A call to address penicillin allergy labels in patients with hematopoietic stem cell transplants: How to avoid rash decisions.

Among patients with hematopoietic stem cell transplants, infections, particularly multidrug-resistant infections, pose a grave threat. In this setting, penicillin allergy labels are both common and harmful. Though the majority of patients who report penicillin allergy can actually tolerate penicillin, penicillin allergy labels are associated with use of alternative antibiotics, which are often more broad spectrum, less effective, and more toxic. In turn, they are associated with more severe infections, multidrug-resistant infections, Clostridium difficile, and increased mortality. Evaluating penicillin allergy labels can immediately expand access to preferred therapeutic options, which are critical to care in patients with recent hematopoietic stem cell transplants. Point-of-care assessment and clinical decision tools now exist to aid the nonallergist in assessment of penicillin allergy. This can aid in expanding use of other beta-lactam antibiotics and assist in risk-stratifying patients to determine a testing strategy. In patients with low-risk reaction histories, direct oral challenges can be employed to efficiently delabel patients across clinical care settings. We advocate for multidisciplinary efforts to evaluate patients with penicillin allergy labels prior to transplantation.

Risk of Self-Reported Penicillin Allergy Despite Removal of Penicillin Allergy Label: Secondary Analysis of the PALACE Randomized Clinical Trial.

This secondary analysis of adult patients in the Penicillin Allergy Clinical Decision Rule (PALACE) Study investigates the risk of self-reported penicillin allergy despite removal of penicillin allergy label.

Effectiveness of direct delabelling of allergy labels in type A adverse drug reactions to penicillin: a multicentre hospitalwide prospective cohort study.

BACKGROUND: Patient-reported penicillin allergy labels (PALs) are associated with adverse patient outcomes and inappropriate antibiotic prescribing. Removal of PALs via direct oral challenge (DOC) is associated with increased penicillin utilization post removal. OBJECTIVES: To assess the impact of direct delabelling (allergy label removal via medical reconciliation alone) of type A adverse drug reaction (ADR) PALs on inpatient prescribing. METHODS: From January 2019 to December 2022 at two tertiary hospitals in Melbourne, patients aged ≥18 years with type A ADR PALs, as defined by the validated Antibiotic Allergy Assessment Tool, were offered direct delabelling or single-dose DOC. The primary endpoint was antibiotic use pre- and post-assessment (during index admission and 90 days post assessment). The secondary endpoint was the proportion of patients delabelled in the direct delabelling and DOC cohorts in the electronic medical record at 90 days post assessment. RESULTS: Allergy labels (n = 4108) were assessed for 488 participants, with 490 individual type A ADR PAL assessments included. Three hundred and thirty-seven patients were directly delabelled, 69 underwent DOC and 84 were not delabelled. There was increased use of any penicillin following direct delabelling (OR 19.19, 95% CI 2.48-148.36) and DOC (OR 56.98, 95% CI 6.82-476.19) during the index admission, higher in the DOC group compared with direct delabelling (OR 2.97, 95% CI 1.39-6.37). Relabelling at 90 days was low with no statistically significant difference between direct delabelling (5/337; 1.5%) and DOC (0/69; 0%). CONCLUSIONS: Both direct delabelling and DOC of type A ADR PALs increased penicillin usage; however, the impact was greatest with DOC. Most patients remain delabelled at 90 days.

Oral challenge vs routine care to assess low-risk penicillin allergy in critically ill hospital patients (ORACLE): a pilot safety and feasibility randomised controlled trial.

PURPOSE: Critically ill patients are vulnerable to penicillin allergy labels that may be incorrect. The validity of skin testing in intensive care units (ICUs) is uncertain. Many penicillin allergy labels are low risk, and validated tools exist to identify those amenable to direct oral challenge. This pilot randomised controlled trial explored the feasibility, safety, and validity of direct enteral challenge for low-risk penicillin allergy labels in critical illness. METHODS: Consenting patients with a low-risk penicillin allergy label (PAL) (PEN-FAST risk assessment score < 3) in four ICUs (Melbourne, Australia) were randomised 1:1 to penicillin (250 mg amoxicillin or implicated penicillin) direct enteral challenge versus routine care (2-h post-randomisation observation for each arm). Repeat challenge was performed post -ICU in the intervention arm. Patients were reviewed at 24 h and 5 days after each challenge/observation. RESULTS: We screened 533 patients. 130 (24.4%) were eligible and 80/130 (61.5%) enrolled (age median 64.5 years (interquartile range, IQR 53.5, 74), PEN-FAST median 1 (IQR 0,1)), with 40 (50%) randomised to direct enteral challenge. A positive challenge rate of 2.5% was identified. No antibiotic-associated serious adverse events were identified. 32/40 (80%) received a repeat challenge (zero positive). Post-randomisation, 13 (32%) of the intervention arm and 4 (10%) of the control arm received penicillin (odds ratio, OR 4.33 [1.27, 14.78] p = 0.019). CONCLUSION: These findings support the safety, validity, and feasibility of direct enteral challenge for critically ill patients with PEN-FAST assessed low-risk penicillin allergy. The absence of false negative results was confirmed by subsequent negative repeat challenges. A relatively low recruitment to screened ratio suggests that more inclusive eligibility criteria and integration of allergy assessment into routine ICU processes are needed to optimise allergy delabelling in critical illness.

