Skin test concentrations for systemically administered drugs -- an ENDA/EAACI Drug Allergy Interest Group position paper

Neuromuscular blocking agent drug challenge: a literature review and protocol proposal with biological evaluation

BACKGROUND

Drug challenge is the gold standard for identifying causative agents of drug allergies. Although clinical guidelines have recently been published, they do not recommend neuromuscular blocking agent (NMBA) drug challenges. NMBA challenges are rendered difficult by the lack of homogeneity of routine allergy work-ups and the necessity of a specialised setting. Several scenarios support NMBA challenges, such as an ambiguous allergy work-up, a high suspicion of a false-positive skin test or identification of a well tolerated alternative NMBA strategy. Furthermore, routine allergy work-ups may not recognise non-IgE mechanisms, such as IgG or MRGPRX2, whereas drug challenges may reveal them. Finally, if the culprit NMBA is not identified, subsequent anaesthesia regimens will be challenging to implement, resulting in increased risk.

OBJECTIVES

This literature review discusses the indications, strategies, doses, monitoring methods, limitations, and unresolved issues related to drug challenges for NMBAs.

DESIGN

The literature review included randomised controlled trials, observational studies, reviews, case reports, series, and comments on humans.

DATA SOURCES

Studies were retrieved from databases (PubMed) and electronic libraries (OVID, EMBASE, Scopus, etc.).

ELIGIBILITY CRITERIA

All studies that referred to the NMBA challenge were included without publication date limitations.

RESULTS

NMBA challenge may be considered in NMBA anaphylaxis patients with inconclusive or ambivalent IgE diagnostic work-up under controlled conditions (presence of anaesthetists and allergists with continuous monitoring in a secured environment). To illustrate its utility, a case report of a double NMBA challenge in a patient with NMBA cross-reactivity is presented, along with biological explorations to detect subclinical cellular activation, a novel aspect of this procedure.

CONCLUSION

Drug challenges could be implemented during the NMBA allergy work-up under strict safety conditions at specialised centres with close collaboration between anaesthetists and allergists. This could decrease uncertainty and contribute to defining a safer strategy for subsequent anaesthetic drug regimens.

Immediate allergies to chlorhexidine: A series of pediatric cases from the French pharmacovigilance database: Immediate allergies to chlorhexidine: series of pediatric cases from the French pharmacovigilance database

BACKGROUND

Immediate allergic reactions to chlorhexidine have been clearly identified in numerous countries, generating governmental warnings worldwide.

OBJECTIVES

The aim of our study was to characterize (i) these allergies, which are less reported in pediatric populations, and (ii) the patient-at-risk profile so as to suggest preventive measures.

METHODS

In association with the allergy department and the regional pharmacovigilance center in Rennes University Hospital, France, a multicenter retrospective, descriptive, and observational study was conducted using data from the national pharmacovigilance database for the period of January 1, 2010 to June 30, 2020. Immediate allergies to chlorhexidine cases based on a clinical history compatible with an immunoglobulin E (IgE)-mediated reaction, along with positive allergic testing, were analyzed.

RESULTS

Of the 478 cases identified, 17 pediatric cases of immediate allergic reaction to chlorhexidine (13 cases of grades II-IV anaphylaxis) were retained for the analysis. For 58.8 % of these cases, a history of a previous more moderate reaction to the substance was identified. The reactions occurred most frequently in cases of domestic misuse (88.2 %, n = 15/17) of chlorhexidine to dress a wound. Recurrence was reported for two cases, later leading to severe reactions at each new exposure to the allergen, suggesting an aggravation mechanism.

CONCLUSION

The number of pediatric cases of immediate allergies to chlorhexidine has possibly been underestimated on account of insufficient knowledge of the allergy and in view of its common usage. Information on the method of caring for wounds among children and on the risk of allergic sensitization as well as exploring any unusual reaction to chlorhexidine application could reduce the number of allergic reactions.

Delayed Skin Testing for Systemic Medications: Helpful or Not?

Cutaneous adverse drug reactions collectively are delayed drug reactions such as morbilliform drug eruption and severe cutaneous adverse reactions (SCARs). Morbilliform drug eruption may wane over time, be the result of drug viral interactions, and be amenable to slow reintroduction or rechallenge, whereas SCARs are HLA class I restricted, T-cell-mediated reactions that demonstrate durable immunity and warrant lifelong avoidance. SCARs such as drug reaction with eosinophilia and systemic symptoms, Stevens-Johnson syndrome and toxic epidermal necrolysis, acute generalized exanthematous pustulosis, and generalized bullous fixed drug eruption often occur in the setting of multiple drugs dosed together. Collectively, they lead to significant morbidity, mortality, and drug safety concerns that could severely limit future treatment options. Currently, no single or combination of diagnostic tests for SCARs such as ex vivo or in vitro testing, in vivo (skin) testing, or other adjunctive tests such as HLA typing have 100% negative predictive value. In this "Controversies in Allergy Review" article, we review the current literature on delayed skin testing (patch and delayed prick/intradermal test) and critically assess the evidence base of its utility across different drugs and clinical phenotypes of delayed hypersensitivity reactions.

Basophil activation test is a complementary tool in the diagnosis of immediate reactions to platinum salts and taxanes

BACKGROUND

Delabelling pathways offer confirmatory diagnosis and can prevent unnecessary second-line therapies or drug desensitization procedures after chemotherapeutic hypersensitivity reactions (CHT-HSRs). However, these pathways rely on risky in vivo tests. Data on whether in vitro tests could be helpful are scarce. We assessed the role of basophil activation test (BAT) in the diagnosis of HSRs to platin salts (PSs) and taxanes (TXs) in a well-defined population featuring varied endophenotypes and severities of HSRs.

METHODS

We conducted a 3-year-long multicentric, prospective study with 121 suspected-immediate CHT-HSR patients. The allergy workup included clinical history (initial reaction based on Type I, cytokine release syndrome, and mixed phenotype's symptoms and if unable to fit in any of these, as "indeterminate"), skin testing (ST), and drug provocation testing (DPT), provided risk assessment was favorable. Final diagnosis classified patients as "hypersensitive," "non-hypersensitive," or "inconclusive." We performed BAT using CD63 and CD203c as activation markers in patients and controls. Patients underwent DPT regardless of BAT results to prevent bias.

RESULTS

ST positivity significantly correlated with skin involvement, Type I phenotype, cancer recurrence, and lifetime exposures before reactions. DPTs were negative in all indeterminate phenotype patients (p = .02) and those considered low-risk, whereas they were negative in 62% moderate-risk patients. 55% were confirmed as hypersensitive (mainly Type I reactions, p < .0001), 24% as non-hypersensitive (mainly TXs and indeterminate phenotypes), and 21% as inconclusive. BAT showed 79% sensitivity in Type I IgE-mediated reactions to PSs with a high correlation to ST.

