Guideline on diagnostic procedures for suspected hypersensitivity to beta-lactam antibiotics: Guideline of the German Society for Allergology and Clinical Immunology (DGAKI) in collaboration with the German Society of Allergology (AeDA), German Society for Pediatric Allergology and Environmental Medicine (GPA), the German Contact Dermatitis Research Group (DKG), the Austrian Society for Allergology and Immunology (ÖGAI), and the Paul-Ehrlich Society for Chemotherapy (PEG)

Recommendations on how to proceed in case of suspected allergy to penicillin/β-lactam antibiotics: Position paper of the German Society for Allergology and Clinical Immunology (DGAKI) in cooperation with the German Society for Pediatric Allergology (GPA), Austrian Society for Allergology and Immunology (ÖGAI) and the Swiss Society for Allergology and Immunology (SGAI)

β-lactam antibiotics (BLAs) are still the antibiotics of first choice for the treatment of many bacterial infections. Treatment with a BLA is often hindered by a suspected allergy, up to 10% of the population report an allergy to penicillin. After allergological evaluation of the suspected allergic reaction to a BLA, most patients show a low probability of a BLA allergy; only in a minority of cases an allergic reaction to the repeated administration of a BLA appear likely in view of the previous history. In > 90% of cases, the suspected BLA allergy can be ruled out by allergy diagnostics. We recommend a risk-stratified approach in the context of an urgent need for BLA, which should enable most patients to receive a BLA therapy. After acute therapy, allergy diagnostics have to be done to clearly prove or reliably rule out a BLA allergy.

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.

Promoting penicillin allergy de-labeling for children attending a hematology clinic

BACKGROUND

Up to 10% of children are reported to be allergic to penicillin, but many allergy labels are unverified and may require formal testing. Inaccurate drug allergy labels are associated with a range of adverse clinical outcomes. Patients with hematological disorders may experience frequent and severe infections; those who have been incorrectly labeled penicillin allergic may benefit from allergy de-labeling (ADL) efforts to facilitate access to beta-lactam antibiotics. We developed a multidisciplinary, pharmacist-driven process that enabled non-allergist trained providers to assess and de-label penicillin allergies in a pediatric hematology center.

METHODS

Volunteers, including physicians, advanced practice providers, nurses, and pharmacists, were trained in skin testing and oral challenge procedures. Patients were identified by review of electronic medical records for penicillin or penicillin-derivative allergy. Patient and family interviews were conducted in cases where a true penicillin allergy was deemed uncertain based on chart review. If allergy could not be de-labeled by chart review or interview alone, patients were offered skin and/or oral challenge testing.

RESULTS

Fifty-nine patients were initially labeled as penicillin allergic. Allergy labels of 11 (19%) were removed by chart review only, and 15 (25%) after conducting interviews. A total of two (3%) patients were ineligible due to contraindications, and five (9%) declined participation. Twenty-six patients (44%) underwent allergy testing (50% skin testing, 50% oral challenge) of which 23 (88%) were negative.

CONCLUSIONS

ADL was possible in most patients previously identified as penicillin allergic. Testing was well tolerated with no serious adverse effects.

Penicillin Allergy Testing and Delabeling for Patients Who Are Prescribed Penicillin: A Systematic Review for a World Health Organization Guideline

Secondary prevention with penicillin aims to prevent further episodes of acute rheumatic fever and subsequent development of rheumatic heart disease (RHD). Penicillin allergy, self-reported by 10% of the population, can affect secondary prevention programs. We aimed to assess the role for (i) routine penicillin allergy testing and the (ii) safety of penicillin allergy delabeling approaches in this context. We searched MEDLINE, Embase, CENTRAL, ClinicalTrials.gov, WHO ICTRP, ISRCTN, and CPCI-S to identify the relevant reports. We found 2419 records, but no studies addressed our initial question. Following advice from the WHO-Guideline committee and experts, we identified 6 manuscripts on allergy testing focusing on other populations showing that the prevalence of allergy confirmed by testing was low and the incidence of life-threatening reactions to BPG was very low (< 1-3/1000 individuals treated). A subsequent search addressed penicillin allergy delabeling. This found 516 records, and 5 studies addressing the safety of direct oral drug challenge vs. skin testing followed by drug administration in patients with suspected penicillin allergy. Immediate allergic reactions of minor severity were observed for a minority of patients and occurred less frequently in the direct drug challenge group: 2.3% vs. 11.5%; RR = 0.25, 95%CI 0.15-0.45, P < 0.00001, I2 = 0%. No anaphylaxis or deaths were observed. Severe allergic reactions to penicillin are extremely rare and can be recognized and dealt by trained healthcare workers. Confirmation of penicillin allergy diagnosis or delabeling using direct oral drug challenge or penicillin skin testing seems to be safe and is associated with a low rate of adverse reactions.

