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

Early testing and grade of the reaction are affecting factors of skin test positivity in β-Lactam allergies

Background: β-Lactams are the most widely used antibiotic family in the world. Nevertheless, they also stand out as the primary culprits for inducing drug hypersensitivity reactions (HSR). Methods: Between May 2018 and March 2023, patients with suspected HSRs to β-lactams, who underwent skin tests (ST), were retrospectively screened. The determinants of allergenic penicillin (DAP) tests, which include penicillin minor and major determinants, clavulanic acid, and amoxicillin, along with ampicillin, sulbactam, the identified culprit drugs, and alternative cephalosporins, which include cefuroxime, ceftriaxone prick and/or intradermal tests, were administered. The analysis focused on identifying positive ST results and determining the true HSRs rates in this patient cohort. Results: Of the 147 patients, 78.9% (n = 116) were women and the median (minimum-maximum) age was 41 years (18-71 years). Mild HSRs (grades 1-2) were observed in 72.78% (n = 107), whereas 24.4% (n = 36) had severe reactions (grades 3-4) and 2.7% (n = 4) had an unknown grade. Of the patients, 64% (n = 94) experienced HSRs within the first hour after the last dose of the identified culprit drug. The overall positivity rate for all STs was 26.5% (n = 39). ST positivity rates were notably higher in individuals who had experienced HSRs within the past 6 months (p = 0.02) and those with severe anaphylaxis (p < 0.001). Conclusion: β-Lactam ST positivity is higher, especially in those with grades 3-4 reactions and consulted a physician within the first 6 months after their HSRs.

[Penicillin allergy: A label that is not forever]

Self-reported penicillin allergy is highly prevalent. Different studies estimate that 10% of the population is labeled as such. This label, confirmed or suspected, forces us to take precautions and replace the antibiotic treatment of choice (frequently beta-lactams) with other 2nd or 3rd choice alternatives with worse overall results: side effects, resistance, costs, etc. The penicillin allergy label, once placed, remains in the medical record. It is only confirmed in less than 5% of patients, either because it has been placed inappropriately or because over time the sensitivity decreases and may disappear. Penicillin Allergy Decision Rule -PEN-FAST- is a validated and simple clinical prediction rule that estimates the risk of presenting an allergic reaction. Its use, together with algorithms that involve primary care in the study and delabeling of low-risk patients, can change our clinical practice.

Candent issues in pneumonia. Reflections from the Fifth Annual Meeting of Spanish Experts 2023

Pneumonia is a multifaceted illness with a wide range of clinical manifestations, degree of severity and multiple potential causing microorganisms. Despite the intensive research of recent decades, community-acquired pneumonia remains the third-highest cause of mortality in developed countries and the first due to infections; and hospital-acquired pneumonia is the main cause of death from nosocomial infection in critically ill patients. Guidelines for management of this disease are available world wide, but there are questions which generate controversy, and the latest advances make it difficult to stay them up to date. A multidisciplinary approach can overcome these limitations and can also aid to improve clinical results. Spanish medical societies involved in diagnosis and treatment of pneumonia have made a collaborative effort to actualize and integrate last expertise about this infection. The aim of this paper is to reflect this knowledge, communicated in Fifth Pneumonia Day in Spain. It reviews the most important questions about this disorder, such as microbiological diagnosis, advances in antibiotic and sequential therapy, management of beta-lactam allergic patient, preventive measures, management of unusual or multi-resistant microorganisms and adjuvant or advanced therapies in Intensive Care Unit.

Delabeling of allergy to beta-lactam antibiotics in hospitalized patients: a prospective study evaluating cost savings

BACKGROUND

Patients with a penicillin allergy label are at risk of an associated increase in adverse antibiotic events and hospitalization costs.

AIM

We aimed to study the economic savings derived from the correct diagnosis and delabeling inpatients with suspected beta-lactam allergy, considering the acquisition cost of antimicrobials prescribed during a patient's hospital stay.

METHOD

We prospectively evaluated patients admitted to the University Hospital of Salamanca who had been labeled as allergic to beta-lactams and performed a delabeling study. Subsequently, cost differences between antibiotics administered before and after the allergy study and those derived from those patients who received alternative antibiotics during admission and those who switched to beta-lactams after the allergy study were calculated.

RESULTS

One hundred seventy-seven inpatients labeled as allergic to beta-lactams underwent a delabeling study; 34 (19.2%) were confirmed to have allergy to beta-lactams. Of the total number of patients, 136 (76.8%) received antibiotics during their hospitalization, involving a mean (SD) cost of €203.07 (318.42) and a median (IQR) cost of €88.97 (48.86-233.56). After delabeling in 85 (62.5%) patients, the antibiotic treatment was changed to beta-lactams. In this group of patients, the mean cost (SD) decreased from €188.91 (351.09) before the change to 91.31 (136.07) afterward, and the median cost (IQR) decreased from €72.92 (45.82-211.99) to €19.24 (11.66-168). The reduction was significant compared to the median cost of patients whose treatment was not changed to beta-lactams (p<0.001).

CONCLUSION

Delabeling hospitalized patients represents a cost-saving measure for treating patients labeled as allergic to beta-lactams.

Qualitative analysis of healthcare provider perspectives to evaluating beta-lactam allergies

BACKGROUND

There is a lack of understanding of the barriers reported by healthcare providers when evaluating beta-lactam allergies, but knowledge of these barriers is required for practical and effective implementation interventions.