CONCLUSIONS

BAT is a promising tool for delabelling and endotyping CHT-HSRs, especially Type I reactions to PSs, possibly identifying patients at risk of positive DPT. ST seems useful in confirming CHT-HSRs, especially PS-induced reactions, and DPT remains the gold standard, being essential even in moderate-risk patients.

Anaphylaxis after SonoVue: A Case Report and a Literature Review

SonoVue (Bracco, Milan, Italy) is a drug used in ultrasonography for the purpose of increasing the echogenicity of blood or fluids by improving the signal-to-noise ratio. Background/Objectives/Methods: We described a case of anaphylaxis due to SonoVue and performed a literature review. Results and Conclusions: We reported a case of anaphylaxis secondary to the administration of SonoVue and described all the 13 literature cases. Given its widespread use and the potentially dangerous nature of the reactions it can cause, it is advisable to know how to promptly recognize fatal reactions.

A Skin Testing Strategy for Non-IgE-Mediated Reactions Associated With Vancomycin

BACKGROUND

Vancomycin infusion reaction (VIR), reportedly mediated through Mas-Related G Protein-Coupled Receptor-X2, is the primary vancomycin-induced immediate drug reaction. Clinically, distinguishing the underlying drug-induced immediate drug reaction mechanisms is crucial for future treatment strategies, including drug restriction, re-administration, and pretreatment considerations. However, the lack of validated diagnostic tests makes this challenging, often leading to unnecessary drug restriction.

OBJECTIVE

To determine whether intradermal tests (IDTs) and, separately, the basophil activation test (BAT) differentiate VIR from vancomycin-tolerant subjects.

METHODS

This was a cross-sectional study of vancomycin-exposed adults with and without a history of VIR. Data on demographics, allergy-related comorbidities, history of vancomycin exposures, and VIR characteristics were collected. IDT with vancomycin was performed. IDT dose-response EC50, IDT-related local symptoms, and BAT results were compared between groups.

RESULTS

A total of 11 VIR and 10 vancomycin-tolerant subjects were enrolled. The most reported VIR symptoms were pruritus (82%), flushing (82%), hives (46%), angioedema (27%), and dyspnea (19%). The IDT dose-response mean EC50 was 328 μg/mL (95% CI, 296-367) in the VIR versus 1166 μg/mL (95% CI, 1029-1379) in the tolerant group (P < .0001). All VIR subjects reported IDT-related local pruritus compared with 60% of tolerant subjects (P = .0185). The %CD63+ basophils were consistently less than 2%, without significant differences between groups (P < .54).

CONCLUSIONS

Variations in skin test methodologies could help identify other immediate drug reaction mechanisms beyond IgE. This skin test protocol holds the potential for identifying VIR, particularly in cases where patients have received multiple drugs while BAT is insufficient. Future studies will validate and delineate its predictive value, assessing the risk of VIR.

Intradermal testing of iodinated contrast media: Should we test up to pure or with diluted compounds only?

BACKGROUND

Intradermal testing (IDT) with iodinated contrast media (ICMs) is an established diagnostic tool in patients with ICM hypersensitivity. Currently, it is unclear which test concentration is the more useful one, up to pure or up to 1:10 diluted ICMs.

METHODS

We searched the literature database PubMed for eligible papers dealing with ICM allergy and their IDT results. We analyzed the data presented by the papers and compared the pooled groups tested with diluted and undiluted ICMs.

RESULTS

We identified 29 eligible original papers, and extracted data of 1137 patients that formed the study population. Although in the cohort tested with diluted ICMs the number of tested ICMs was greater, the percentage of positive tests was significantly less (9.0% vs. 24.7%; P < 0.0001; OR 0.30 [0.26-0.34]). The frequency of positive tested culprit ICMs was also lesser in the group tested with diluted ICMs (31.0% vs. 72.5%; P < 0.0001; OR 0.17 [0.12-0.23]). The number of drug provocation tests (DPTs) was greater in patients with diluted IDTs (374 vs. 89; P < 0.0001; OR 2.54 [1.93-3.36]). We detected an increased sensitivity in patients with undiluted tests (0.774 vs. 0.282) and a nearly identical specificity in both groups (1 vs. 0.983).

CONCLUSIONS

For the first time, we show that IDT up to pure ICM concentrations is superior to using diluted ICMs only. Possibly, we can reduce the number of DPTs when performing IDTs with pure ICMs. In the undiluted group, there were no hints for skin irritations or unspecific test reactions.

Penicillin Allergy in China: Consequences of Inappropriate Skin Testing Practices and Policies

Penicillins are the most frequently prescribed class of medications worldwide and first-line antibiotic of choice for most bacterial infections. They are also commonly labelled as the culprit of drug 'allergy'; leading to obligatory use of second-line antibiotics, suboptimal antibiotic therapy and increased antimicrobial resistance. However, the majority of reported penicillin 'allergy' labels are found to be incorrect after allergy testing, emphasising the importance of proper drug allergy testing and evaluation. Penicillin skin testing (PST) remains an important component of drug allergy diagnosis; however, its practice and policies significantly differ across the world. Inappropriate and non-evidence-based PST practices can lead to consequences associated with allergy mislabelling. Even within different regions of China, with a population exceeding 1.4 billion, there are marked differences in the implementation, execution and interpretation of PST. This review aims to examine the differences in PST between Mainland China, Hong Kong and the rest of the world. We critically analyse the current practice of 'pre-emptive' PST in Mainland China, which has a significant false-positive rate leading to high levels of penicillin allergy mislabelling. Non-evidence-based practices further compound the high false-positive rates of indiscriminatory PST. We postulate that inappropriate PST policies and practices may exacerbate the mislabelling of penicillin allergy, leading to unnecessary overuse of inappropriate second-line antibiotics, increasing antimicrobial resistance and healthcare costs. We advocate for the importance of more collaborative research to improve the contemporary workflow of penicillin allergy diagnosis, reduce mislabelling and promote the dissemination of evidence-based methods for allergy diagnosis.

Polyethylene glycol hypersensitivity, patient outcomes in a 7-year retrospective study

BACKGROUND

Immediate IgE-mediated hypersensitivity reactions to polyethylene glycol (PEG) are rare. Our understanding of PEG hypersensitivity is limited.

OBJECTIVE

To evaluate the clinical characteristics and investigation outcomes of the largest cohort of patients with PEG allergy reported.

METHODS

A total of 44 patients investigated for suspected PEG allergy across 4 United Kingdom tertiary allergy centers between October 2013 and December 2020 were studied. Clinical characteristics, index reaction, and approaches to and outcomes of allergy investigations were analyzed.