A Saudi Woman with Ceftriaxone Induced Fixed Drug Eruption

Background

A fixed drug eruption (FDE) is an immunological cutaneous adverse reaction, classified as a cutaneous adverse drug reaction (CADR) and characterized by well-defined lichenoid lesions that occur at the same site each time. Ceftriaxone is a third-generation antibiotic of cephalosporin antibiotics of the beta-lactam antibiotic family, which has typical in vitro activity against many Gram-negative aerobic bacteria. This is the first clinical case from Saudi Arabia and the fifth in the world to document a woman's experience with recurrent FDE after repeated ceftriaxone use. Case Report. A 25-year-old Saudi woman with a known case of sickle cell anemia (SCA) with a history of avascular necrosis of the right hip after replacement was hospitalized with a pain crisis triggered by an upper respiratory tract infection. The patient denied having a history of allergy previously. Due to fever, leukocytosis, and active follicular tonsillitis, ceftriaxone was started. However, a few hours later she developed lip edema and a fixed drug eruption measuring 7 × 11 cm on the left side of her back. The lesion reformed over a hyperpigmented lesion (4 × 8 cm) that the patient did not report upon initial examination. It turned out that this was due to the intravenous administration of ceftriaxone, a year ago in another hospital. An allergy to ceftriaxone was considered, and steroids and antihistamines were started. The case was labeled as ceftriaxone induced FDE.

Conclusion

Ceftriaxone induced FDE is an uncommon type of allergic reaction that has been reported infrequently. Understanding this condition and the mechanism by which FDE becomes recurrent with the same previous fixed lesion is of great importance for both academic and future research purposes.

[Practicability of the German guidelines on skin and soft tissue infections]

The guidelines on calculated parenteral initial treatment of bacterial infections in adults from 2018 were the first German language S2k guidelines for these infections. This article summarizes the experiences with respect to their practicality in the clinical routine and the resulting supplementations and comments. In view of the many different terms for soft tissue infections, the guidelines had to first establish some definitions and diagnostic criteria. Among others, the guidelines introduced the provisional term limited phlegmons (phlegmons are usually termed cellulitis in Angloamerican literature) for the frequent initially superficial soft tissue infections with Staphylococcus aureus, which do not always extend to the fascia, in order to differentiate them from erysipelas caused by Streptoccocus, which in contrast to phlegmons always respond to penicillin. The general symptoms present in erysipela are a practical differential criterion. Somewhat more complex are the definitions and recommendations for the severe forms of phlegmon, which involve the fascia and are accompanied by necrosis, so that here the practicality of the guidelines needs to prove its worth over time. The guidelines also give recommendations how to proceed in case of alleged or confirmed hypersensitivity to beta-lactam antibiotics. Currently, relevant guidelines recommend, and it is correspondingly here elaborated, that in acute cases a beta-lactam antibiotic with side chains other than those in the suspected drug may present an alternative without prior testing. Therefore, cefazolin, that does not share any side chains with other beta-lactam antibiotics, could be administered under appropriate precautionary measures. The term cellulitis is avoided in the guidelines. Since it is used frequently, and also for non-infectious dermatoses, the various meanings are discussed and distinguished from each other.