How to Define and Manage Low-Risk Drug Allergy Labels.

Risk stratification in drug allergy implies that specific risk categories (eg, low, moderate, and high) classify historical drug hypersensitivity reactions. These risk categories can be based on reaction phenotypic characteristics, the timing of the reaction and evaluation, the required reaction management, and individual characteristics. Although a multitude of frameworks have been described in the literature, particularly for penicillin allergy labels, there has yet to be a global consensus, and approaches continue to vary between allergy centers. Immune-mediated drug allergies can sometimes be confirmed using skin testing, but a negative drug challenge is required to demonstrate tolerance and remove the allergy from the electronic health record ("delabel" the allergy). Even for quintessential IgE-mediated drug allergy, penicillin allergy, recent data reveal that a direct oral challenge, without prior skin testing, is an appropriate diagnostic strategy in those who are considered low-risk. Drug allergy pathogenesis and clinical manifestations may vary depending on the culprit drug, and as such, the optimal approach should be based on risk stratification that considers individual patient and reaction characteristics, the likely hypersensitivity reaction phenotype, the drug class, and the patient's clinical needs. This article will describe low-risk drug allergy labels, focusing on ß-lactam and sulfonamide antibiotics, nonsteroidal anti-inflammatory drugs, iodinated contrast media, and common chemotherapeutics. This review will also address practical management approaches using currently available risk stratification and clinical decision tools.

Immunoglobulin G genetic variation can confound assessment of antibody levels via altered binding to detection reagents.

Objectives: Amino acid variations across more than 30 immunoglobulin (Ig) allotypes may introduce structural changes that influence recognition by anti-Ig detection reagents, consequently confounding interpretation of antibody responses, particularly in genetically diverse cohorts. Here, we assessed a panel of commercial monoclonal anti-IgG1 clones for capacity to universally recognise two dominant IgG1 haplotypes (G1m-1,3 and G1m1,17). Methods: Four commercial monoclonal anti-human IgG1 clones were assessed via ELISAs and multiplex bead-based assays for their ability to bind G1m-1,3 and G1m1,17 IgG1 variants. Detection antibodies were validated against monoclonal IgG1 allotype standards and tested for capacity to recognise antigen-specific plasma IgG1 from G1m-1,3 and G1m1,17 homozygous and heterozygous SARS-CoV-2 BNT162b2 vaccinated (n = 28) and COVID-19 convalescent (n = 44) individuals. An Fc-specific pan-IgG detection antibody corroborated differences between hinge- and Fc-specific anti-IgG1 responses. Results: Hinge-specific anti-IgG1 clone 4E3 preferentially bound G1m1,17 compared to G1m-1,3 IgG1. Consequently, SARS-CoV-2 Spike-specific IgG1 levels detected in G1m1,17/G1m1,17 BNT162b2 vaccinees appeared 9- to 17-fold higher than in G1m-1,3/G1m-1,3 vaccinees. Fc-specific IgG1 and pan-IgG detection antibodies equivalently bound G1m-1,3 and G1m1,17 IgG1 variants, and detected comparable Spike-specific IgG1 levels between haplotypes. IgG1 responses against other human coronaviruses and influenza were similarly poorly detected by 4E3 anti-IgG1 in G1m-1,3/G1m-1,3 subjects. Conclusion: Anti-IgG1 clone 4E3 confounds assessment of antibody responses in clinical cohorts owing to bias towards detection of G1m1,17 IgG1 variants. Validation of anti-Ig clones should include evaluation of binding to relevant antibody variants, particularly as the role of immunogenetics upon humoral immunity is increasingly explored in diverse populations.

Costs associated with invasive Scedosporium and Lomentospora prolificans infections: a case-control study.

