Drug allergy: A 2022 practice parameter update

Opioid Allergy Cross-Reactivity: A Retrospective Study Across Three Opioid Classes

IgE-mediated opioid hypersensitivities, or true allergies, are rare and most adverse reactions to opioids can be attributed to side effects or to pseudo-allergies. Given that immune-mediated allergies to opioids are uncommon, literature regarding cross-reactivity among opioid classes are limited. This retrospective study aimed to determine the rates of cross-reactivity and tolerance among patients with previously documented opioid allergy or adverse drug reaction (ADR) across three opioid drug classes (natural, semisynthetic, and synthetic opioids). Patients with documented allergy(s) and/or ADR(s) to opioids were assessed for outcomes of subsequent opioid exposure during any hospital admission at a Veterans Affairs hospital over a 10-year time-period. Veterans were sorted into three cohorts based on the opioid class of the previously documented allergy or ADR. Each cohort had three study arms, one for each class of subsequent opioid exposure. A total of 1507 patients were identified with previously documented allergy or ADR to at least one opioid and at least one subsequent opioid drug exposure. No cross-reactivity among any of the opioid drug classes were found resulting in 100% re-exposure tolerance rates with all study arms. These findings could increase confidence in utilizing opioids in patients with historically documented opioid allergies or ADRs.

Premature Discontinuation of Trimethoprim/Sulfamethoxazole Prophylaxis in Abdominal Transplant Recipients: A Deeper Dive

Trimethoprim/sulfamethoxazole (TMP/SMX) prophylaxis can prevent Pneumocystis jirovecii pneumonia (PJP) and other opportunistic infections (OI). We sought to assess the frequency, causative factors, and impact of early TMP/SMX discontinuation in abdominal solid organ transplant (SOT). This is a single-center, retrospective cohort study of abdominal SOT recipients at Mayo Clinic Arizona (MCA) between January 2021 and June 2023. Primary study goals were to determine the rate and reasons behind early TMP/SMX discontinuation and whether TMP/SMX prophylaxis was reinitiated. Secondary outcomes included mean duration of therapy, alternative prophylactic agent utilized, and incidence of TMP/SMX-preventable OI. A total of 930 abdominal SOT recipients were included (592 kidney, 253 liver, 85 multiorgan transplants). TMP/SMX was discontinued early in 184 (20%) patients: 77 kidney, 84 liver, 23 multiorgan. Predominant reasons for discontinuation were hyperkalemia (39%) and cytopenias (35%). Median duration of TMP/SMX prophylaxis before discontinuation was 54.5 (18.0, 93.2) days. TMP/SMX was not resumed in 62% of cases (36% kidney, 89% liver, 52% multi-organ). The predominant reason for non-resumption was alternative prophylaxis with no clear intent to rechallenge TMP/SMX (70%). Alternative prophylaxis included pentamidine (43%), none (30%), dapsone (22%), and atovaquone (5%). Of patients reinitiated, 86% (59/69) successfully remained on TMP/SMX through the prophylaxis period. One TMP-SMX-preventable OI (nocardiosis) was observed in the TMP/SMX discontinuation group. TMP/SMX is often discontinued prematurely in SOT recipients without resumption despite resolution of the offending cause. TMP/SMX prophylaxis should be maintained where possible, as alternative therapy may not offer the same broad spectrum of protection against OI.

Can Beta-Lactam Allergy De-Labeling Strategies Safely Empower Geriatric Care?

Background: Drug allergies constitute a significant health concern among the elderly, with beta-lactam (BL) antibiotics among the most frequently implicated agents. Nevertheless, data regarding the safety and efficacy of BL allergy de-labeling in this population remain scarce. This study aimed to evaluate the safety and efficacy of BL allergy assessment in a cohort of geriatric patients carrying BL allergy labels. Methods: We conducted a retrospective study, including patients aged >65 years who were referred for BL allergy evaluation at the Allergy Unit of Meir Medical Center. Patients underwent comprehensive anamnesis, skin testing, and, when indicated, oral challenge. Those successfully de-labeled were followed longitudinally to assess subsequent BL use and clinical outcomes. Results: Between 2009 and 2019, 166 elderly patients with suspected BL allergies were evaluated. A BL allergy was ruled out in 145 patients (87.3%). Sixteen patients (9.6%) were diagnosed with immediate-type hypersensitivity, 2.4% of patients had severe delayed-type hypersensitivity reactions, and one patient (0.6%) had a benign rash. The evaluation process was safe, with no severe reactions occurring during oral challenges, and no patient required hospitalization or epinephrine administration. A long-term follow up was available for 106 patients; among them, 38 (35.8%) received subsequent treatment with the previously suspected BL agent, without any reports of immediate or severe delayed reactions. Conclusions: Beta-lactam allergy de-labeling is safe and effective in the elderly and supports the critical role of allergy evaluation in this population. Enhanced awareness and implementation of de-labeling protocols in geriatric patients are warranted.

Implementation of a proposed algorithm to assess and de-label false penicillin allergy labels in the community

BACKGROUND

Community pharmacists could have a pivotal role to play in de-labelling false penicillin allergies or preventing false penicillin allergy labels from occurring to reduce inappropriate prescribing of less effective and broader-spectrum antibiotics.

METHODS

A quasi-experimental study aimed at implementing and evaluating an algorithm to assess and de-label false penicillin allergy labels in the community. Between April and May 2024, the algorithm was rolled out to five community pharmacies in Victoria, Australia. De-labelling outcomes of Type A reactions were recorded. Barriers and enablers to implementing the penicillin allergy assessment algorithm were also collected through semi-structured interviews.

RESULTS

Of 18,646 patients who presented to the pharmacies, 163 individuals (0.87 %) had a penicillin allergy label. Of these 163 patients, 30 (18.4 %) patients were assessed as having a Type A reaction (a non true allergy; non-immune related). All patients with Type A reactions were engaged in an attempt to de-label their allergy; 77 % of patients were accepting whilst 23 % were hesitant or non-receptive, due to time restraints or disbelief that their allergy is not a true allergy. Qualitative interview data revealed there remains a public misconception that antibiotic allergy labels do not impact the appropriateness of antibiotic prescribing or affect patient safety through increased risk of adverse drug events and antimicrobial resistance.

CONCLUSIONS

The proposed algorithm was able to support the de-labelleling of false penicillin allergies. Future research could implement the use of the algorithm in other primary care settings and ascertain the long-term retention of the initiation of de-labelleling in the community.

Cefazolin is Associated with a Lower Periprosthetic Joint Infection Risk than Alternative Antibiotic Regimens Following Total Hip Arthroplasty

INTRODUCTION

There have been conflicting reports on the risk of periprosthetic joint infection (PJI) with the use of alternative antibiotics to cefazolin following arthroplasty. We leveraged recent data from a nationally representative multi-payer dataset to investigate this question.

METHODS

We queried a healthcare dataset from 2016 to 2022 to identify primary total hip arthroplasties (THAs) using Current Procedural Terminology (CPT) and International Classification of Disease-Procedure Coding System (ICD-PCS) codes (27130, 0SR90xx, 0SRB0xx) with a corresponding osteoarthritis diagnosis (International Classification of Disease-Clinical Modification (ICD-CM): M16). Patient demographics, characteristics, and outcomes were extracted from existing dataset variables. The PJIs were defined using ICD-10 diagnosis codes from the Centers for Medicare & Medicaid Services' procedure-specific complication measure within 90 days of surgery. We compared PJI between patients receiving cefazolin antibiotic prophylaxis and patients who received an alternative antibiotic or cefazolin plus another antibiotic. The association between cefazolin use and PJI was evaluated using multinomial logistic regression. This study included 289,369 primary THA patients from 2016 to 2022. There were 25,164 patients (8.7%) who received a non-cefazolin antibiotic, 200,367 (69.2%) received cefazolin only, and 63,838 (22.1%) received cefazolin plus an alternative antibiotic.