RESULTS

PEG hypersensitivity was confirmed in 42 of 44 cases. Macrogol laxatives were the most common index drugs reported (23%), followed by depo-medroxyprogesterone (19%), oral penicillin V (10%), and depo-methylprednisolone (10%). In general, 61% experienced grade III anaphylaxis. Intradermal testing (IDT) increased the diagnostic sensitivity from 51% to 85%. Five patients experienced systemic reactions during IDT. Of the 5 patients, 2 were skin prick test positive to a high molecular weight PEG. Three patients with negative skin test results had positive drug provocation test results. Seven patients with PEG allergy reported tolerance to H1-antihistamines containing PEG. Administration of messenger RNA COVID-19 or Oxford/AstraZeneca COVID-19 vaccines was tolerated in all 16 patients to whom they were administered.

CONCLUSION

PEG hypersensitivity is an uncommon cause of drug-induced anaphylaxis. Four index drugs accounted for two-thirds of the cases, and reactions to these drugs should prompt PEG hypersensitivity investigations. PEG IDT increases diagnostic yield. The role of skin prick test with higher molecular weight PEGs requires further attention. Further studies are required to understand PEG thresholds and PEG equivalent doses of various administration routes. COVID-19 vaccines were tolerated by all exposed.

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.

Hypersensitivity reactions to anticancer chemotherapy and monoclonal antibodies: Safety and efficacy of desensitization

BACKGROUND

Hypersensitivity reactions to anticancer chemotherapy and monoclonal antibodies may lead to discontinuation of first-line treatment options. Identification of these reactions can provide specific diagnosis and treatment by rapid drug desensitizations.

OBJECTIVE

To determine the hypersensitivity reactions involved in anticancer chemotherapy and monoclonal antibodies, and the safety and efficacy of rapid drug desensitization.

METHODS

We conducted an observational study of hypersensitivity reaction presented after the administration of anticancer chemotherapy and monoclonal antibodies in Mexico. We documented the symptoms of initial reaction and their severity, and the results of skin tests. We also report our experience of the administration of 12-step (mild-moderate reactions) and 16-step (severe reactions) desensitization protocols in these patients.

RESULTS

Overall, 93 patients received 336 rapid drug desensitization; 105 to taxanes, 115 to platinum drugs, 101 to monoclonal antibodies, and 15 other anticancer chemotherapy. Hypersensitivity reaction to taxanes occurred in the first or second administration, platinum drugs after the sixth cycle, and rituximab in the first cycle. The most common symptom in carboplatin was urticaria, paclitaxel back pain, oxaliplatin and docetaxel dyspnea, and in the monoclonal antibodies cardiovascular symptoms. Skin tests were positive in 75% of the carboplatin group, and only 16.7% in docetaxel. There was a rapid drug desensitization success rate of 99.4% and 85.7% did not present any related hypersensitivity reaction.

CONCLUSION

The diagnosis of hypersensitivity reaction to anticancer chemotherapy and monoclonal antibodies offers a panorama in the management of oncological diseases. Our standardized desensitization protocol is safe and effective and can be reproduced in other centers to treat patients who need to maintain first-line treatment.

Drug hypersensitivity reactions: review of the state of the science for prediction and diagnosis

Drug hypersensitivity reactions (DHRs) are a type of adverse drug reaction that can occur with different classes of drugs and affect multiple organ systems and patient populations. DHRs can be classified as allergic or non-allergic based on the cellular mechanisms involved. Whereas nonallergic reactions rely mainly on the innate immune system, allergic reactions involve the generation of an adaptive immune response. Consequently, drug allergies are DHRs for which an immunological mechanism, with antibody and/or T cell, is demonstrated. Despite decades of research, methods to predict the potential for a new chemical entity to cause DHRs or to correctly attribute DHRs to a specific mechanism and a specific molecule are not well-established. This review will focus on allergic reactions induced by systemically administered low-molecular weight drugs with an emphasis on drug- and patient-specific factors that could influence the development of DHRs. Strategies for predicting and diagnosing DHRs, including potential tools based on the current state of the science, will also be discussed.

Cystic fibrosis: desensitization in delayed hypersensitivity reactions to elexacaftor/tezacaftor/ivacaftor

Background: Cystic fibrosis transmembrane conductance regulator modulators are the only available treatment for cystic fibrosis. Although elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) is well-tolerated, rash has been reported as very frequent. In severe rashes, ELX/TEZ/IVA withdrawal is necessary, leading to clinical deterioration. The objective of the study is to increment the experience of ELX/TEZ/IVA desensitization. Methods: Adult patients who developed a delayed hypersensitivity rash to ELX/TEZ/IVA between December 2021 and February 2023 and required withdrawal due to ineffective rescue medication were included. Skins test for ELX/TEZ/IVA and IVA were conducted to establish hypersensitivity mechanism. Balijepally ELX/TEZ/IVA desensitization protocol was selected. In cases where desensitization had to be discontinued due to rash, an extended desensitization was proposed. Clinical and health-related quality of life parameters were collected before ELX/TEZ/IVA and after desensitization. Results: 162 patients (81 women, 31.2 [23.8-42.5] years) started ELX/TEZ/IVA, developing rash 12 of them (7.4%, six women). Six patients (five women) required stopping ELX/TEZ/IVA and were selected for desensitization. Skin tests indicated delayed type-IV hypersensitivity in one patient. Two patients presented adequate tolerance to desensitization; while, four patients developed rash. Three of these patients, successfully concluded extended desensitization (one patient declined participation). No significant clinical deterioration or quality of life worsening was observed during desensitization; in fact, there was an improvement in practically all mesured parameters. All five patients who resumed ELX/TEZ/IVA are currently receiving therapy with good tolerance. Conclusion: Desensitization to ELX/TEZ/IVA could be a successful and safe strategy for reintroducing this essential treatment in cases of a delayed hypersensitivity rash.

Diagnostic evaluation of hypersensitivity reactions to arylpropionic acid derivatives: a descriptive observational study focusing on clinical characteristics and potential risk factors in children

BACKGROUND

Arylpropionic acid derivatives (APs) are the main triggers of nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity. Data on clinical patterns and risk factors for AP hypersensitivity in children are quite limited.

AIM

To assess the clinical characteristics and potential risk factors for proven AP hypersensitivity in children.

METHOD

Patients with a history of AP hypersensitivity were retrospectively assessed using a standardized diagnostic algorithm. Children with confirmed hypersensitivity were defined as selective responders or cross-intolerants based on the result of drug provocation tests and further categorized according to the EAACI/ENDA classification. A multivariable logistic regression analysis was performed to analyze the potential risk factors for proven AP hypersensitivity.