Diagnosis and selection of alternative antibiotics in beta-lactams hypersensitivity reactions: Current recommendations and challenges

Beta-lactam (BLM) antibiotics, including amino-penicillin and cephalosporins, are typically the first-choice treatment for bacterial infections. However, adverse reactions to these antibiotics are frequently reported, causing non-allergist physicians to select alternative broad-spectrum antibiotics that can have harmful consequences. Patients with unclear histories of hypersensitivity reactions to BLMs should undergo an allergy workup to establish a firm diagnosis, particularly when different drugs are prescribed simultaneously. However, finding the safest, most precise, and cost-effective methods for confirming BLMs hypersensitivity and selecting the most appropriate alternative BLM is uncertain, particularly in severe delayed reactions. This review aims to provide data and recommendations on the availability and validity of skin tests (STs), drug provocation test (DPT) protocols, based on the latest published literature and guideline. To make the process more practical, we focused on cross-reactivity between BLMs and diagnostic tests. There are two main novel aspects of this document: 1) For T-cell-mediated reactions, patient stratification into high, moderate, and low-risk groups based on the mortality and morbidity of adverse drug reactions. 2) For IgE-mediated reactions, stratification of individuals with isolated limited urticarial without anaphylaxis in a low-risk group and removal of the extensive limitation.

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.

The Dutch Working Party on Antibiotic Policy (SWAB) guideline for the approach to suspected antibiotic allergy

OBJECTIVES

Prudent handling of reported antibiotic allergy is an important aspect of antibiotic stewardship. The Dutch Working Party on Antibiotic Policy (SWAB) constituted a multidisciplinary expert committee to provide evidence-based recommendations for bedside decision making in antibiotic therapy in patients that report an antibiotic allergy.

METHODS

The guideline committee generated 12 key questions, most of which were population, intervention, comparison and outcome (PICO) questions relevant for both children and adults with suspected antibiotic allergy. For each question a systematic literature search was performed and reviewed for the best available evidence according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. Quality of evidence was graded from very low to high and recommendations were formulated in structured discussions as strong or weak.

RESULTS

Sixty recommendations were provided for suspected allergy to beta-lactam antibiotics (BLA) and non-beta-lactam antibiotics (NBLA). Due to the absence of randomized controlled trials in this field, the underlying evidence was predominantly graded as low or very low. Available data supports that a detailed allergy history should always be performed and critically appraised. When cross-allergy between BLA groups is not to be expected due to absence of molecular similarity of the side chains, the patient can be safely exposed to the alternative BLA. An exception to this rule are severe delayed type reactions, in which reexposure to a BLA should only be considered after consultation of a multidisciplinary team.

CONCLUSIONS

Accumulated scientific data now supports a more liberal approach that better balances benefits of treatment with first choice and usually smaller spectrum antibiotics with appropriate avoidance of antibiotics in case of a truly high risk of a (severe) allergic reaction. In the Netherlands, a formal guideline was developed that provides recommendations for the approach towards suspected allergy to BLA and frequently used NBLA, thereby strongly supporting antimicrobial stewardship.

Basophil Activation Test Shows Poor Sensitivity in Immediate Amoxicillin Allergy

BACKGROUND

In light of the pandemic of spurious penicillin allergy, correct diagnosis of amoxicillin (AX) allergy is of great importance. The diagnosis of immediate hypersensitivity reactions relies on skin tests and specific IgE, and although reliable, these are not absolutely predictive. Therefore, drug challenges are needed in some cases, which contain the risk of severe reactions. Safe in vitro diagnostics as an alternative for the drug challenge in the diagnostic workup of AX allergy would be more than welcome to fill this gap. In this respect, the basophil activation test (BAT) has shown potential, but its clinical reliability is doubtful.

OBJECTIVE

To investigate the reliability of the BAT to AX and determining its exact place in the diagnostic algorithm of AX allergy.

METHODS

BAT for AX was performed in 70 exposed control individuals and 66 patients diagnosed according to the European Academy of Allergy and Clinical Immunology guidelines for AX allergy. Upregulation of both CD63 and CD203c was flow-cytometrically assessed.

RESULTS

Analyses revealed that 1370 μmol/L and 685 μmol/L were the most discriminative stimulation concentrations for CD63 and CD203c upregulation, respectively, and a diagnostic threshold of 9% for positivity for both markers was identified. At these concentrations, sensitivity and specificity for CD63 upregulation were 13% and 100%, respectively, and for CD203c upregulation, 23% and 98%.