RESULTS

In univariate analysis, there was a significant difference in the rate of 90-day PJI between the non-cefazolin group, cefazolin only, and cefazolin plus other antibiotic group (0.9, 0.5, and 0.5%, respectively, P < 0.001). In a logistic regression analysis that adjusted for age, sex, payer, race, ethnicity, and Elixhauser Comorbidity Index, the use of cefazolin only and cefazolin plus other antibiotic, were associated with reduced risk of 90-day PJI [OR (odds ratio) 0.62, 95% CI (confidence interval) (0.53 to 0.72), P < 0.001] and [OR 0.64, 95% CI (0.54 to 0.76), P < 0.001].

CONCLUSIONS

In this nationally representative multi-payer study using recent data, patients who received antibiotic prophylaxis with cefazolin had lower 90-day rates of PJI compared to those receiving alternative antibiotics during primary total hip arthroplasty.

Evaluation of direct oral provocation test results in mild cutaneous reactions to cephalosporins in children

Background: Cephalosporins are beta-lactam antibiotics commonly used in children and are the second most common cause of drug hypersensitivity reactions after penicillins. Antibiotic allergy is diagnosed by tests such as prick and intradermal skin tests and the drug provocation test (DPT). Skin tests can be challenging for both patients and clinicians. In appropriate cases, omitting these tests in favour of direct DPT may help to avoid diagnostic delays. Objective: Our study aimed to evaluate the results of direct DPT in children with a history of mild cutaneous reactions to cephalosporins. Methods: Between 2019 and 2024, pediatric patients with a documented history of mild cutaneous reactions to cephalosporins who underwent direct DPT without prior prick or intradermal skin testing were included in this study conducted at our clinic. Patients with systemic manifestations beyond cutaneous reactions at the time of the index reaction were excluded from the study. Results: The study included 128 patients who underwent direct DPT with cephalosporins. The most commonly suspected drugs were cefixime (45.3%), cefdinir (25.8%) and cefuroxime (18%). While 96.1% did not react, cephalosporin allergy was confirmed in 3.9% but all reactions were limited to skin involvement and none more severe than the index reaction. Conclusion: In our study, direct DPT ruled out suspected allergy in 96.1% of patients with a history of mild skin reactions to cephalosporins. In conclusion, direct oral DPT was found to be a safe and feasible approach for patients with isolated mild skin reactions, effectively bypassing the need for skin testing.

A Guide to Pediatric Antibiotic Allergy Testing: A Report From the US Drug Allergy Registry

Pediatric antibiotic labels are common, and unnecessary antibiotic avoidance is associated with negative personal and public health outcomes; as a result, there is an increasing emphasis on the importance of pediatric antibiotic allergy evaluations. Different testing strategies have been advised, including skin testing and challenge testing with varied doses and duration. Established consensus testing protocols are lacking. The US Drug Allergy Registry Pediatrics (USDAR-Peds) is a multisite prospective study designed for epidemiology and outcome evaluations of pediatric drug hypersensitivity reactions. Interpretation of multisite data requires a uniform clinical approach, and the USDAR-Peds standardized protocols were developed in response to this need. This rostrum aims to provide a rationale and framework for standardization for pediatric antibiotic allergy protocols and assessment of positive reactions through a pediatric-specific adaptation of the USDAR immediate reaction grading scale to create consistency for multisite research collaboration efforts such as USDAR-Peds.

Implementation of a pharmacist-led outpatient penicillin allergy testing clinic

BACKGROUND

Penicillin allergies affect approximately 10% of the population, leading to increased health care costs, treatment failures, and multidrug resistant organisms.

OBJECTIVE

To determine the feasibility of implementing a pharmacist-led outpatient penicillin allergy testing program.

METHODS

This single-site, retrospective cohort study was conducted from July 2022 through December 2023. The study site consisted of an outpatient clinic within a nonacademic community hospital. The primary outcome was the percentage of patients who had their penicillin allergy delabeled. Secondary outcomes included percentage of patients who received appropriate antibiotics following allergy delabeling, incidence and type of immunoglobulin E mediated penicillin reactions, number of patients who were relabeled with a penicillin allergy, number of orthopedic patients with a postoperative surgical site infection, average reimbursement per patient, and average appointment time.

RESULTS

A total of 457 outpatients received penicillin allergy testing during the study period. Physician specialties who referred patients were orthopedics, obstetrician-gynecologists, infectious disease, urology, urogynecology, cardiothoracic surgeons, and primary care providers. For the primary outcome, 439 patients (96%) were successfully delabeled. All delabeled patients received appropriate antibiotics following testing. There were 17 patients who developed minor itching with or without a localized rash following the amoxicillin challenge, and one patient had a delayed reaction of rash 12 hours after the amoxicillin that resolved with an antihistamine. One patient had their penicillin allergy relabeled. Of the 192 orthopedic patients, 0 patients had a postoperative surgical site infection. The average reimbursement was $423 per patient with the average appointment lasting 96 minutes.

CONCLUSION

Pharmacists, in collaboration with multiple physician specialties, successfully implemented an outpatient penicillin allergy testing service to safely delabel patients and support antimicrobial stewardship.

Penicillin Allergy Management in India and Sri Lanka: Current Challenges

Data regarding Penicillin allergy labels (PALs) from India and Sri Lanka are sparse. Emerging data suggests that the proportion of patients declaring an unverified PAL in secondary care in India and Sri Lanka (1%-4%) is lesser than that reported in High Income Countries (15%-20%). However, even this relatively small percentage translates into a large absolute number, as this part of the world accounts for approximately 25% of the global population. There is a huge unmet need for allergy specialists in India and Sri Lanka. Penicillin allergy management is further compromised by unavailability of skin test reagents, lack of formal training in drug allergy, pre-emptive, non-standardised and unregulated skin testing by untrained operators and a weak health service framework. This has an adverse impact on antimicrobial stewardship, particularly in the management of rheumatic fever, rheumatic heart disease, bacterial endocarditis, syphilis and other sexually transmitted infections. This narrative review highlights the burden of PALs in India and Sri Lanka, as well as gaps in the published literature. It describes current challenges and a pragmatic, cautious and staged bespoke mitigation approach to improve and standardise antimicrobial stewardship in accordance with the World Health Organisation AWaRe guidance.

New Approaches to Chemotherapeutic Drug Allergy: From Drug Challenge to Desensitization

This review explores the latest clinical advances in the evaluation and management of hypersensitivity reactions (HSRs) to chemotherapeutic agents. There is a critical need for standardized terminology and classification systems, and we discuss improved diagnostic tools and risk-management strategies that enhance the choice of using drug challenge or drug desensitization protocols. In addition, we examine established organizational models that promote patient safety and ensure continuity of care in oncology settings. By synthesizing current knowledge and practices, this review aims to provide a comprehensive overview of the state-of-the-art clinical approaches to managing HSRs to chemotherapeutic agents, ultimately contributing to better patient outcomes and quality of care. The insights presented here underscore the importance of ongoing research and collaboration among health care professionals to refine classification systems for drug HSRs and enhance the overall management of HSRs in oncology patients.