RESULTS

A total of 166 patients (51.2% male, median age of six years) with a history of AP hypersensitivity were included. Ibuprofen (89.2%) was the most frequently reported AP in the patients' histories. The reported hypersensitivity of 40 (22.4%) patients was confirmed by diagnostic testing: eight (13.6%) patients with a history of reaction only to APs and 32 (29.9%) patients with a history of reactions to multiple NSAIDs, including chemically unrelated NSAIDs in addition to APs. Five (12.5%) patients were classified as selective responders and 35 (87.5%) were cross-intolerants. Overall, five (12.5%) of the confirmed cases could not be categorized according to the EAACI/ENDA classification. Older age (aOR: 1.11, 95% CI 1.02-1.21, p = 0.015), chronic urticaria as an underlying disease (aOR: 2.87, 95% CI 1.09-7.54, p = 0.033) and a history of anaphylaxis (aOR: 7.84, 95% CI 1.86-33.04, p = 0.005) were related to confirmed AP hypersensitivity.

CONCLUSION

Almost a quarter of children and adolescents were confirmed to have AP hypersensitivity. Older age, the presence of chronic urticaria and a history of anaphylaxis were potential risk factors for proven AP hypersensitivity.

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

Background

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

Objective

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

Methods

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

Results

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

Conclusion

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

Lymphocyte transformation tests predict delayed-type allergy to piperacillin/tazobactam in patients with cystic fibrosis

BACKGROUND

Antibiotic treatment is crucial for patients with chronic bacterial infections. Suspected drug allergies often lead to inconsistent therapies and challenging clinical management for patients and caregivers. The objective of this study was to evaluate the value of lymphocyte transformation tests in comparison to skin tests for the prediction of delayed-type allergic reactions.

METHODS

This prospective, observational study tested the diagnostic value of skin prick tests, intradermal tests (reading: 15 min and 72 h) and lymphocyte transformations tests for the prediction of allergic reactions in CF patients with physician reported allergy to piperacillin/tazobactam, meropenem and ceftazidime. The tests were performed directly before a 14d intravenous drug challenge.

RESULTS

We performed 33 drug challenges in 29 subjects. 21 drug challenges were negative (63 %); 12 lead to a reaction (37 %), of those 2 were immediate and 10 were delayed-type. 100 % of the skin prick tests were negative. 97 % (33/34) of the intradermal tests with early reading and 100 % of the intradermal tests with late reading yielded negative results. 5/11 patients who experienced a delayed-type reaction during the drug challenge had a positive lymphocyte transformations test. All 17 patients who did not react had a negative lymphocyte transformations test. For piperacillin/tazobactam, 4/5 patients who experienced a delayed-type reaction during the drug challenge had positive lymphocyte transformations tests. Hence, for piperacillin/tazobactam, the sensitivity of the lymphocyte transformation test for prediction of reactions was 80.0 % and the specificity 100 %.

CONCLUSION

We demonstrate that the lymphocyte transformation test predicts delayed-type allergy to piperacillin/tazobactam in contrast to skin tests.

Knowledge mapping and global trends of drug hypersensitivity from 2013 to 2023: A bibliometric analysis

BACKGROUND

Drug hypersensitivity is a major global public health issue with a significant increase in prevalence in populations. Here, we provide a deep insight into the frontier hotspot and future direction in the field of drug hypersensitivity.

METHODS

A knowledge map is portrayed based on publications related to drug hypersensitivity from Web of Science Core Collection using CiteSpace. Co-occurrence relationships of countries, institutes, authors, journals, references, and keywords are constructed. According to the co-occurrence relationships, hotspots and future trends are overviewed.

RESULTS

The United States ranked first in the world and China with the second highest publications was the only developing country. Torres, Mayorga, and Blanca were highly productive authors. Harvard University was the institution with the most research publications. Keywords co-occurrence analysis suggested applications in emerging causes, potential mechanisms, and clinical diagnosis as the research hotspots and development frontiers.

CONCLUSION

Research on drug hypersensitivity is in a rapid development stage and an emerging trend in reports of anaphylaxis to polyethylene glycols is identified. Developing algorithms for understanding the standardization process of culprit drugs, clinical manifestations, and diagnostic methods will be the focus of future direction. In addition, a better understanding of the mechanisms to culprit drugs with immunological precise phenotypic definitions and high-throughput platforms is needed.

Effectiveness of Carboplatin-Prescreening Intradermal Skin Tests to Reduce Unanticipated Immediate Hypersensitivity Reactions: A Comparative Study

BACKGROUND

Carboplatin administration poses a risk of immediate hypersensitivity reactions (IHRs) that tend to increase with repeated administration and are mostly IgE-mediated.

OBJECTIVE

This study evaluated the usefulness of carboplatin-prescreening intradermal skin tests (IDTs).

METHODS

Carboplatin-prescreening IDTs were routinely conducted in patients with a history of receiving six or more carboplatin cycles beginning in January 2021. The primary objective was to assess disparities in the incidence of unanticipated IHRs to carboplatin administration. We compared patients in the intervention group (from 2021 to 2022) and those who did not undergo prescreening IDTs under the same conditions (preintervention group, from 2019 to 2020). Secondary objectives included evaluating the sensitivity and specificity of the prescreening IDT and the incidence of carboplatin IHR according to the number of infusion cycles.

RESULTS

The intervention group was composed of 67 patients who were administered 347 carboplatin cycles whereas the preintervention group included 96 patients who were administered 464 carboplatin cycles. The risk of unanticipated carboplatin IHRs decreased by 83.2% in the intervention group compared with results in the preintervention group (preintervention group, 3.45%, n = 16 vs intervention group, 0.58%, n = 2; P = .005). The prescreening IDT showed a sensitivity and specificity of 77.78% and 99.41%, respectively. The risk of newly developed IHRs based on the number of carboplatin cycles was less than 1% (cycles 1-5), 2.11% (cycle 6), 3.90% (cycles 7-12), 2.90% (cycles 13-18), and 0.74% (cycles 19 and greater), respectively.

CONCLUSIONS

Initiating carboplatin-prescreening IDTs from the seventh cycle on significantly reduced the risk of unanticipated IHRs.

Biomarkers of immediate drug hypersensitivity

Immediate drug hypersensitivity reactions (IDHRs) are a burden for patients and the health systems. This problem increases when taking into account that only a small proportion of patients initially labelled as allergic are finally confirmed after an allergological workup. The diverse nature of drugs involved will imply different interactions with the immunological system. Therefore, IDHRs can be produced by a wide array of mechanisms mediated by the drug interaction with specific antibodies or directly on effector target cells. These heterogeneous mechanisms imply an enhanced complexity for an accurate diagnosis and the identification of the phenotype and endotype at early stages of the reaction is of vital importance. Currently, several endophenotypic categories (type I IgE/non-IgE, cytokine release, Mast-related G-protein coupled receptor X2 (MRGPRX2) or Cyclooxygenase-1 (COX-1) inhibition and their associated biomarkers have been proposed. A precise knowledge of endotypes will permit to discriminate patients within the same phenotype, which is crucial in order to personalise diagnosis, future treatment and prevention to improve the patient's quality of life.