CONCLUSIONS

BAT with dual analysis of CD63 and CD203c is of poor performance to document AX allergy. The sensitivity is too low to let it occupy a prominent role in the diagnostic algorithm.

Beta-lactam hypersensitivity diagnosis in ambulatory and hospitalized settings require different approaches

BACKGROUND

Data on beta-lactam hypersensitivity (BLH) are mainly focused on immediate or mild nonimmediate reactions in the ambulatory setting, but limited in patients with concurrent illness and moderate-to-severe nonimmediate reactions in the hospitalized setting.

OBJECTIVE

To investigate the entire spectrum of BLH in Thai tertiary hospital.

METHODS

Clinical characteristics of 357 patients with suspected BLH were evaluated in a 7-year period. Culprit drug identification was performed in 335 patients by combined skin testing, in vitro testing, or drug provocation tests.

RESULTS

The predominant BLH presentations were non-immunoglobulin (Ig)E-mediated reactions with severe cutaneous adverse reactions of 18.9%, and BLH status was definitively confirmed in 18.1%. The most common verified culprits were cephalosporins (34.8%), particularly in hypersensitivity type IV reactions. Natural penicillins were the main implicated drugs in 48.5% of ambulatory patients. In contrast, cephalosporins and carbapenems were the main implicated drugs in hospitalized patients. Non-IgE-mediated anaphylaxis and serum sickness-like reaction remained diagnostically challenged. New generations of beta-lactams, hospitalized patients, recent allergic history, and underlying malignancies or autoimmune diseases were associated with increased BLH risk.

CONCLUSION

At present, cephalosporins are the leading causes of BLH, particularly in non-IgE-mediated reactions. More research on the verification of non-IgE hypersensitivity reactions from new generations of beta-lactams should be better emphasized.

CLINICAL TRIAL REGISTRATION

The registry was approved by the Ethics and Research Committee of the Faculty of Medicine, Chulalongkorn University, and listed on ClinicalTrials.gov (Identifier: NCT01667055; https://www.

CLINICALTRIALS

gov/ct2/show/NCT01667055).

Improving antimicrobial stewardship with penicillin allergy testing: a review of current practices and unmet needs

Penicillin allergy, the most frequently reported drug allergy, has been associated with suboptimal antibiotic therapy, increased antimicrobial resistance, increased rates of Clostridioides difficile colonization and infection, as well as extended hospital length of stay and increased cost. Although up to 10% of all patients may report penicillin allergy, most penicillin allergies are not confirmed. As such, most patients with a penicillin allergy can still safely use penicillin and related drugs following a more precise assessment. Herein, we review the current practices and unmet needs in penicillin allergy testing. The diagnostic algorithm is mostly based on a clinical history assessment followed by in vivo testing, i.e. skin test and/or drug challenge. As these tests are labour and resource intensive, there is increased interest in point-of-care penicillin allergy de-labelling solutions incorporated into Antimicrobial Stewardship Programmes including digital assessment tools. These can be locally parameterized on the basis of characteristics of target populations, incidence of specific allergies and local antibiotic usage to perform clinical risk stratification. Safely ruling out any residual risk remains essential and in vivo drug challenge and/or skin testing should be systematically encouraged. Gradual understanding and convergence of the risk stratification of the clinical presentation of penicillin allergy is enabling a wider implementation of this essential aspect of antimicrobial stewardship through digitalized decision tools and in vivo testing. More research is needed to deliver point of care in vitro diagnostic tools to democratize this de-labelling practice, which would be highly beneficial to patient care. This progress, together with better education of patients and clinicians about the availability, efficacy and safety of penicillin allergy testing, will increase the dissemination of penicillin allergy assessment as an important component of Antimicrobial Stewardship Programmes.

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.

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Contact allergies to topical antibiotic applications

Despite limited evidence on clinical efficacy and increasing resistance problems, topical antibiotics are still used in everyday clinical practice. However, topical antiseptic agents such, as octenidine and polyhexanide, often have a broader efficacy spectrum. They also have a broader target tropism because of their non-specific cellular mechanisms of action. Repeated use of topical antibiotics also carries the risk of contact sensitization, which could limit potential subsequent use as systemic antibiotics. Contact allergy is a clinically relevant problem, particularly in patients with barrier-damaged skin, pre-existing dermatosis, or occupational exposure. It can be concluded that with the use of modern antiseptics, topical antibiotic therapy is rarely indicated and should be avoided, not only because of the risk of contact sensitization but also because of the unfavorable and potentially consequential resistance problem.