Postpartum Readmission after Unscheduled Cesarean Delivery in Patients with Class 3 Obesity

This study aimed to identify risk factors for postpartum readmission (PPR) in class 3 obese patients undergoing unscheduled cesarean deliveries.Retrospective cohort study of patients with a body mass index (BMI) of ≥40 kg/m2 undergoing unscheduled cesarean delivery from 2017 to 2020 comparing patients with and without PPR (unexpected admission, emergency room/overnight observation visit, unscheduled outpatient visit, or ambulatory surgery within 30 days). Medical history, operative data, and postpartum outcomes were compared between the cohorts.The electronic medical record was queried to identify cesarean deliveries documented as "unscheduled." In total, 255 of 1,273 identified patients (20.0%) had a PPR. Median BMI was similar between the cohorts (44.2 kg/m2, interquartile range [IQR]: [41.8, 47.9] vs. 44.8 kg/m2 [42.0, 48.9], p = 0.066). Readmitted patients were more likely to have a history of smoking during or prior to pregnancy (p = 0.046). A subgroup exploratory analysis excluding outpatient and emergency room visits demonstrated higher rates of type II diabetes mellitus in patients with PPR (11.5 vs. 4.6%, p = 0.030). Patients with readmission in comparison to those without readmissions were less likely to receive cefazolin prophylaxis (78.0 vs. 84.3%, p = 0.014) in comparison to gentamicin/clindamycin prophylaxis. Patients with readmission were less likely to have had vaginal preparation (56.9 vs. 64.3%, p = 0.027). On multivariable logistic regression analysis, smoking history (odds ratio [OR] = 1.44, 95% confidence interval [CI]: 1.06-1.96, p = 0.0220) and hypertensive disease (OR = 1.57, 95% CI: 1.18-2.09, p = 0.002) were associated with readmission. Cefazolin preoperative prophylaxis (OR = 0.59, 95% CI: 0.41-0.84, p = 0.004) and vaginal sterile preparation (OR = 0.72, 95% CI: 0.54-0.95, p = 0.022) were associated with decreased risk of readmission.In class 3 obese patients, a history of smoking and a diagnosis of hypertensive disease are associated with an increased risk of PPR. Perioperative antibiotic prophylaxis with cefazolin along with vaginal sterile preparation associate with a decreased risk of PPR. · Class 3 obesity and unscheduled cesarean deliveries are high risks for postpartum complications.. · Hypertensive disorders and smoking are associated with PPR.. · Cefazolin prophylaxis and vaginal preparation are associated with decreased PPR..

Research progress of anti-IGE treatment for allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) is an inflammatory reaction of the nasal mainly mediated by Immunoglobulin E(IgE). It is one of the most common chronic diseases in the world. Patients with nasal discomfort, persistent nasal itching, sneezing, runny nose and so on as the main symptoms, it is a refractory allergic disease, will seriously reduce the quality of life of patients.

OBJECTIVE

At present, the treatment of patients with allergic rhinitis is mainly to avoid contact with allergens, drug treatment and desensitization treatment. The serum IgE level of most patients is significantly increased. By introducing monoclonal antibodies into the gene-expression environment of IgE, the levels of free IgE can be effectively suppressed, resulting in a significant reduction in the incidence of AR. Therefore, this article will explore the mechanism and clinical application of this new anti-IgE drug, omalizumab.

CONCLUSION

Omalizumab can significantly relieve the condition of AR patients and reduce the dosage of corticosteroids and antihistamines, but its long-term efficacy and safety need further observation and analysis. Before use, the patient's status should be confirmed and the potential risks should be discussed with the patient in advance.

Nonallergist Delabeling-Should Penicillin Allergy Delabeling Only Be Performed by Allergists?

Penicillin allergy labels (PAL) are common but rarely correspond with a patient's likelihood to tolerate penicillin. This results in unnecessary penicillin avoidance in many patients, driving numerous negative health outcomes. Evaluation strategies for a PAL are driven by risk stratification and include a spectrum of modalities such as delabeling without any testing, direct oral challenge, and skin testing followed by challenge testing. Historically, PAL delabeling has primarily been the domain of the allergist, but this has resulted in significant limitations in access to testing for many patients globally and in the United States. Novel strategies to increase access to penicillin allergy evaluations are urgently needed, and nonallergist delabeling has been proposed as one strategy to help address this. Using a pro/con format, we review the evidence for nonallergist PAL delabeling in children and adults, focusing on direct challenge testing and highlighting considerations to guide nonallergist implementation of penicillin allergy evaluations.

Resensitization-Should Repeat Testing Be Performed in Patients Undergoing Penicillin Allergy Evaluations? A Pro-Con Debate

Evaluating penicillin allergy labels and expanding access to preferred treatment options safely is of critical public health importance. Most patients with penicillin allergy labels are not allergic, and even in those with verified allergy, sensitization wanes over time. However, sensitization is complex, and whereas a patient may have a negative penicillin allergy evaluation (including a drug challenge), resensitization can occur, raising a risk of a subsequent reaction on exposure. In this pro-con debate we deliberate on whether patients who have had negative penicillin allergy evaluations should undergo retesting for sensitization before subsequent administrations. The pro position is presented by Drs Inmaculada Doña, María Salas, and María Torres, whereas the con position is described by Drs Ami Belmont and Roland Solensky.

Single-cell immunopathology of recurrent acute generalized exanthematous pustulosis associated with vancomycin

Background

Acute generalized exanthematous pustulosis (AGEP) is a severe cutaneous adverse reaction to medication that presents within 72 hours of exposure with erythematous papules and plaques with overlying pustules. The immunopathogenesis and predisposing factors of AGEP are not well characterized.

Objective

To better understand the genetic risk factors and single-cell immunopathogenesis of AGEP, we longitudinally characterized a patient with recurrent AGEP after an initial episode triggered by vancomycin.

Methods

A clinical timeline over an 8-year period was paired with skin testing, histopathology, and immunogenetic and other testing at 3 time points. Skin biopsies performed on affected skin (positive vancomycin-delayed intradermal testing [IDT]) and unaffected control skin 8 years after the initial event were subjected to single-cell sequencing to measure gene and protein expression.

Results

The patient was HLA-A∗32:01 positive, which has been associated with vancomycin-induced drug reaction with eosinophilia and systemic symptoms. IDT remained positive over time, despite recurrent reactions without drug exposure. Clinical features and histopathology of IDT-positive skin were consistent with AGEP. Single-cell analysis of affected skin showed polyclonal TH17-like cells with gene expression signatures similar to T-cell response during prevalent infectious diseases.

Conclusions

This patient exhibited persistent vancomycin-positive IDT despite distinct nondrug episodes of ALEP/AGEP. This suggests that AGEP may be triggered by both antigen-specific and non-antigen-specific factors. AGEP-affected skin showed an inflammatory infiltrate with a TH17-like effector population, which may represent potentially actionable targets for therapeutic intervention. The presence of HLA-A∗32:01, a defined risk factor for vancomycin-induced drug reaction with eosinophilia and systemic symptoms, may indicate a shared predisposition, warranting further study.

Management and Prevention of Hypersensitivity Reactions to Radiocontrast Media: A Consensus Statement from the American College of Radiology and the American Academy of Allergy, Asthma & Immunology

Intravenous iodinated contrast media (ICM) is widely used in the United States, and it is imperative to provide guidance on the management of adverse reactions to ICM as well as the preparation, planning, and potential premedication for patients with previous reactions. Currently there is a discordance between the American College of Radiology Contrast Manual, which recommends premedication to prevent repeat hypersensitivity reactions to ICM, and the Anaphylaxis 2020 Practice Parameters Update, which recommends against routine administration of glucocorticoids and/or antihistamines to prevent anaphylaxis with prior ICM hypersensitivity reactions. A task force of experts from radiology who are also members of the American College of Radiology Committee on Drugs and Contrast Media and expert allergists/immunologists including members of the Adverse Reactions to Drugs, Biologics and Latex Committee of American Academy of Allergy, Asthma & Immunology evaluated the scientific evidence to develop consensus recommendations that are endorsed by both organizations. The task force took into account the strength of evidence and balanced the potential risks of recurrent reactions with those of premedication and product avoidance when making these recommendations to improve and standardize the care of patients who experience or have a history of reaction to ICM. © Radiological Society of North America and American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc on behalf of American Academy of Allergy, Asthma & Immunology and by Radiological Society of North America. All rights are reserved, including those for text and data mining, AI training, and similar technologies. This paper was jointly developed by The Journal of Allergy and Clinical Immunology: In Practice, Radiology and jointly published by Elsevier Inc and Radiological Society of North America. The articles are identical except for minor stylistic and spelling differences in keeping with each journal's style. Either citation can be used when citing this article. Keywords: Contrast allergy, Contrast hypersensitivity, Iodinated contrast allergy, Iodinated contrast hypersensitivity, Anaphylaxis, Contrast skin testing, Contrast switching, Contrast reaction, Delayed contrast reaction, Immediate contrast reaction.