Perioperative hypersensitivity in children: A prospective multidisciplinary study

BACKGROUND

There are few studies of perioperative hypersensitivity reactions in children. The diagnosis of perioperative hypersensitivity reactions may be under estimated because it is difficult to recognize the reactions. Anaphylaxis may go unnoticed because of patient unconsciousness. Urticaria may be missed due to sterile drapes. The aim of this study was to prospectively evaluate perioperative hypersensitivity reactions.

METHODS

In this prospective study, patients with suspected perioperative hypersensitivity reactions aged 0-18 years who underwent surgery at the Department of Pediatric Surgery, Cerrahpasa Faculty of Medicine, between 2019 and 2021 were investigated. Suspected reactions in the perioperative period were graded according to the Ring and Messmer scale. Patients with suspected reactions were examined 4-6 weeks after the reaction. If necessary, specific IgE and basophil activation tests were performed. Reactions of grades III-IV were considered anaphylaxis. If one test modality was strongly positive and there was a relevant time point or repeated allergic reactions, or at least two test modalities were positive, hypersensitivity was confirmed. In all patients, serum tryptase levels were analyzed at the time of the reaction, 2 h after the reaction, and 4-6 weeks after the reaction as part of the allergic evaluation.

RESULTS

A total of 29 patients (8 female, 21 male) suspected of having an intraoperative reaction during the study were included in the analysis. Perioperative hypersensitivity reactions were noted in 1 patient. The incidence of perioperative hypersensitivity reactions was reported to be 0.03% (n = 1/2861). While anaphylaxis was confirmed in 1 patient, 5 patients were considered possible anaphylaxis cases.

CONCLUSION

Perioperative hypersensitivity reactions can be life-threatening and may recur with further administration. Collaboration between pediatric surgeons, anesthesiologists, and allergists can prevent further reactions. All suspected cases should be evaluated by an experienced allergist soon after the initial reaction.

EAACI/ENDA position paper on drug provocation testing

In drug hypersensitivity, drug provocation testing (DPT), also called drug challenge, is the gold standard for investigation. In recent years, risk stratification has become an important tool for adjusting the diagnostic strategy to the perceived risk, whilst still maintaining a high level of safety for the patient. Skin tests are recommended before DPT but may be omitted in low-risk patients. The task force suggests a strict definition of such low-risk patients in children and adults. Based on experience and evidence from studies of allergy to beta-lactam antibiotics, an algorithm on how to adjust DPT to the risk, and when to omit skin tests before DPT, is presented. For other antibiotics, non-steroidal anti-inflammatory drugs and other drugs, skin tests are poorly validated and DPT is frequently necessary. We recommend performing DPT with chemotherapeutics and biologicals to avoid unnecessary desensitization procedures and DPT with skin tests negative contrast media. We suggest DPT with anesthetics only in highly specialized centers. Specifics of DPT to proton pump inhibitors, anticonvulsants and corticosteroids are discussed. This position paper provides general recommendations and guidance on optimizing use of DPT, whilst balancing benefits with patient safety and optimizing the use of the limited available resources.

Local anesthetics allergy in children: Evaluation of diagnostic tests with Real-Life data

BACKGROUND

Local anesthetic (LA) drugs are commonly used in clinical practice to provide effective analgesia, including in dentistry and minor surgical procedures. The perception of a high risk of allergy in daily applications leads to the referral of atopic patients and those with other drug allergies to allergy clinics for the evaluation of allergic reactions to LA. The aim of this study was to determine who should be referred to the allergy clinic for LA allergy testing, assess the frequency of LA allergy in pediatric patients, and identify the negative predictive value of skin tests in diagnosis.

METHODS

January 2017-July 2023, the clinical and laboratory data, as well as the results of drug allergy tests, of patients referred to our pediatric allergy clinic by dentists and physicians performing minor surgical procedures with suspected LA allergy were retrospectively evaluated.

RESULTS

Our study included a total of 153 patients, comprising 84 girls (54.9%) and 69 boys (45.1%), with a mean age of 8.9 (±3.3) years. The most common reason for referral was a history of non-LA drug allergies (n = 66, 43.2%), followed by asthma (n = 25, 16.3%). Hypersensitivity reactions (HRs) with LA were most commonly associated with articaine (n = 7, 4.8%), followed by lidocaine (n = 6, 4.1%). When intradermal tests were evaluated, 17 patients (11.1%) had a positive test result. The positivity for lidocaine was 70.6% (n = 12), and prilocaine was 29.4% (n = 5). Subcutaneous provocation was administered to 109 patients (71.2%), and one patient exhibited local erythema and swelling with prilocaine.

CONCLUSION

Although LA allergy is a rare occurrence, consultations of this nature are frequently requested from allergy clinics in real life. Considering the negative predictive value of skin tests performed with LA drugs, the reaction rate appears to be low in patients with atopy or other drug allergies. It is crucial for all relevant healthcare professionals to be knowledgeable about the appropriate approach to suspected LA allergies to avoid unnecessary tests. To the best of our knowledge, our study is the most comprehensive work in the literature that evaluates the results of diagnostic tests in children referred with a suspicion of LA allergy.

An Update on Nonsteroidal Anti-Inflammatory Drug-Induced Urticaria

BACKGROUND

Hypersensitivity reactions to non-steroidal anti-inflammatory drugs (HR-NSAIDs) are common adverse events related to the widespread use of over-the-counter NSAIDs for the treatment of a variety of inflammatory conditions. Urticaria is the most commonly reported immediate cutaneous clinical sign of HR-NSAIDs, but it can be a manifestation of pathophysiologically different clinical entities that require different therapeutic strategies. The aim of this study is to ease the identification of the correct phenotype of HR-NSAIDs in patients reporting urticaria associated with the intake of NSAIDs and provide updated information about their diagnosis and management.

METHODS

The study is a narrative review conducted by collecting the most relevant and up-todate data related to the classification, pathophysiology, severity, and prognosis of NSAID hypersensitivity reactions. PubMed and Embase scientific databases were used as search engines to select relevant articles.

RESULTS

Patients developing HR-NSAIDs can be divided into two categories: selective responders (SR), who develop reactions after the administration of a single specific NSAID due to an underlying IgE or T-cell mediated hypersensitivity mechanism, or cross-intolerant (CI), who develop reactions to more than one chemically unrelated NSAIDs due to abnormalities in the biochemical pathways related with prostaglandin metabolism, independently from an underlying immunological mechanism. Five major different categories of HR-NSAIDs have been identified: NSAIDs-exacerbated cutaneous disease (NECD), NSAIDs-induced urticaria/angioedema with/without respiratory and systemic symptoms of anaphylaxis (NIUAA), and NSAIDsexacerbated respiratory disease (NERD), which are developed by CI patients, and single NSAIDs-induced urticaria, angioedema and/ or anaphylaxis (SNIUAA) and single NSAIDsinduced delayed hypersensitivity reactions (SNIDHR), which are developed by CI patients. In vivo and in vitro diagnostic tests have rarely been shown to be reliable in all these entities and therefore are not routinely used in clinical practice. The management in SR patients consists of strict avoidance of the culprit drug, while for cross-intolerance reactions oral tolerance tests with safe alternative drugs (e.g. weak COX-1 inhibitors or selective COX-2 inhibitors) can be performed.