Kleine Ursache – große Wirkung: Spättyp-Hauttests mit Medikamenten als Auslöser von disseminierten Rezidivexanthemen

Es werden zwei Patienten vorgestellt, die wegen eines streuenden allergischen Kontakt- bzw. Arzneimittelexanthems auf Budesonid bzw. Antibiotika abgeklärt wurden. Bei beiden trat innerhalb einiger Stunden nach Anlegen eines Epikutantests mit Budesonid bzw. Intradermaltesten mit Amoxicillin eine stark positive Hauttestreaktion sowie ein Exanthem auf. Beim ersten Patienten lag eine Sensibilisierung auf die kreuzreagierenden Moleküle Budesonid und Amcinonid, bei der zweiten Patientin eine ausgeprägte Überempfindlichkeit auf Aminopenizilline vor. Aufflammphänomene (Flare-ups) sind v. a. aus der Kontaktallergologie bekannt, können aber auch bei der Abklärung von allergischen Arzneimittelexanthemen auftreten. Systemische Reaktionen vom verzögerten Typ auf Spättyp-Hauttests mit Medikamenten sind relativ selten, können aber eine erhebliche Morbidität bewirken. Verschiedene Formen von Aufflammphänomenen in der Allergologie werden diskutiert.

75% negative skin test results in patients with suspected hypersensitivity to beta-lactam antibiotics: Influencing factors and interpretation of test results

Background

The diagnostic approach for beta-lactam (BL) drug hypersensitivity reactions (DHR) is based on the history, clinical signs, skin tests (ST), in vitro tests, and drug provocation tests (DPT). The aim of this study was to assess the performance of an allergy workup with ST in a real-world use.

Methods

In this cross-sectional study the rate of positive ST in subjects with suspected DHR to penicillins and cephalosporins was investigated. Of special interest were correlations of ST positivity: 1) to the time intervals between index reaction and the allergic work-up, 2) time interval from drug exposure to the onset of signs, 3) pattern of manifestation in delayed DHR and involvement of test area in the index reaction, and 4) potential advantage of patch testing in delayed DHR.

Results

175 patients were included between January 2018 and April 2019 (63.4% female), 45 (25.7%) with immediate DHR manifestation and 130 with delayed DHR manifestation (74.3%). A total of 44 patients (25.1%) had a positive ST (immediate DHR 37.8% versus 20.0% in delayed DHR). ST positivity decreased in both groups after 3 years from 47.8% [95%CI 29.2-67] to 23.5% [95%CI 9.6-47.3] in immediate DHR and 23.0% [95%CI 15-4-32.9] to 12.9% [95%CI 5.1-28.9] in delayed DHR. The proportion of positive ST was higher in patients with more severe forms of delayed DHR, and in subjects with a shorter latency period of onset of symptoms after drug exposure: 0-3d: 29.5% [95%CI 19.6-41.9] vs. >3d: 11.6% [95%CI 6.0-21.2]). No sensitization was shown in delayed urticaria or angioedema. ST done outside the skin area involved during the index reaction were negative in all cases (0/38 vs. 26/84 in cases with involved area). The combination of patch test and intradermal test (IDT) revealed an additional positive result in 2/77 cases. Additional in vitro testing reduced the proportion of negative test results to 72%.

Conclusion

In most patients with negative test results, we could not clarify the cause of the BL-associated adverse events even with further investigations (including DPT). How to prevent new drug-induced adverse events in such patients has hardly been investigated yet. Corresponding cohort studies could improve the data situation.