Diagnostic Accuracy of Skin Test in Patients With Cefaclor-Induced Anaphylaxis

BACKGROUND

The frequency of cefaclor-induced immediate hypersensitivity reactions has increased in Korea. Skin prick tests (SPTs) and intradermal tests (IDTs) using cephalosporins are not as well validated as those using penicillin. Limited data are available regarding the diagnostic value of SPTs and IDTs for cefaclor-induced immediate hypersensitivity reactions.

OBJECTIVE

To compare the clinical utility of the SPT and IDT with that of the ImmunoCAP test in patients with cefaclor-induced immediate hypersensitivity reactions.

METHODS

We conducted a retrospective analysis of participants from a tertiary hospital in Korea with a history of suspected immediate hypersensitivity reaction to cefaclor who had undergone SPT, IDT, and ImmunoCAP.

RESULTS

A total of 155 patients with a diagnosis of cefaclor-induced immediate hypersensitivity reactions were included in the analysis. Of those, 81 patients tested positive for both the SPT/IDT and the ImmunoCAP test. Sixty patients were positive for the SPT/IDT but negative for the ImmunoCAP test. Seven patients tested positive only for the ImmunoCAP test. Positivity for SPT/IDT and that for SPT were significantly higher in cases of anaphylaxis compared with urticaria; however, ImmunoCAP positivity did not differ based on the severity of the reaction.

CONCLUSIONS

Skin prick tests and IDTs are more sensitive than ImmunoCAP for diagnosing cefaclor-induced immediate hypersensitivity reactions, particularly in cases of anaphylaxis. The positivity of SPT/IDT varies depending on the severity of the hypersensitivity reaction. Therefore, SPT/IDT should be considered for diagnosing cefaclor-induced anaphylaxis.

Direct Amoxicillin Challenges for Penicillin Allergy Through Pediatric Primary Care Group Visits: A Pilot Study

Novel strategies are needed to expand equitable access to penicillin allergy testing. We performed a pilot study of penicillin allergy testing through direct challenges performed at pediatric primary care group office visits. Ninety-five percent of subjects were delabeled with no severe reactions noted, providing conceptual basis for further implementation studies.

An Economic Evaluation of Direct Oral Penicillin Challenge for De-Labelling Low Risk Patients With a Penicillin Allergy Label

BACKGROUND

Removing inaccurate penicillin allergy labels (PALs) can reduce unnecessary exposure to 'watch' and 'reserve' groups of antibiotics and thereby reduce antimicrobial resistance. The most efficient model for a non-allergy-specialist-led penicillin allergy de-labelling (PADL) service has not been established.

OBJECTIVE

To determine the costs to the UK National Health Service of a direct oral penicillin challenge (DPC) for low-risk patients with a PAL in three hospitals in England, each with a different non-allergy-specialist delivery model: pharmacist-led, nurse-led, and mixed multidisciplinary.

METHODS

Cost analysis of the DPC pathway, including resources related to staff time and antibiotics. The effect of de-labelling on healthcare utilisation over 5 years was modelled using data from the published literature.

RESULTS

In total, 2257 patients from the Acute Medical or Infectious Disease Unit (AMU/IDU), Pre-surgical, and Haematology-Oncology departments were screened. Subsequently, 126 underwent DPC, and 122 were de-labelled. Twenty-two of these were de-labelled in time to affect their antibiotic regimen; 6 from AMU/IDU and 16 Pre-surgery. The DPC represented 22%-23% of the pathway cost in the pharmacist-led and mixed models, and 15% in the nurse-led model. Across departments and models, the cost per de-labelled patient varied between £577 (95% Credible Interval: 370, 633) for haematology-oncology patients to £2329 (947, 19,504) for AMU/IDU patients, both under the nurse-led model. After 5 years, recouping costs was unlikely for AMU/IDU patients under any model or for all patients combined under the mixed model.

CONCLUSIONS

The penicillin allergy de-labelling pathway cost was  ≥ 4-fold that of the DPC alone. Costs were up to 3 times higher in an acute compared to an elective setting. No short-term cost savings were identified from proactive or opportunistic penicillin allergy de-labelling in this study.

Derivation and Validation of an Electronic Health Record Penicillin Allergy De-Labeling Prevalence Measure

With no standard method to capture penicillin allergy de-labeling prevalence across populations, we developed and validated a simple penicillin allergy de-labeling prevalence measure from electronic health records that achieved perfect sensitivity (100.0%), high specificity (99.4%), and strong agreement with a comprehensive algorithm that included free-text manual review (kappa = .997).

The Discrepancy Between Perceived and Proven Drug Hypersensitivity in a Well-Defined Cohort of Patients With Inborn Errors of Immunity

BACKGROUND

Inborn errors of immunity (IEI) are genetic disorders characterized by recurrent and/or severe infections, autoimmunity, autoinflammation, allergies, and cancer. Despite frequent drug exposures due to recurrent infections and comorbidities, the prevalence and characteristics of drug hypersensitivity reactions (DHR) in pediatric patients with IEI remain understudied.

METHODS

This multicenter, cross-sectional study evaluated 264 pediatric patients with IEI along with a control group (CG) comprising 443 age-matched controls using a stepwise diagnostic approach, including the patient-reported Study Questionnaire (Study-Q), the European Network for Drug Allergy Questionnaire (ENDA-Q), and confirmatory diagnostic testing, including skin testing and drug provocation tests (DPT). The demographic, clinical, and allergic profiles of the IEI patients and CG were compared.

RESULTS

IEI patients (57.6% male) had a median current age of 10 years, with combined immunodeficiencies being the most common phenotype (53.4%). The number of courses for antibiotic use and hospitalization was more frequent in IEI patients compared to CG (p < 0.001). DHR was more common in IEI patients according to Study-Q (p < 0.001) and ENDA-Q (p = 0.002), although proven DHR as a result of confirmatory testing was comparable with CG (1.1% vs. 0.4%, p = 0.368). Despite the fact that suspected DHR in IEI patients was most frequently associated with beta-lactams (47.6%), with 73.9% presenting with urticaria, proven DHR mainly included reactions to radiocontrast agents (n = 2) and ibuprofen (n = 1).

CONCLUSION

Although drug hypersensitivity is often suspected in patients with IEI, proven cases are rare. Standardized protocols, including DPT in drug allergy centers, are essential to differentiate proven allergies from nonallergic reactions, ensure effective treatment, and avoid unnecessary drug restrictions in this unique population.

Penicillin allergies and selection of intrapartum antibiotic prophylaxis against group B Streptococcus at a safety-net institution

OBJECTIVES

To evaluate the rate of documented penicillin allergies in obstetric patients and to estimate the proportion of patients receiving inappropriate alternative intrapartum Group B Streptococcus (GBS) prophylaxis.

METHODS

This was a retrospective cohort study of patients delivering at Denver Health Medical Center (DHMC) between April 27, 2017 and October 31, 2022. The study included all patients with documented penicillin allergy and GBS positive status during routine prenatal care. Records were reviewed for allergy severity/risk and antibiotic administered for GBS prophylaxis. Allergy severity/risk was based on whether there was a documented reaction in the electronic health record and the presence or absence of anaphylaxis, angioedema, respiratory distress, or urticaria. Patients were classified as receiving appropriate or inappropriate intrapartum antibiotic prophylaxis based on their allergy risk stratification and whether they received standard (e.g. penicillin, cefazolin) or alternative (e.g. clindamycin, vancomycin) antibiotics. The primary outcome was inappropriate prophylaxis, defined as receiving an alternative antibiotic in the setting of a low-risk penicillin allergy. Secondary maternal and neonatal outcomes were abstracted and compared based on appropriateness of antibiotic selection.

