Direct oral amoxicillin challenge without antecedent penicillin skin testing in low-risk patients

Challenging dogmas: Intravenous versus oral beta-lactam antibiotic provocation tests

Background

Drug provocation tests (DPT) are considered the gold standard procedure to ascertain the diagnosis of beta-lactam (BL) allergy. Regarding route of administration, current recommendations prioritize oral challenges, considering them safer, and reserving the intravenous route for drugs for which this is the only formulation.

Objective

To compare in terms of tolerance and safety two protocols of BL DPT, using an oral protocol (OR-DPT) and an intravenous protocol (IV-DPT).

Methods

A descriptive, retrospective study was performed, including adult patients who underwent IV-DPT or OR-DPT for suspected immediate or delayed hypersensitivity to BL antibiotics, over a period of 4 years (between January 2018 and December 2021). Demographical data, index hypersensivity reactions' characteristics and tolerance to DPT were reviewed.

Results

A total of 1036 patients underwent DPT, mean age of 56.8 (standard deviation, SD, 17.8) years, 655 were women (63.2%). Immediate drug hypersensitivity reactions (DHR) had occurred in 564 of patients (54.4%). OR-DPT were performed in 439 (42.4%) and IV-DPT in 597 (57.6%). The frequency of reactions during DPT, regardless of the route used, was low (3.6%): only 16 (3.6%) in OR-DPT and 21 (3.5%) in IV-DPT. From IV-DPT, 16 out 21 DHR during DPT were immediate compared with 4 out of 16 in OR-DPT. Adjusted relative risk of developing a hypersensitivity reaction during IV-DPT versus OR-DPT was 1.13 (95% confidence interval (CI)0.57-2.22).

Conclusion

The results suggest that OR-DPT and IV-DPT are both safe procedures when adequately performed. However, IV-DPT protocols showed a higher rate of immediate DHR during DPT probably due to the selection of basal high-risk patients to undergo IV-DPT. In conclusion, IV-DPT may be considered as an option for challenges in drug-allergy studies, entailing a precise administration.

Low-risk penicillin allergy delabeling: a scoping review of direct oral challenge practice, implementation, and multi-disciplinary approaches

INTRODUCTION

Penicillin allergy is common, and there is increased clinician interest in direct oral challenge (DOC) as a testing strategy for low-risk penicillin allergy. To aid wider implementation of DOC, consensus definitions of low-risk penicillin allergy phenotypes, and standardized approaches to assessment, DOC procedures, and evaluation, are required.

AREAS COVERED

This review systematically reviews studies that have utilized penicillin DOC in healthcare settings to identify heterogeneity in implementation approaches and synthesize low-risk definitions, procedures, and evaluation.

EXPERT OPINION

Opportunity exists to standardize penicillin DOC procedures in patients with a low-risk penicillin allergy to optimize antimicrobial prescribing and reduce the burden of penicillin allergy. Standardizing the definitions of 'low-risk' and 'positive challenge,' and improving the evaluation of patient safety, alongside the development of a unified approach to the structure of undertaking an oral challenge, is likely to increase uptake and confidence among non-allergist clinicians.

Use of a beta-lactam graded challenge process for inpatients with self-reported penicillin allergies at an academic medical center

Background

The Antimicrobial Stewardship Program (ASP) at Nebraska Medicine collaborated with a board-certified allergist to develop a penicillin allergy guidance document for treating inpatients with self-reported allergy. This guidance contains an algorithm for evaluating and safely challenging penicillin-allergic patients with beta-lactams without inpatient allergy consults being available.

Methods

Following multi-disciplinary review, an order set for beta-lactam graded challenges (GC) was implemented in 2018. This contains recommended monitoring and detailed medication orders to challenge patients with various beta-lactam agents. Inpatient orders for GC from 3/2018-6/2022 were retrospectively reviewed to evaluate ordering characteristics, outcomes of the challenge, and whether documentation of the allergy history was updated. All beta-lactam challenges administered to inpatients were included, and descriptive statistics were performed.

Results

Overall, 157 GC were administered; 13 with oral amoxicillin and 144 with intravenous (IV) beta-lactams. Ceftriaxone accounted for the most challenges (43%). All oral challenges were recommended by an Infectious Diseases consult service, as were a majority of IV challenges (60%). Less than one in five were administered in an ICU (19%). Almost all (n = 150, 96%) were tolerated without any adverse event. There was one reaction (1%) of hives and six (4%) involving a rash, none of which had persistent effects. Allergy information was updated in the electronic health record after 92% of the challenges.

Conclusion

Both intravenous and oral beta-lactam graded challenges were implemented successfully in a hospital without a regular inpatient allergy consult service. They were well-tolerated, administered primarily in non-ICU settings, and were often ordered by non-specialist services. In patients with a self-reported penicillin allergy, these results demonstrate the utility and safety of a broadly adopted beta-lactam GC process.

De-labelling penicillin allergy in acutely hospitalized patients: a pilot study

Background

Penicillin allergy prevalence is internationally reported to be around 10%. However, the majority of patients who report a penicillin allergy do not have a clinically significant hypersensitivity. Few patients undergo evaluation, which leads to overuse of broad-spectrum antibiotics. The objective of this study was to monitor prevalence and implement screening and testing of hospitalized patients.