METHODS

Twenty-five healthcare providers, consisting of physicians, nurses and pharmacists practicing in the areas of intensive care, emergency medicine, infectious disease and general hospital practice, were interviewed between September 2021 and July 2023. Twenty-three of these providers were practising in the USA. A semi-structured interview guide grounded in the Theoretical Domain Framework was used for the interviews. Deductive and inductive analysis was performed on the interview transcripts, and translated into intervention recommendations using the Behaviour Change Wheel.

RESULTS

Widely held beliefs included a lack of clear policy for the evaluation of allergies, confusing or missing documentation of allergy information, confidence in their own and their colleagues' ability to evaluate allergies when information is available, and pharmacists as the provider most equipped to evaluate beta-lactam allergies.

CONCLUSIONS

Health systems should adopt and disseminate policies for the evaluation of beta-lactam allergies, and promote the use of pharmacists in the evaluation of drug allergies when possible. Allergy sections of electronic health records should be reworked to encourage unambiguous documentation of allergy reactions and support using previously tolerated beta-lactam antibiotics.

Guideline for allergological diagnosis of drug hypersensitivity reactions: S2k Guideline of the German Society for Allergology and Clinical Immunology (DGAKI) in cooperation with the German Dermatological Society (DDG), the Association of German Allergologists (ÄDA), the German Society for Pediatric Allergology (GPA), the German Contact Dermatitis Research Group (DKG), the German Society for Pneumology (DGP), the German Society of Otorhinolaryngology, Head and Neck Surgery, the Austrian Society of Allergology and Immunology (ÖGAI), the Austrian Society of Dermatology and Venereology (ÖGDV), the German Academy of Allergology and Environmental Medicine (DAAU), and the German Documentation Center for Severe Skin Reactions (dZh)

Not available.

Viral infections and drug hypersensitivity

Virus infections and T-cell-mediated drug hypersensitivity reactions (DHR) can influence each other. In most instances, systemic virus infections appear first. They may prime the reactivity to drugs in two ways: First, by virus-induced second signals: certain drugs like β-lactam antibiotics are haptens and covalently bind to various soluble and tissue proteins, thereby forming novel antigens. Under homeostatic conditions, these neo-antigens do not induce an immune reaction, probably because co-stimulation is missing. During a virus infection, the hapten-modified peptides are presented in an immune-stimulatory environment with co-stimulation. A drug-specific immune reaction may develop and manifest as exanthema. Second, by increased pharmacological interactions with immune receptors (p-i): drugs tend to bind to proteins and may even bind to immune receptors. Without viral infections, this low affine binding may be insufficient to elicit T-cell activation. During a viral infection, immune receptors are more abundantly expressed and allow more interactions to occur. This increases the overall avidity of p-i reactions and may even be sufficient for T-cell activation and symptoms. There is a situation where the virus-DHR sequence of events is inversed: in drug reaction with eosinophilia and systemic symptoms (DRESS), a severe DHR can precede reactivation and viremia of various herpes viruses. One could explain this phenomenon by the massive p-i mediated immune stimulation during acute DRESS, which coincidentally activates many herpes virus-specific T cells. Through p-i stimulation, they develop a cytotoxic activity by killing herpes peptide-expressing cells and releasing herpes viruses. These concepts could explain the often transient nature of DHR occurring during viral infections and the often asymptomatic herpes-virus viraemia after DRESS.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Individualized surgical antibiotic prophylaxis – why, when, and how?

"Surgical site infections (SSI) greatly concern clinicians, as they are associated with significant morbidity and mortality, prolonged hospitalization, and costs. Antibiotic prophylaxis plays a pivotal role among the procedures that are usually employed for the prevention of surgical-related infections. This narrative review aims to cover some of the particular situations when the clinician might consider individualizing antibiotic prophylaxis for a patient. With the rising incidence of multi-drug resistant bacteria carriage among not only hospitalized or institutionalized patients but also patients from the community, there might be a tendency to use extended-spectrum antibiotics for longer periods for surgical infection prevention. However, the inappropriate use of antibiotics increases the selection pressure, thus favoring the spreading of resistant bacteria. Moreover, specific patient characteristics or pathologies might need to be considered to customize the type, dose, or length of administration of an antibiotic as surgical prophylaxis. Using prosthetic material or prolonged surgeries with large fluid shifts are other situations when individualized antibiotic prophylaxis might be thought of. Keeping in mind that it is of utmost importance that everyone adheres to the current guidelines for surgical antibiotic prophylaxis, customization of local protocols according to well-thought-out strategies might prove beneficial in SSI prevention."

Changes in Sensitization Patterns in the Last 25 Years in 619 Patients with Confirmed Diagnoses of Immediate Hypersensitivity Reactions to Beta-Lactams

Beta-lactam (BL) drugs are the antibiotics most prescribed worldwide due to their broad spectrum of action. They are also the most frequently implied in hypersensitivity reactions with a known specific immunological mechanism. Since the commercialization of benzylpenicillin, allergic reactions have been described; over the years, other new BL drugs provided alternative treatments to penicillin, and amoxicillin is now the most prescribed BL in Europe. Diagnosis of BL allergy is mainly based on skin tests and drug provocation tests, defining different sensitization patterns or phenotypes. In this study, we evaluated 619 patients with a confirmed diagnosis of BL-immediate allergy during the last 25 years, using the same diagnostic procedures with minor adaptations to the successive guidelines. The initial eliciting drug was benzylpenicillin, which changed to amoxicillin with or without clavulanic acid and cephalosporins in recent years. In skin tests, we found a decrease in sensitivity to major and minor penicillin determinants and an increase in sensitivity to amoxicillin and others; this might reflect that the changes in prescription could have influenced the sensitization patterns, thus increasing the incidence of specific reactions to side-chain selective reactions.