RESULTS

There were 18,931 unique patient encounters during the study period, of whom 1,262 (6.7 %) had a documented penicillin allergy. Of patients with penicillin allergies, 196 were GBS-colonized. Of the 86 GBS-colonized patients with low-risk penicillin allergies, 54 (62.8 %) received inappropriate antibiotic prophylaxis (i.e. received alternative antibiotics despite a low-risk allergy). Fewer than 7 % of pregnant patients developed complications, including chorioamnionitis, endometritis, or surgical site infection within 30 days. Only one neonate was diagnosed with GBS bacteremia.

CONCLUSIONS

More than half of GBS-colonized patients with low-risk penicillin allergies at our institution received inappropriate intrapartum antibiotic prophylaxis. These data support the need for improved documentation of allergy type and severity and antibiotic selection to expand adherence to guideline recommendations.

Impact of sulfonamide allergy label on clinical outcomes of acute cystitis: a retrospective matched cohort study

BACKGROUND

Cystitis is a common infection in an otherwise healthy individual. Sulfonamide antibiotics are first-line treatment options. Sulfonamide allergy label (SAL) is the second most common antibiotic allergy label in electronic health records, yet its impact on clinical outcomes in patients with cystitis is not well-characterised.

AIMS

The aim of this study is to characterise the impact of SAL on clinical outcomes of acute cystitis.

METHODS

In this retrospective matched cohort study utilising the TriNetX US Collaborative Network (Cambridge, MA, USA), adult patients with cystitis were categorised based on their SAL status. The 28-day risks of acute pyelonephritis and Clostridium difficile infection and the risk of recurrent or relapsed cystitis (defined as cystitis 15-28 days post-indexed cystitis) were contrasted. Antibiotic prescription practices within 14 days of the index cystitis were also compared.

RESULTS

When comparing 19 767 patients with cystitis and SAL to an equal number of matched controls, more patients with SAL had acute pyelonephritis (RR 1.27; 95% CI 1.08-1.48; P = 0.003; corrected P = 0.027) within 28 days of index. More patients with SAL developed recurrent/relapsed cystitis 15-28 days post-indexed cystitis (RR 1.19; 95% CI 1.08-1.31; P = 0.001; corrected P = 0.009) as compared to controls. SAL altered antibiotic prescription practices with under-utilisation of trimethoprim and sulfamethoxazole and increased utilisation of alternative antibiotics, including fluoroquinolones and nitrofurantoin, which was associated with an increased risk of Clostridium difficile infection.

CONCLUSIONS

SAL alters antibiotic prescription practices and is associated with a slightly increased risk of poor outcomes in adult patients with cystitis.

Preventing Orthopedic Infections

The prevention of orthopedic infections is of critical importance to improve patient outcomes and reduce health care costs. Preventative strategies can be employed preoperatively, including mitigation of medical risk factors, methicillin-resistant Staphylococcus aureus decolonization, appropriate skin preparation, and optimizing perioperative antimicrobial prophylaxis; intraoperatively, including utilizing irrigation, topical antibiotics, infection control measures, and timely debridement/optimal surgical techniques; and postoperatively, including consideration of antibiotic duration after primary arthroplasty and reimplantation. This article provides an evidence-based discussion of these strategies while also highlighting areas where ongoing research may be beneficial.

Building an allergy reconciliation module to eliminate allergy discrepancies in electronic health records

OBJECTIVE

Accurate, complete allergy histories are critical for decision-making and medication prescription. However, allergy information is often spread across the electronic health record (EHR); thus, allergy lists are often inaccurate or incomplete. Discrepant allergy information can lead to suboptimal or unsafe clinical care and contribute to alert fatigue. We developed an allergy reconciliation module within Mass General Brigham (MGB)'s EHR to support accurate and intuitive reconciliation of discrepancies in the allergy list, thereby enhancing patient safety.

MATERIALS AND METHODS

We combined data-driven methods and knowledge from domain experts to develop 5 mechanisms to compare allergy information across the EHR and designed a user interface to display discrepancies and suggested reconciliation actions, with links to relevant data sources. Qualitative and quantitative analyses were conducted to assess the module's performance and measure user acceptance.

RESULTS

We implemented and tested the proposed allergy reconciliation mechanisms and module. A comprehensive integration workflow was developed for the module, which was piloted among 111 primary care physicians at MGB. F1 scores of the reconciliation mechanisms range from 0.86 to 1.0. Qualitative analysis showed majority positive feedback from pilot users.

DISCUSSION

Our allergy reconciliation module achieved high performance, and physicians who used it largely accepted its recommendations. However, 56% of the pilot group ultimately did not use the module. User engagement and education are likely needed to increase adoption.

CONCLUSION

We built a module to automatically identify discrepancies within patients' allergy records and remind providers to reconcile and update the allergy list. Its high accuracy shows promise for enhancing patient safety and utility of drug allergy alerts.

The use of perioperative cephalosporin prophylaxis in patients who have a pre-existing penicillin allergy

BACKGROUND

Studies have shown an association between a reported penicillin allergy and an increased risk of surgical site infection. The risk is due to avoidance of cephalosporins and to the use of alternative classes of antibiotics in surgical prophylaxis. The aim of this study was to examine the safety of using cephalosporins in patients with a penicillin allergy label.

METHODS

Patients with a primary or revision hip or knee arthroplasty in a tertiary care hospital between March 2020 and February 2023 were identified (n = 14,939). Information on prophylactic antibiotics, pre-existing antibiotic allergy labels before the operation, and all recorded new antibiotic allergy labels within 2 weeks after the operation was gathered. The prophylactic antibiotic use in patients with and without a penicillin allergy label was compared. In addition, all new antibiotic allergy labels recorded after the operation were verified from the electronic health records.

RESULTS

A total of 1,435 (9.6%) patients had a previous penicillin allergy label. The majority of patients (14,838 of 14,939; 99.3%) received cephalosporin prophylaxis, as did most of the patients with a label of penicillin allergy (1,395 of 1,435; 97.2%). Six perioperative allergic reactions were recorded; none of these were anaphylactic reactions. In 5 cases, the allergic reaction occurred in patients receiving cefuroxime, none of whom had a previous penicillin allergy.

CONCLUSION

This study found cephalosporin antibiotic prophylaxis to be safe in patients with a pre-existing penicillin allergy label.

Reducing Unnecessary Penicillin Allergy Labels in the Pediatric Surgical Population

BACKGROUND

Up to 10% of children report having a penicillin allergy; however many of these are misdiagnoses or the allergy resolves over time. Having an unnecessary penicillin allergy label increases risk of adverse clinical outcomes and increased health care costs.

LOCAL PROBLEM

At our local pediatric surgical center, the percentage of patients with a penicillin allergy label was 7%.

METHODS

A pre/postimplementation design was used.

INTERVENTIONS

Pediatric surgical patients with a penicillin allergy label were identified and risk-stratified to undergo a single-dose oral provocation test (OPT) to amoxicillin.

RESULTS

Forty-two patients underwent an OPT. The percentage of patients with a penicillin allergy label decreased to 6.4% after 6 months ( P = .045). Median wait time for an allergy evaluation decreased from 102 to 42 days ( P < .0001).

CONCLUSIONS

This quality improvement project decreased penicillin allergy labeling rates in pediatric surgical patients, improved access to penicillin allergy evaluation, and had no adverse outcomes.

PEN-FAST-ED: Utilizing the PEN-FAST decision tool to guide antibiotic prescribing in the emergency department

BACKGROUND

Patient-reported penicillin allergies are frequently encountered in the emergency department (ED), which often lead to non-beta-lactam antibiotic use despite beta-lactams' place as first-line therapy in most bacterial infections. The PEN-FAST clinical decision tool was developed and validated to identify patients with a low risk of true penicillin allergies that do not require formal skin testing for rechallenging. The tool consists of four questions that add up to a total score ranging from 0 to 5. Scores of 0-2 are associated with low risk of true penicillin allergy (<5% risk of true reaction); scores of 3 with moderate risk (<20% risk); and scores of 4-5 with high risk (50% risk). The purpose of our study was to determine the safety and efficacy of our facility's implementation of pharmacist utilization of the PEN-FAST screening tool to assess purported penicillin allergies and rechallenge low to moderate risk patients in the ED.