CONCLUSION

HR-NSAIDs are being observed with increasing frequency, however, the pathogenesis behind some NSAIDS-associated clinical entities is still unclear. Diagnosis is mostly based on a thorough clinical history and confirmed by a drug challenge test. Clinical management is based on strict avoidance and use of alternative tolerated medications. Overall, all therapeutic decisions depend on the correct identification of the type of reaction the patient experienced.

Drug reaction with eosinophilia and systemic symptoms in a paediatric population: Interest of skin tests

BACKGROUND

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe adverse drug reaction. It is uncommon in the paediatric population and can be difficult to diagnose as its initial symptoms may mimic a viral infection.

OBJECTIVE

To analyse the features of paediatric DRESS and to evaluate the interest of skin tests in identifying the causative drugs.

METHODS

It is a retrospective analysis (2004-2021) of DRESS cases diagnosed in paediatric patients. The DRESS diagnosis was defined using the RegiSCAR scoring. The skin tests were performed according to the ENDA recommendations.

RESULTS

We included 19 cases of DRESS occurred in 18 patients. Common clinical symptoms were exanthema and fever in 94.7% of cases each. The most commonly affected organ was the liver (84.2%). Among the implicated drugs, 16 were tested and skin tests were positive in 75%. To assess cross-reactivity and co-sensitization, skin tests with related and/or co-administered drugs were performed in eight patients. Among them, only one child had positive results.

CONCLUSION

Early diagnosis of DRESS and discontinuation of the incriminated drug might reduce the incidence of mortality in the paediatric population. Skin tests could be a safe and useful tool to identify the causative drug and assess cross-reactivity.

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.

Skin Test-Guided Strategy to Select Alternative Iodinated Contrast Media in Patients With Immediate Hypersensitivity Reaction: A Prospective Confirmative Study

BACKGROUND

Iodinated contrast media (ICM) are a common cause of drug-induced immediate hypersensitivity reaction (IHR). Repeated use of ICM is often necessary; therefore, a standardized protocol to prevent recurrence of IHR is required.

OBJECTIVE

We aimed to propose an intradermal skin test (IDT)-guided strategy for previous reactors to prevent recurrence of IHR.

METHODS

We conducted a prospective multicenter study from May 2018 to December 2020 and recruited patients who had experienced IHR to ICM. Once enrolled, the participants underwent IDT with a causative ICM. The alternatives for reexposure were selected using the following protocol: (1) if the IDT with the culprit ICM was positive, further skin tests with other available ICM were conducted to choose IDT-negative agents as alternatives, and (2) if the IDT with the culprit ICM was negative, a randomly changed ICM was used without additional skin tests. The recurrence and severity of hypersensitivity were assessed in subsequent computed tomography examinations. Premedication was administered according to the severity of the index event in all cases.

RESULTS

A total of 496 participants were enrolled, and 299 were reexposed to ICM. Among 269 participants who followed the protocol, 228 (84.8%) completed computed tomography examinations without adverse reactions, and IHR recurred in 16 of 30 participants (53.3%) who did not follow the protocol (P < .001). In addition, application of the protocol reduced the severity of IHR in recurred cases (P = 0.003).

CONCLUSIONS

Our IDT-guided strategy not only reduced recurrence of IHR to ICM but also mitigated the severity in recurred cases. This provides evidence for recommending an IDT to diagnose ICM allergy and find safe alternatives.

Meropenem allergy testing performed at the bedside of hospitalized patients labelled with a penicillin allergy

BACKGROUND

Meropenem is a widely prescribed beta-lactam for hospitalized patients. There are few data on meropenem allergy assessments in inpatients with a reported history of penicillin allergy who require a treatment with meropenem. This can lead to the use of less effective second-line antibiotics that may increase antibiotic resistances. We aimed to evaluate the clinical outcomes of a meropenem allergy assessment in admitted patients with a reported history of penicillin allergy that required meropenem for the treatment of an acute infection.

METHODS

A retrospective analysis was performed on 182 inpatients labelled with a penicillin-allergy who received meropenem after an allergy assessment. The allergy study was performed bedside if meropenem was required urgently. The study included skin prick tests (SPTs) followed by an intradermal skin test (IDT) to meropenem, and a meropenem drug challenge test (DCT). If a non-immediate reaction to a beta-lactam was suspected, it was initiated with patch tests.

RESULTS

The median age of the patients was 59.7 years (range 28-95) and 80 (44%) were women. A total of 196 sets of diagnostic workups were performed, with 189 (96.4%) of them being tolerated. Only two patients had a positive meropenem IV DCT, both presenting a non-severe cutaneous reaction that completely resolved after treatment.

CONCLUSIONS

This study evidenced that a bedside meropenem allergy assessment of hospitalized patients labelled with a 'penicillin allergy' who require a broad-spectrum antibiotic for empiric coverage is a safe and effective procedure, avoiding the use of second-line antimicrobial agents.

Drug Allergy in Children: Adverse Reactions after Skin Testing

INTRODUCTION

Skin tests are one of the most widely used diagnostic tools for suspected drug allergies in children. Studies on systemic reactions occurring during skin testing with allergens have mostly been conducted in pediatric and adult patient groups together. However, data on adverse reactions including allergic reactions after drug skin tests in children are scarce. It is aimed to determine the adverse reactions after skin test in children with suspected drug allergy.

METHODS

Patients who underwent a drug skin test due to the suspicion of drug allergy between May 2017 and June 2020 were evaluated, retrospectively. Data about adverse reactions seen after skin testing at the testing area in the clinic were analyzed.

RESULTS

The study included 1,073 children (585 [54.5%] boys and 488 [45.5%] girls) with a median age of 7.5 years. A total of 12 (1.1%) reactions were detected after skin testing, and 4 (0.4%) of them were allergic reactions. Of the allergic reactions, three were anaphylaxis and one was urticaria. Two of the reactions (1 anaphylaxis and 1 urticaria) were detected after the skin prick test and the remaining 2 were detected after intradermal test. Three of the nonallergic reactions were considered as vasovagal reactions and seven were considered as nonspecific and anxiety-related reactions.

CONCLUSION

Although drug skin tests were generally well-tolerated and adverse reactions were rare, severe allergic reactions including anaphylaxis may ensue. Skin tests should be necessarily performed in clinical settings in experienced centers.

Practical Approach to Hypersensitivity to Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) in Children

BACKGROUND

We aimed to assess the real-life prevalence, patient profile, and clinical presentation of drug hypersensitivity to NSAIDs in children after an incidence of an adverse event during treatment, verified by a drug challenge test.