BACKGROUND: Little is known about the short- and long-term healthcare costs of invasive Scedosporium/Lomentospora prolificans infections, particularly in patient groups without haematological malignancy. This study investigated excess index hospitalization costs and cumulative costs of these infections. The predictors of excess cost and length of stay (LOS) of index hospitalization were determined. These estimates serve as valuable inputs for cost-effectiveness models of novel antifungal agents. METHODS: A retrospective case-control study was conducted at six Australian hospitals. Cases of proven/probable invasive Scedosporium/L. prolificans infections between 2011 and 2021 (n = 34) were matched with controls (n = 66) by predefined criteria. Cost data were retrieved from activity-based costing systems and analysis was performed from the Australian public hospital perspective. All costs were presented in 2022 Australian dollars (AUD). Median regression analysis was used to adjust excess costs of index hospitalization whereas cumulative costs up to 1.5 years follow-up were estimated using interval-partitioned survival probabilities. RESULTS: Invasive Scedosporium/L. prolificans infections were independently associated with an adjusted median excess cost of AUD36 422 (P = 0.003) and LOS of 16.27 days (P < 0.001) during index hospitalization. Inpatient stay was the major cost driver (42.7%), followed by pharmacy cost, of which antifungal agents comprised 23.8% of the total cost. Allogeneic haematopoietic stem cell transplant increased the excess cost (P = 0.013) and prolonged LOS (P < 0.001) whereas inpatient death within ≤28 days reduced both cost (P = 0.001) and LOS (P < 0.001). The median cumulative cost increased substantially to AUD203 292 over 1.5 years in cases with Scedosporium/L. prolificans infections. CONCLUSIONS: The economic burden associated with invasive Scedosporium/L. prolificans infections is substantial.

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.

Drug Allergy in Women.

Across all settings, women self-report more drug allergies than do men. Although there is epidemiologic evidence of increased drug allergy labeling in postpubertal females, the evidence base for female sex as a risk factor for true immune-mediated drug hypersensitivity reactions (DHRs), particularly in fatal drug-induced anaphylaxis, is low. A focus on the known immunologic mechanisms described in immediate and delayed DHR, layered on known hormonal and genetic sex differences that drive other immune-mediated diseases, could be the key to understanding biological sex variations in DHR. Particular conditions that highlight the impact of drug allergy in women include (1) pregnancy, in which a drug allergy label is associated with increased maternal and fetal complications; (2) multiple drug intolerance syndrome, associated with anxiety and depression; and (3) female-predominant autoimmune medical conditions in the context of mislabeling of the drug allergy or increased underlying risk. In this review, we describe the importance of drug allergy in the female population, mainly focusing on the epidemiology and risk, the mechanisms, and the associated conditions and psychosocial factors. By performing a detailed analysis of the current literature, we provide focused conclusions and identify existing knowledge gaps that should be prioritized for future research.

Improving the management of medical emergency team calls due to suspected infections: A before-after study.

Objective: To introduce a management guideline for sepsis-related MET calls to increase lactate and blood culture acquisition, as well as prescription of appropriate antibiotics. Design: Prospective before (Jun-Aug 2018) and after (Oct-Dec 2018) study was designed. Setting: A public university linked hospital in Melbourne, Australia. Participants: Adult patients with MET calls related to sepsis/infection were included. Main outcome measures: The primary outcome measure was the proportion of MET calls during which both a blood culture and lactate level were ordered. Secondary outcomes included the frequency with which new antimicrobials were commenced by the MET, and the presence and class of administered antimicrobials. Results: There were 985 and 955 MET calls in the baseline and after periods, respectively. Patient features, MET triggers, limitations of treatment and disposition after the MET call were similar in both groups. Compliance with the acquisition of lactates (p = 0.101), respectively. There was a slight reduction in compliance with lactate acquisition in the after period (97% vs 99%; p = 0.06). In contrast, there was a significant increase in acquisition of blood cultures in the after period (69% vs 78%; p = 0.035). Conclusions: Introducing a sepsis management guideline and enhanced linkage with an AMS program increased blood culture acquisition and decreased broad spectrum antimicrobial use but didn't change in-hospital mortality.

Invasive fungal infection following venetoclax and posaconazole co-administration.

The co-administration of venetoclax, a BCL-2 inhibitor, with a mould-active azole, such a posaconazole, has potential to both prevent invasive fungal infection (IFI) and reduce the required treatment dose, and cost, of venetoclax. Posaconazole drug-level monitoring is critical to ensuring adequate mould prophylaxis. A retrospective audit of 99 patients at a tertiary cancer centre, with myeloid malignancies co-prescribed venetoclax and posaconazole between January 2018 and April 2022, was undertaken to evaluate the adequacy of posaconazole prescribing and the rate of breakthrough IFI. Seventy-six patients (77%) had at least one posaconazole level measured in the study period, with 37% requiring a dose adjustment based on steady-state trough levels. Breakthrough IFI occurred in 4% of patients, typically within 1 month of commencing anti-mould prophylaxis. Close monitoring of posaconazole levels in venetoclax-treated patients, particularly in the early, outpatient setting, is critical.

Penicillin Allergy Impact and Management.

There is international evidence that penicillin allergies are associated with inferior prescribing and patient outcomes. A host of tools now exist from assessment (risk assessment tools, clinical decision rules) to delabeling (the removal of a beta-lactam allergy via testing or medical reconciliation) to reduce the impact of these "labels" in the hospital and community setting, as a primary antimicrobial stewardship intervention.