METHODS

This was a single-center, prospective, observational cohort study conducted from October 2023 to March 2024. Adult ED patients with a documented penicillin allergy with an order for aztreonam, levofloxacin, clindamycin, or a consult for pharmacy to assist with antibiotic selection were included. Patients were excluded if the order or consult was placed by a non-ED physician, no penicillin allergy was documented, the patient had previously tolerated a penicillin or cephalosporin per chart review, was unable to participate in the interview, or the completion of the assessment would delay patient care. The primary outcome was the percent of patients with a PEN-FAST score of 0-2 who tolerated a beta-lactam antibiotic after pharmacist intervention. Secondary safety and logistical outcomes included the incidence of immune-mediated reactions within one hour of beta-lactam administration, timing of the assessment, and antibiotic selection in transitions of care.

RESULTS

Of the 361 patients screened, 100 patients were included. There were 61% of patients who had a PEN-FAST score of 0-2, 30% had a score of 3, and 9% had a score of 4-5. For the primary outcome, all 52 (100%) patients with a PEN-FAST score of 0-2 who were rechallenged tolerated a beta-lactam antibiotic in the ED. For secondary outcomes, 6 patients with PEN-FAST score of 3 were rechallenged and tolerated a beta-lactam. There were 0 incidences of any immune-mediated reactions within one hour of beta-lactam administration. The median time from initial order placement to change in therapy and to antibiotic administration was 17 min and 41 min, respectively. Of those rechallenged, 13 of 14 discharged (93%) and 39 of 44 admitted patients (89%) were continued on beta-lactam antibiotics.

CONCLUSION

In this prospective, observational study, administration of beta-lactam antibiotics to ED patients with previously reported penicillin allergies and a PEN-FAST score less than 3 did not result in any immune-mediated reactions. The PEN-FAST decision tool was able to safely identify and risk-stratify eligible patients for beta-lactam rechallenge in the ED.

Assessing the safety of increased outpatient cephalosporin use following the modification of penicillin allergy cross-reactivity alerts

BACKGROUND

Concerns about penicillin-cephalosporin cross-reactivity have historically led to conservative prescribing and avoidance of cephalosporins in patients with penicillin allergy labels, potentially causing suboptimal outcomes. Recent evidence suggests a lower risk of cross-reactivity, prompting a reassessment of alert systems.

OBJECTIVE

To assess the impact of limited penicillin cross-reactivity alerts on outpatient cephalosporin use and the incidence of adverse reactions in a healthcare setting.

METHODS

This retrospective cohort study compared cephalosporin prescribing and adverse reactions in patients labeled as penicillin-allergic before and after limiting penicillin cross-reactivity alerts in the electronic medical record at a large academic medical center.

RESULTS

Among 17,174 patients (8,131 pre- and 9,043 post-implementation), there was a statistically significant increase in outpatient cephalosporin prescribing by 8% (P < .001). The use of alternative antibiotic classes decreased. There was no statistically significant increase in adverse events pre- and post-implementation (0.036%-0.058%, P = .547), and no severe events were attributable to cross-reactivity. The alert modification reduced alerts by 92% (P < .001).

CONCLUSION

The reduction of penicillin-cephalosporin cross-reactivity alerts was associated with increased cephalosporin use, without a significant increase in adverse reactions. This demonstrates that the practice is safe and decreases alert burden.

Management and Prevention of Hypersensitivity Reactions to Radiocontrast Media: A Consensus Statement From the American College of Radiology and the AAAAI

Intravenous iodinated contrast media (ICM) is widely used in the United States, and it is imperative to provide guidance on the management of adverse reactions to ICM as well as the preparation, planning, and potential premedication for patients with previous reactions. Currently there is a discordance between the American College of Radiology Contrast Manual, which recommends premedication to prevent repeat hypersensitivity reactions to ICM, and the Anaphylaxis 2020 Practice Parameters Update, which recommends against routine administration of glucocorticoids and/or antihistamines to prevent anaphylaxis with prior ICM hypersensitivity reactions. A task force of experts from radiology who are also members of the American College of Radiology Committee on Drugs and Contrast Media and expert allergists/immunologists including members of the Adverse Reactions to Drugs, Biologics and Latex Committee of American Academy of Allergy, Asthma & Immunology evaluated the scientific evidence to develop consensus recommendations that are endorsed by both organizations. The task force took into account the strength of evidence and balanced the potential risks of recurrent reactions with those of premedication and product avoidance when making these recommendations to improve and standardize the care of patients who experience or have a history of reaction to ICM.

Sleep dysfunction in aspirin exacerbated respiratory disease: A prospective cohort study

Objective

Studies have described sleep dysfunction (SD) in patients with chronic rhinosinusitis (CRS). However, there is a paucity of literature describing sleep dysfunction in the context of aspirin-exacerbated respiratory disease (AERD). The purpose of this study was to evaluate the prevalence and severity of SD in patients with AERD relative to CRS.

Methods

This study is a prospective cohort study. Patients diagnosed with CRS without polyposis (CRSsNP, n = 206), CRS with nasal polyposis (CRSwNP, n = 38), and AERD (n = 28) were recruited prospectively in academic center rhinology clinic. SD was assessed using the Neuro-QOL Short Form v1.0-Sleep Disturbance (sleep-QOL), for which severe SD is defined as a score >2.0 standard deviations from the normalized mean. Demographic and patient-reported outcome measures (including SNOT-22 and PHQ-2) were collected to adjust for sleep confounders. Comparisons were made between groups using univariate and multivariate analyses.

Results

The prevalence of severe SD was significantly higher in AERD (57.1%) than in CRSsNP (32.5%) or CRSwNP (34.2%), p = 0.038. After adjusting for sleep confounders, the risk of sleep dysfunction remained higher among patients with AERD (odds ratio [OR] = 2.72 vs. CRSsNP, 95% confidence interval [CI] = 1.18-6.27, p = 0.02; OR = 3.06 vs. CRSwNP, 95% CI = 1.06-8.82, p = 0.04). SNOT-22 total score and the sleep subdomain showed no correlation with sleep-QOL score.

Conclusions

The frequency and severity of SD are greater in AERD patients than in patients with CRS with or without nasal polyposis, independent of confounders of sleep quality. While the putative link between AERD and SD remains elusive, this study suggests that SD in AERD may be greater than previously recognized.

Development of a drug allergy alert tiering algorithm for penicillins and cephalosporins

INTRODUCTION

Limited research is available regarding recommendations about which drug allergy alerts (DAAs) in clinical decision support (CDS) systems should interrupt provider workflow. The objective was to evaluate the frequency of penicillin and cephalosporin DAA overrides at two institutions. A secondary objective was to redesign DAAs using a new tiered alerting system based on patient factors.

METHODS

A retrospective, observational study evaluated CDS DAA overrides for penicillins and cephalosporins at two large academic medical centers. Included patients were at least 18 years of age and had a penicillin or cephalosporin DAA fired at the time of medication ordering. We developed a rule-based algorithm to classify DAAs into three groups: no alerts presented to user, non-interruptive (informational) alerts, and interruptive alerts requiring a coded response. The rule-based algorithm includes drug class or cross-sensitivity matches and reaction types with designated severities (high, medium, or low).

RESULTS

DAAs for penicillin and cephalosporins were overridden 55% of the time at each institution. Of the DAAs overrides, 85% were cross sensitivity matches and 15% were drug class matches. Reactions were classified as 22% high severity, 29% medium, and 48% low. Most low severity reactions were rash (25%), unspecified reactions with no comments (13%), nausea/vomiting (4%), and GI upset (3%). High severity reactions were mostly other reactions with comments (19%) and anaphylaxis (4%). Approximately 30% of the penicillin and cephalosporin alert overrides could have been non-interruptive alerts based on the penicillin or cephalosporin allergic reaction documented in the EHR at each institution.