Methods

All patients admitted to the medical department in a local hospital in Oslo, Norway, with a self-reported penicillin allergy were screened using an interview algorithm to categorize the reported allergy as high-risk or low-risk. Patients with a history of low-risk allergy underwent a direct graded oral amoxicillin challenge to verify absence of a true IgE-type allergy.

Results

257 of 5529 inpatients (4.6%) reported a penicillin allergy. 191 (74%) of these patients underwent screening, of which 86 (45%) had an allergy categorized as low-risk. 54 (63%) of the low-risk patients consented to an oral test. 98% of these did not have an immediate reaction to the amoxicillin challenge, and their penicillin allergy label could thus be removed. 42% of the patients under treatment with antibiotics during inclusion could switch to treatment with penicillins immediately after testing, in line with the national recommendations for antibiotic use.

Conclusions

The prevalence of self-reported penicillin allergy was lower in this Norwegian population, than reported in other studies. Screening and testing of hospitalized patients with self-reported penicillin allergy is a feasible and easy measure to de-label a large proportion of patients, resulting in immediate clinical and environmental benefit. Our findings suggest that non-allergist physicians can safely undertake clinically impactful allergy evaluations.

What is new in beta-lactam allergy in children?

This review highlights the novelties in understanding the underlying immunologic mechanisms of drug hypersensitivity reactions (DHRs) with special reference to beta-lactams (BLs) in the pediatric population, as well as tiny changes in clinical classification and diagnosis of DHRs, in the last couple of years. BLs are still the most commonly prescribed and used antibiotics in children. Viral infections are very often in children, and they can provoke skin rashes which are difficult to differentiate from DHRs. The majority of children are incorrectly labeled as "allergic." Therefore, allergy to BLs in children is overdiagnosed. These children often receive suboptimal treatment with second-line broad-spectrum antibiotics, which are less effective, more costly, and associated with an increased risk of antibiotic-resistant infections. This prolongs hospitalization and thus more uses health care. The correct diagnosis of BL allergy in children is still an important and hot topic. This review has outlined the need for correct diagnosis of BL allergy in children and all the controversies encountered by pediatricians and pediatric allergists. It is also necessary to change the paradigm.

Towards a more precise diagnosis of hypersensitivity to beta-lactams - an EAACI position paper

A recent survey of the European Academy of Allergy and Clinical Immunology (EAACI) Drug Allergy Interest Group (DAIG) on how European allergy specialists deal with beta-lactam (BL) hypersensitivity demonstrated a significant heterogeneity in current practice, suggesting the need to review and update existing EAACI guidelines in order to make the diagnostic procedures as safe and accurate, but also as cost-effective, as possible. For this purpose, a bibliographic search on large studies regarding BL hypersensitivity diagnosis was performed by an EAACI task force, which reviewed and evaluated the literature data using the GRADE system for quality of evidence and strength of recommendation. The updated guidelines provide a risk stratification in BL hypersensitivity according to index reaction(s), as well as an algorithmic approach, based on cross-reactivity studies, in patients with a suspicion of BL hypersensitivity and an immediate need for antibiotic therapy, when referral to an allergist is not feasible. Furthermore, the update addresses availability and concentrations of skin test (ST) reagents, ST and drug provocation test (DPT) protocols, and diagnostic algorithms and administration of alternative BL in allergic subjects. Specifically, distinct diagnostic algorithms are suggested depending on risk stratification of the patient into high and low risk based on the morphology and chronology of the reaction, immediate (ie, occurring within 1-6 hours after the last administered dose) or nonimmediate (ie, occurring more than 1 hour after the initial drug administration), and the reaction severity. Regarding the allergy workup, the main novelty of this document is the fact that in some low-risk nonimmediate reactions ST are not mandatory, especially in children. For DPT, further studies are necessary to provide data supporting the standardization of protocols, especially of those regarding nonimmediate reactions, for which there is currently no consensus.

Safety of direct drug provocation testing in adults with penicillin allergy and association with health and economic benefits

BACKGROUND

Nonprescription of penicillin-containing antibiotics in patients diagnosed with penicillin allergy is associated with morbidity and mortality. Adverse reactions to penicillins comprise type A and B reactions.

OBJECTIVE

To assess the feasibility of penicillin allergy evaluation without penicillin skin testing (PST) for adult patients with type B reactions and the health and economic benefits of this process.

METHODS

Inpatients at an Australian tertiary hospital between April 1, 2017, and April 30, 2018, with a diagnosis of type B penicillin allergy, requiring a penicillin-containing antibiotic for treatment, were included. All patients underwent clinical history review, PST, and drug provocation testing (DPT).

RESULTS

Seventy-one patients were enrolled. Sixty-three reported a history of type B or unknown adverse reactions. No patients had a history of anaphylaxis requiring intubation or epinephrine within the last 10 years or a history suggesting Gell and Coombs type 2, 3, or 4 (severe) hypersensitivity reaction. Seven did not complete DPT because the treating team used a β-lactam antibiotic other than amoxicillin. Fifty-four of 56 remaining patients (96%) completed 3-day DPT to amoxicillin with no adverse reaction. Two experienced mild cutaneous reactions. Penicillin allergy evaluation was significantly associated with reduced length of stay, reduced hospital expenditure on bed and second-line antibiotics, and reduced readmission rates.

CONCLUSION

Penicillin allergy evaluation with DPT without PST may be feasible for all adult patients with a reported history of type B reactions to penicillins who do not have a history of anaphylaxis within the last 10 years or a type 2, 3, or 4 (severe) hypersensitivity reaction.