Pricktest als Provokation – schwere anaphylaktische Reaktion auf Hauttests mit Ceftriaxon bei beruflicher Exposition

Es werden zwei Patienten vorgestellt, die wegen eines Asthma bronchiale bei beruflichem Kontakt mit Ceftriaxon abgeklärt wurden. Bei beiden trat innerhalb von Minuten nach Anlegen eines Pricktests mit Ceftriaxon eine adrenalinpflichtige, anaphylaktische Reaktion auf. Systemische Reaktionen auf Hauttests mit Betalaktamantibiotika sind relativ selten, sie können auch bei Patienten mit vorausgegangenen milden Symptomen wie Urtikaria oder beruflichen Kontaktallergien auf Betalaktame auftreten. Als Risikofaktoren werden schwere Anaphylaxien in der Anamnese und ein kurzes Reaktionsintervall genannt. Eine korrekte Durchführung der Hauttests mit Titration und eine adäquate Überwachung sind zu beachten.

Update on Type-1 Allergy Diagnostics

Diagnostics in type-1 allergy rely on medical history and clinical examination. Extent and severity of signs and symptoms can be documented by standardized scores and questionnaires. Both skin prick test and intradermal test are useful for search of immunoglobulin E-mediated sensitizations but the availability of commercially available diagnostic extracts has been markedly reduced during the last years. Investigation of total and of specific serum IgE is the most important in vitro diagnostic analyte in type-1 allergy. Identification of the individual molecules to which patients are sensitized, known as molecular or component-resolved diagnostics (CRD), has recently markedly improved management of type-1 allergy to pollen, food and hymenoptera venoms. Main features of CRD are increased analytic sensitivity, detection of cross-reactivity and determination of individual sensitization profiles which allow for risk assessment and facilitate decisions for or against allergen immunotherapy. Basophil activation test as well as determination of selected biomarkers (e.g. tryptase) may also be helpful in some cases. If any allergy test is positive, one will have to distinguish reactions, which are clinically relevant, from those, which are not. In vivo provocation tests (e.g. nasal provocation, oral drug or food challenge) may help to clarify the relevance of a sensitization.

Drug-specific history, skin and in vitro tests can reduce the need for drug provocation tests in betalactam-hypersensitivity

BACKGROUND

Many patients report questionable drug hypersensitivity reactions (DHR) to betalactam antibiotics. A workup is required for objectivation. Direct drug provocation tests (DPTs) omitting a prior allergy workup are increasingly recommended as the primary diagnostic approach. However, apart from the risk of severe side effects, DPTs often are a scarce resource in overloaded healthcare-systems. We investigated how many cases can be solved by drug-specific history, drug-specific IgE, and skin tests obviating the need for DPT.

METHODS

We conducted a chart review in a retrospective cohort of 932 patients in an allergy outpatient centre from 2016 to 2017. Patients had been submitted to drug-specific history and specific IgE-, skin prick-, intradermal- and patch-tests with early and late readings with a series of penicillins and cephalosporins but DPTs were no option.

RESULTS

Overall, positive in vitro and/or skin tests were found in 96/932 (10.3%) patients. Drug-specific IgE was detected in 40/932 (4.3%) patients, 61/787 (7.8%) patients had positive skin tests. In vitro tests to Pencillin V showed the highest rate of positivity 24/479 (5.0%) and early readings of ampicillin the highest amongst the skin tests (3/49, 6.1%). Immediate skin tests were more often positive than delayed ones (75:45). The combination of all parameters including drug-specific history solved 346/932 (37.1%) cases while 586/932 (62.9%) remained unresolved. Self-reported DHR could be less often confirmed in females and young children (p < 0.05).

CONCLUSIONS

Testing with betalactams applying simple, cheap, and safe skin and blood tests can solve a third of DHR-cases on a high throughput scale.

Induction of penicillin tolerance during pregnancy: Allergological opinion on the recommendation of the current AWMF Guidelines on Diagnosis and Treatment of Syphilis (AWMF Registry No. 059-002)

Not available.

[Adverse Drug Effects - how to detect, how to avoid?]

There is no drug therapy without risk for toxicity. The patient must tolerate some toxic or idiosyncratic adverse events (e. g. hand foot syndrome). After life threatening adverse effects, one needs to screen (hyperkalemia). The sick-day-rule should be communicated with the informed patient as for example stopping SGLT2-inhibitors (loss of appetite, hypotension). The list of prescriptions should regularly criticized for dangerous or superfluous medicines (deprescribing).