CONCLUSION

The majority of penicillin and cephalosporin DAAs were overridden, largely for cross sensitivity in lower severity reactions. The data can be used to inform DAA redesign, reduce override rates, and improve patient safety.

Diagnosis and clinical management of drug allergies in obstetrics and gynecology: an expert review

Drug allergies, specifically antibiotic allergies, are frequently encountered in obstetrics and gynecology, with 10% of the US population reporting a penicillin allergy. This poses a particular challenge to the obstetrician-gynecologist, as beta-lactam antibiotics are indicated as first-line therapy for the treatment and prevention of most specialty-specific infections. Alternative antibiotic use in the setting of a reported allergy is not benign and has been associated with increased cesarean delivery, endometritis, wound complication, length of hospital stay in pregnant patients, Group B Streptococcus sepsis, neonatal length of stay, neonatal laboratory draw in neonates born to patients with allergies, and surgical site infection in gynecologic patients. Furthermore, alternative antibiotic use leads to increased antibiotic resistance, toxicity, and healthcare cost. In addition, the administration of antibiotics in a patient with a history of type I immediate hypersensitivity reaction poses a risk of anaphylaxis with repeat exposure. Fortunately, >90% of patients who report a penicillin allergy are not truly allergic and would tolerate penicillins if administered. This can be due to either mislabeling of the index reaction as an allergy (when it was due to a drug intolerance or a viral exanthem) or waning immunoglobulin E-mediated immunity over time. Given this, allergy evaluation is widely recommended, even in pregnancy. Allergy evaluation involves detailed patient history and allergy testing with skin testing and/or oral challenge, as appropriate. These tools have been found to be safe and effective in gravid and nongravid individuals and to result in increased use of first-line antibiotics when used appropriately. Furthermore, even in the setting of a true penicillin allergy, cross-reactivity with cephalosporins is extremely low and estimated at 2% to 3% among patients with a verified penicillin allergy and considerably lower than this among patients with an unverified penicillin allergy. Guidelines support the routine use of cephalosporins without testing or additional precautions in patients with an unverified nonanaphylactic penicillin allergy and the routine use of structurally dissimilar cephalosporins (specifically Ancef) even in patients with an anaphylactic penicillin allergy. In cases in which there is no appropriate alternative antibiotic than that for which the patient is allergic, such as syphilis in a pregnant patient with penicillin allergy, desensitization can be performed. This process involves temporary induction of drug tolerance through exposure to small amounts of the allergen until a therapeutic dose is achieved and has been safely performed in pregnancy. Desensitization requires expert supervision and is most often performed in the intensive care setting with a multidisciplinary team. The other 2 most common antibiotic allergies encountered in the field of obstetrics and gynecology are cephalosporin and metronidazole allergies. Cephalosporin allergies are managed similarly to penicillin allergies with readily available skin testing and oral challenge. Skin testing for metronidazole allergy lacks sensitivity and specificity, and thus, oral challenge or desensitization procedure is the preferred approach for low-risk and high-risk patients, respectively. When it comes to drug allergies, specifically antibiotic allergies, the role of the obstetrician-gynecologist is to identify patients with reported allergies and to refer patients to a specialist for further evaluation as soon as possible. Allergy evaluation using a detailed patient history and allergy testing (skin testing and/or oral challenge) when indicated has been shown to be safe and effective and is an important part of antibiotic stewardship.

Patterns of antimicrobial use among hospitalized Veterans with and without a penicillin-class allergy

Objective

To explore the progress that the Veterans Health Administration has made to minimize the impact of the penicillin (PCN) allergy label, we determined the proportion of Veterans who reported a PCN-class allergy at the time of hospitalization and described antibiotic use in hospitalizations with and without a PCN-class allergy.

Design

Cross-sectional study.

Participants

National sample of 6,541,299 acute care admissions between 2011 and 2022.

Methods

We calculated the prevalence of PCN-class allergies on admission and used Poisson regression to compare patterns of antibiotic use between hospitalizations with and without a PCN-class allergy.

Results

The prevalence of PCN-class allergies on admission decreased from 12.99% to 11.20%. Use of cefazolin and non-pseudomonal third-generation cephalosporins increased regardless of PCN-class allergy status ("PCN-class allergy only" +11.46%, "No antibiotic allergy" +4.92%). The prevalence ratio (PR) for antibiotic use in hospitalizations with a PCN-class allergy compared to hospitalizations without antibiotic allergies, decreased for anti-Methicillin Resistant Staphylococcus aureus agents (1.26 [1.25, 1.28] to 1.15 [1.13, 1.17]), carbapenems (1.59 [1.54, 1.65] to 1.47 [1.41, 1.53]), and aztreonam (23.89 [22.45, 25.43] to 17.57 [15.90, 19.42]); and increased for fluoroquinolones (1.58 [1.56, 1.60] to 2.15 [2.09, 2.20]).

Conclusions

Prevalence of PCN-class allergies is declining and narrow-spectrum βL use is rising among hospitalized Veterans. Prescribing differences are decreasing between hospitalizations with and without a reported PCN-class allergy, except for aminoglycosides, clindamycin, and fluoroquinolones. These findings can serve to identify areas of focus for future analyses or interventions related to the impact of the PCN allergy label on antibiotic selection.

Prolonged versus single dose in penicillin oral challenge testing: protocols for a pilot and definitive randomised controlled trial (PROSPECTOR studies)

INTRODUCTION

Penicillin allergy labels (PALs) are reported in 1 in 10 hospitalised patients globally and associated with inferior patient, hospital and microbiological outcomes; however, the majority are incorrect and should be removed. Direct oral penicillin challenge has been demonstrated to be a safe and effective method for the removal of PALs. However, the question of whether a single dose is sufficient to ascertain true allergy status remains unanswered, with some studies suggesting that extended challenges of 3 or more days are superior for the exclusion of delayed immune reactions. The aim of the PROSPECTOR studies was to determine the feasibility (PROSPECTOR-1) of a definitive trial (PROSPECTOR-2) to evaluate the safety and effectiveness of prolonged oral challenge (ie, 5 days) versus single-dose oral challenge in patients with a delayed or unknown penicillin allergy phenotype (PROSPECTOR-2).

METHODS AND ANALYSIS

A pair of double-blind two-arm parallel placebo-controlled trials will be undertaken-PROlonged versus Single dose in PEnicillin oral Challenge Testing double-blind parallel group randomised placebo-cOntrolled tRial (PROSPECTOR Studies). Patients with a reported delayed or unknown timing penicillin allergy who have passed a supervised single-dose oral amoxicillin challenge (with or without prior skin testing/single or split dose) will be recruited. Informed patient consent will be granted for sites to recruit patients and collect routine clinical data. PROSPECTOR-1 will assess the safety and feasibility of a placebo-controlled trial for single-dose amoxicillin challenge versus 5-day prolonged oral challenge. PROSPECTOR-2 will assess the superiority of the 5-day prolonged oral challenge compared with single-dose amoxicillin challenge in excluding a delayed immune reaction. PROSPECTOR-2 will commence immediately post completion of PROSPECTOR-1 in a vanguard design, with adjustments to the projected sample size for superiority made following completion of PROSPECTOR-1. PROSPECTOR-2 will commence recruitment immediately following closure of PROSPECTOR-1; however, data from each trial will be analysed separately.

ETHICS AND DISSEMINATION

These studies were reviewed and approved by the Austin Health Human Research Ethics Committee (PROSPECTOR-1: HREC/99740/Austin-2023 and PROSPECTOR-2: HREC/109785/Austin-2024). The results will be published in peer-reviewed journals and presented at relevant conferences.

TRIAL REGISTRATION NUMBER

PROSPECTOR-1: ACTRN12623001242617 and PROSPECTOR-2: ACTRN12624001107516.