METHODS

We included 56 children, aged 4-18 years, referred to our allergy clinic due to the incidence of adverse reaction during treatment. Skin prick tests and a drug provocation test were performed in all patients. Diagnostics for persistent urticaria were performed.

RESULTS

In 56 patients suspected of drug allergy, we proved NSAID hypersensitivity in 17 patients (30.1%). In 84.9% (n = 47) of patients, the clinical manifestations of hypersensitivity revealed angioedema and urticaria. The most common culprit drug among NSAIDs in children was ibuprofen. Thirty-one (55.4%) reactions were immediate, and 25 (44.6%) were delayed or late. Previous history of allergy was a risk factor for NSAID hypersensitivity (p = 0.001). Vitamin D deficiency in the blood serum was a risk factor for NASID hypersensitivity (OR = 5.76 (95% Cl: 1.42-23.41)).

CONCLUSIONS

Hypersensitivity to NSAIDs is a difficult diagnostic problem in pediatric allergy. The most common manifestation of hypersensitivity to ibuprofen in children is acute urticaria and angioedema. Two important problems in the differential diagnosis are cofactors such as vitamin D levels and viral infections, which require further research.

[Reproducibilidad clínica de reacciones de hipersensibilidad a fármacos en pruebas de exposición controlada]

Objective

To assess the reproducibility of symptoms in drug challenge tests.

Methods

The study included patients with positive cutaneous or challenge test throughout 2019. For each patient, clinical suspicion according to Karch-Lasagna algorithm was registered. Primary outcome was the reproducibility of symptoms in the provocation tests using a paired analysis of data with McNemar test.

Results

Eighty-nine patients were included, 16 of them presented more than one positive test. Thirty were skin tests positive and 75 reacted to provocation tests. Eighty nine percent of patients who reacted in challenge test were probably or possibly reactors according to Karch-Lasagna scale. Symptoms of initial reaction did not differ from those triggered in challenge tests.

Conclusions

Karch-Lasagna scale is useful in predicting the response to drug provocation tests. In most of the positive studies, results were suggested by clinical history and no differences were found between symptoms triggered in challenge test and that referred to in the previous reaction.

Anaphylactic reaction to carboplatin diagnosed by skin testing-a reliable tool in platinum-based immediate-type hypersensitivity reactions

Immediate-type hypersensitivity reactions (IHRs) to carboplatin (CA) are most commonly reported in ovarian cancer patients. A 54-year-old woman with stage IV melanoma suffering from metastasis in the entire right lower extremity was presented to our allergy outpatient clinic for diagnostic work-up due to an anaphylactic reaction with palmoplantar erythema, conjunctivitis along with facial erythema, and an incipient decrease in blood pressure during a chemotherapy regimen with dacarbazine and carboplatin upon re-administration. A subsequently carried out allergological work-up with skin testing (ST) revealed CA to be the culprit drug, whereas cisplatin (CI) was confirmed to be a safe alternative for the patient for following treatments. Here, we report a case of an IHR to carboplatin in a melanoma patient, with CI serving as a safe alternative diagnosed by skin testing.

Clinical Application of In Vitro Tests for COVID-19 Vaccine Delayed Hypersensitivity Diagnostics

Drug hypersensitivity reactions can be classified as immediate or delayed. While diagnostic options for immediate reactions are well developed and standardized, delayed reactions (in many cases type IV according to Gell and Coombs) are a challenge for allergy work-up. In recent years, some in vitro markers have been proposed and used for delayed reactions, such as contact dermatitis. Primary strategy: Avoidance is difficult to achieve, especially for COVID-19 vaccinations, when immunity against infection is extremely important. The aim of our study was to evaluate the application of in vitro delayed hypersensitivity tests in COVID-19 vaccines. Seven patients with a positive history of severe delayed drug allergy were enrolled. Vein blood was collected to stimulate cells with the tested vaccines (Comirnaty, Janssen, Spikevax) and excipients with the assessment of CD40L, CD69, IL-2, IL-4, IL-6, IL-10, IFNgamma, TNFalfa, and intracellular markers: granulysin and INFgamma. In addition, basophile activation tests, patch tests, skin prick tests, and intradermal tests were performed with the tested vaccine. Finally, the decision was made to either administer a vaccine or resign. Two out of seven patients were considered positive for drug hypersensitivity in the in vitro test according to the high vaccine stimulation index measured with CD69 (6.91 and 12.18) and CD40L (5.38 and 15.91). All patch tests, BATs, and skin tests were negative. Serum interleukin measurements were inconclusive as the impact of the vaccine itself on the immunity system was high. Intracellular markers gave uncertain results due to the lack of stimulation on the positive control. CD69 and CD40L could be reliable in vitro markers for delayed hypersensitivity to COVID-19 vaccines. Patch tests, skin tests, BATs, and serum interleukins did not confirm their usefulness in our study.

Tools for Etiologic Diagnosis of Drug-Induced Allergic Conditions

Drug hypersensitivity reactions are a serious concern in clinical practice because they can be severe and result in lifelong sequelae. An accurate diagnosis and identification of the culprit drug is essential to prevent future reactions as well as for the identification of safe treatment alternatives. Nonetheless, the diagnosis can be challenging. In vivo and in vitro tests can be helpful, although none are conclusive; therefore, the tests are not usually performed in isolation but as part of a diagnostic algorithm. In addition, some in vitro tests are only available in research laboratories, and standardization has not been fully accomplished. Collaborating research is needed to improve drug hypersensitivity reaction diagnosis. In this review, we update the current available in vivo and in vitro tools with their pros and cons and propose an algorithm to integrate them into clinical practice.

Perioperative anaphylaxis: when the allergological work-up goes negative

PURPOSE OF REVIEW

Perioperative anaphylaxis (POA) is rare but is associated with significant morbidity and mortality. Patients are referred to the allergist to identify the mechanism of the reaction, the causative agent and make recommendations regarding subsequent anaesthesia. Despite a well conducted allergological evaluation, the causative agent is not found in 30-60% of these reactions, leaving patients without a well established diagnosis.

RECENT FINDINGS

Several mechanisms can induce POA. In addition to the well known IgE-mediated reactions, IgG-mediated reaction, MRGPR-X2-related reaction or nonspecific histamine release may be involved. These situations are not easily assessed by the allergological workup.

SUMMARY

When the allergological workup is negative, the situation should be reassessed with the team present at the time of the reaction to confirm the reality of the hypersensitivity reaction and to search for a possible differential diagnosis. If POA is confirmed, the allergological evaluation should be repeated, ensuring proper execution according to current guidelines and including the search for hidden allergens. Specific IgE assays or basophil activation tests may be of interest. In case of negative results, a closely monitored drug challenge test, in coordination with the anaesthesia teams, may be useful to avoid the exclusion of any drug injected during the reaction.

