility complex (MHC) I gene HLA-B in the occurrence of penicillin allergy.

Sustaining and spreading penicillin allergy delabelling: A narrative review of the challenges for service delivery and patient safety

Many patients report allergies to penicillin, although in over 90% of these the label of penicillin allergy is shown to be incorrect following comprehensive testing. Inappropriate and inaccurate penicillin allergy labelling is a barrier to antimicrobial stewardship and can lead to patient harm. This review assesses an emergent evidence base and trend favouring delabelling using direct oral penicillin challenges following a stratified risk assessment of the likelihood and existence of true penicillin allergy, to identify and make recommendations for key components for implementation in standard practice. Research to date has focussed on the feasibility and clinical and financial outcomes of these direct delabelling strategies. There is a paucity of studies exploring the views and engagement of patients and healthcare professionals, and a gap in the evidence for prerequisites to safely deliver, sustain and spread the implementation of such services across health systems.