Improving cefazolin administration for surgical prophylaxis in reported penicillin allergy: A retrospective study of a health system intervention

Background

Cefazolin is the most common first-line antibiotic to prevent surgical-site infections. Patients with penicillin allergy labels often receive alternative antibiotics, which is associated with increased rates of surgical-site infections, multi-drug-resistant infections, and cost.

Objective

We sought to determine whether a hospital-wide guideline recommending first-line surgical prophylaxis in patients with penicillin allergy labels can increase the use of cefazolin without compromising safety.

Methods

We conducted a retrospective cohort study of adult surgical patients with penicillin allergy labels. The main intervention was updated hospital-wide surgical guidelines recommending first-line prophylaxis in most patients with penicillin allergy labels. We compared the preintervention and postintervention groups. The primary outcome was cefazolin use. Secondary perioperative outcomes included alternative antibiotic use and severe allergic episodes (anaphylaxis).

Results

The total sample comprised 7187 patients with penicillin allergy labels who underwent 8945 surgical encounters (median age [interquartile range], 61 [46-71] years); 4891 [68%] female). Cefazolin was used in 2256 (73%) patients in the preintervention group and 3390 (83%) patients in the postintervention group (P < .001), with an adjusted odds ratio of 1.87 (95% CI, 1.67-2.10). There was a decrease in the use of clindamycin from 14% to 8% (P < .001) and gentamicin from 16% to 8% (P < .001). There were no episodes of severe allergic reactions among patients who received guideline-directed therapy.

Conclusions

A hospital-wide guideline can improve use of cefazolin in surgical patients with penicillin allergy labels without increasing the risk for severe allergic reactions. National and international guidance should be considered to enhance administration of cefazolin in surgical patients with penicillin allergy labels.

Stability of Antibiotics for Use in the Testing of Immediate Drug Allergy Reactions

BACKGROUND

Limited information is available regarding the physicochemical stability of penicillin-based preparations for skin testing purposes, and no information is currently available for other classes of antibiotics.

OBJECTIVE

To perform chemical and physical stability studies on 16 parenteral antibiotics for skin testing purposes, with an overall aim to provide practical recommendations to clinicians on suitable components, storage, and optimal shelf-life of such preparations.

METHODS

Chemical stability was assessed via validated stability-indicating high performance liquid chromatography with ultraviolet detection assays, while absence of precipitations or haziness, significant pH shift, and color change were used to determine physical stability.

RESULTS

Other than amoxicillin/clavulanic acid, all of the parenteral antibiotics were found to have adequate physicochemical stability between 2 and 7 days. Amoxicillin in water for injection BP retained more than 90% stability, whereas amoxicillin/clavulanic acid dropped to less than 80%. Ampicillin remained more than 90% stable for 2 days, and benzylpenicillin, flucloxacillin, and piperacillin/tazobactam were stable for 2 days or more at approximately 95%. Cephalosporins were stable for 2 days, except ceftazidime, which increased to more than 110%. Aztreonam, ciprofloxacin, and vancomycin retained more than 95% stability for 7 days, whereas meropenem was stable for 2 days. Sulfamethoxazole/trimethoprim in plastic syringe lost 15% but stabilized at approximately 85% for 7 days. No precipitation occurred, but amoxicillin/clavulanic acid changed color by day 2. pH decreases of 1.0 unit or less were observed in penicillins, whereas cefepime dropped below acceptable pH limits by day 7. Absorbance shifts of more than 100 units were seen in several antibiotics by day 7.

CONCLUSIONS

This study has generated practical stability information for clinicians, allowing 15 parenteral antibiotics from 7 different classes to be aseptically prepared in advance for use in the testing of drug allergy reactions.

Aspirin hypersensitivity diagnostic index (AHDI): In vitro test for diagnosing of N-ERD based on urinary 15-oxo-ETE and LTE4 excretion

BACKGROUND

15-oxo-eicosatetraenoic acid (15-oxo-ETE), is a product of arachidonic acid (AA) metabolism in the 15-lipoxygenase-1 (15-LOX-1) pathway. 15-oxo-ETE was overproduced in the nasal polyps of patients with nonsteroidal anti-inflammatory drug-exacerbated respiratory disease (N-ERD). In this study we investigated the systemic biosynthesis of 15-oxo-ETE and leukotriene E4 (LTE4) and assessed their diagnostic value to identify patients with N-ERD.

METHODS

The study included 64 patients with N-ERD, 59 asthmatics who tolerated aspirin well (ATA), and 51 healthy controls. A thorough clinical characteristics of asthmatics included computed tomography of paranasal sinuses. Plasma and urinary 15-oxo-ETE levels, and urinary LTE4 excretion were measured using high-performance liquid chromatography and tandem mass spectrometry. Repeatability and precision of the measurements were tested.

RESULTS

Plasma 15-oxo-ETE levels were the highest in N-ERD (p < .001). A receiver operator characteristic (ROC) revealed that 15-oxo-ETE had certain sensitivity (64.06% in plasma, or 88.24% in urine) for N-ERD discrimination, while the specificity was rather limited. Modeling of variables allowed to construct the Aspirin Hypersensitivity Diagnostic Index (AHDI) based on urinary LTE4-to-15-oxo-ETE excretion corrected for sex and the Lund-Mackay score of chronic rhinosinusitis. AHDI outperformed single measurements in discrimination of N-ERD among asthmatics with an area under ROC curve of 0.889, sensitivity of 81.97%, specificity of 87.23%, and accuracy of 86.87%.

CONCLUSIONS

We confirmed 15-oxo-ETE as a second to cysteinyl leukotrienes biomarker of N-ERD. An index based on these eicosanoids corrected for sex and Lund-Mackay score has a similar diagnostic value as gold standard oral aspirin challenge in the studied group of patients with asthma.

Anaphylaxis to Oral Trimethoprim-Sulfamethoxazole in a Child: A Case Report

Trimethoprim-sulfamethoxazole (TMP-SMX) is a non-β-lactam antibiotic commonly used in pediatrics to treat infections and as a prophylactic medication. Hypersensitivity to TMP-SMX is generally non-immediate, and immediate allergic reactions, including anaphylaxis, are rare. This case report details a six-year-old girl who experienced anaphylaxis to TMP-SMX. Her skin prick test with TMP-SMX was negative, but she developed anaphylaxis in a drug provocation test (DPT). An additional basophil activation test (BAT) for the TMP-SMX combination tablet was evaluated and was confirmed positive. This case underscores the need for alternative diagnostic methods like BAT, which pose a lower risk than DPT. The findings suggest that BAT could offer a safer diagnostic approach, though more studies are required to validate its use for TMP-SMX allergy diagnosis.

Drug allergy

Drug allergy encompasses a spectrum of immunologically-mediated hypersensitivity reactions (HSRs) with varying mechanisms and clinical presentations. This type of adverse drug reaction (ADR) not only affects patient quality of life, but may also lead to delayed treatment, unnecessary investigations, and increased morbidity and mortality. Given the spectrum of symptoms associated with the condition, diagnosis can be challenging. Therefore, referral to an allergist experienced in the diagnosis and management of drug allergy is recommended if a drug-induced allergic reaction is suspected. Diagnosis relies on a careful history and physical examination and, in some instances, skin testing or in vitro testing and drug challenges. The most effective strategy for the management of allergist-confirmed drug allergy is avoidance or discontinuation of the offending drug. When available, alternative medications with unrelated chemical structures should be substituted. Cross-reactivity among drugs should also be taken into consideration when choosing alternative agents. Additional therapy for drug HSRs may include topical corticosteroids, oral antihistamines and, in severe cases, systemic corticosteroids and other immunomodulators. In the event of anaphylaxis, the treatment of choice is intramuscular epinephrine. If a patient with a history of anaphylaxis requires a specific drug and there is no acceptable alternative, desensitization to that drug may be considered. This article provides a background on drug allergy and strategies for the diagnosis and management of some of the most common drug-induced allergic reactions.