Hypersensitivity Reaction and Rapid Drug Desensitization with Chemotherapeutics: A Tertiary Reference Center Experiences

INTRODUCTION

Chemotherapy drugs have been in our lives for a long time, and all agents have the potential to develop hypersensitivity. Rapid drug desensitization is an option when hypersensitivity develops. The aim of this study was to examine the characteristics, diagnostic processes, and treatment results of patients with chemotherapeutic agent hypersensitivity who applied to our tertiary reference center.

METHODS

Patients who applied to our tertiary allergy outpatient clinic between January 2016 and September 2022 due to chemotherapy-induced drug hypersensitivity were examined. Demographic data of the patients, cancer diagnoses, chemotherapy regimens, skin tests, premedication scheme, desensitization cycle were evaluated. We applied a 16-step desensitization in patients with index reaction anaphylaxis or positive skin tests. If the index reaction was not anaphylaxis or skin tests were negative, we applied a 12-step desensitization. If the prick test with chemotherapeutic drugs was negative especially with taxanes, premedication was administered. We used the montelukast, cetirizine, and methylprednisolone for premedication.

RESULTS

Fifty-one patients were evaluated; 35 (68.6%) were female. The most common malignancy was colorectal cancer in 17 (33.3%) patients. The most common agent responsible for hypersensitivity was oxaliplatin in 17 (33.3%) patients, followed by paclitaxel in 13 (25.4%). When the symptoms of immediate reaction to chemotherapeutic drugs were analyzed as described in the EAACI position paper, only skin and mucosal involvement was seen in 24 (46.8%) patients; only respiratory system involvement or back pain was seen in 3 (6.2%) patients; multisystem involvement meeting the criteria for anaphylaxis was seen in 24 (47%) patients. Skin test was positive in 17 (56.6%) of 30 patients who developed a reaction with platin. Prolonged anaphylaxis was developed in 1 patient, and desensitization was not performed again. Fifty of 51 patients were able to receive the target chemotherapy dose by desensitization. In total, a 172-step desensitization was applied to 51 patients.

CONCLUSION

If completing the cycle is considered a treatment success, this was achieved in 98% (50/51) patients with rapid drug desensitization. This gives us the opportunity to use first-line chemotherapy agents.

An Unusual IgE-Mediated Hypersensitivity: Two Case Reports of Paracetamol Allergy

Paracetamol is one of the most commonly used analgesic and antipyretic agents worldwide, attributed in part to its excellent safety profile when administered at recommended doses. Paracetamol allergy is not common, and the majority of the reactions are related to the pharmacological action of cyclooxygenase 1 inhibition. Selective and Immunoglobulin E (IgE)-mediated hypersensitivity reactions are rare. In this article, the authors report two cases of paracetamol allergy in which the mechanism of IgE-mediated hypersensitivity was demonstrated by positive skin tests and basophil activation tests. We highlight the relevance of identifying the mechanism underlying the reaction since patients with IgE-mediated paracetamol allergies will be able to tolerate non-steroidal anti-inflammatory drugs.

The state and consideration for skin test of β-lactam antibiotics in pediatrics

β-lactam antibiotics are the most frequently used drugs and the most common drugs that cause allergic reactions in pediatrics. The occurrence of some allergic reactions can be predicted by skin testing, especially severe adverse reactions such as anaphylactic shock. Thus, penicillin and cephalosporin skin tests are widely used to predict allergic reactions before medication in pediatrics. However, false-positive results from skin tests were more often encountered in pediatrics than in adults. In fact, many children labeled as allergic to β-lactam are not allergic to the antibiotic, leading to the use of alternative antibiotics, which are less effective and more toxic, and the increase of antibiotic resistance. There has been controversy over whether β-lactam antibiotics should be tested for skin allergies before application in children. Based on the great controversy in the implementation of β-lactam antibiotic skin tests, especially the controversial cephalosporin skin tests in pediatrics, the mechanism and reasons of anaphylaxis to β-lactam antibiotics, the significance of β-lactam antibiotic skin tests, the current state of β-lactam antibiotic skin tests at home and abroad, and the problems of domestic and international skin tests were analyzed to determine a unified standard of β-lactam antibiotic skin tests in pediatrics to prevent and decrease adverse drug reactions, avoid waste of drugs, and a large amount of manpower and material resource consumption.

Evaluation and Updated Classification of Acute Hypersensitivity Reactions to Nonsteroidal Anti-Inflammatory Drugs (NSAIDs): NSAID-Exacerbated or -Induced Food Allergy

BACKGROUND

There are hypersensitivity reactions (HRs) to foods in which nonsteroidal anti-inflammatory drugs (NSAIDs) act as aggravating factors (NSAID-exacerbated food allergy [NEFA]) or cofactors (NSAID-induced food allergy [NIFA]), often misdiagnosed as HRs to NSAIDs. Urticarial/angioedematous and/or anaphylactic reactions to two or more chemically unrelated NSAIDs do not meet current classification criteria. However, they may be considered part of a cross-reactive type of acute HR, which is NSAID-induced urticaria/angioedema with or without respiratory or systemic symptoms of anaphylaxis.

OBJECTIVE

To evaluate patients reporting acute HRs to NSAIDs and classify them according to updated criteria.

METHODS

We prospectively studied 414 patients with suspected HRs to NSAIDs. For all whom met these criteria, NEFA/NIFA was diagnosed: (1) mild reactions to (NEFA) or tolerance of (NIFA) the suspected foods without taking NSAIDs; (2) cutaneous and/or anaphylactic reactions to the combination foods plus NSAIDs; (3) positive allergy tests to the suspected foods; and (4) negative drug challenges (DCs) with the NSAIDs involved.

RESULTS

A total of 252 patients were given the diagnosis of NSAID hypersensitivity (60.9%), 108 of whom had NSAID-induced urticaria/angioedema with or without respiratory or systemic symptoms of anaphylaxis. We excluded NSAID hypersensitivity in 162 patients (39.1%) who tolerated DCs with the suspected NSAIDs, nine of whom received a diagnosis of NEFA, and 66 of NIFA. Pru p 3 was implicated in 67 of those 75 patients who received a diagnosis of NEFA or NIFA.

CONCLUSIONS

NEFA and NIFA account for about 18% of patients reporting HRs to NSAIDs, in which Pru p 3 is the main responsible food allergen. Therefore, patients with cutaneous and/or anaphylactic reactions to NSAIDs should be carefully questioned about all foods ingested within 4 hours before or after NSAID exposure, and targeted food allergy tests should be considered in the diagnostic workup of these patients. If testing is positive, DCs with the suspected NSAIDs should also be considered.

[Diagnostics of drug allergies and intolerances]

The prevalence of hypersensitivity reactions to drugs is increasing. Currently, this affects more than 7% of the world population. Nonsteroidal anti-inflammatory drugs (NSAID) and beta-lactam antibiotics (BLA) are by far the most common pharmaceutical preparations involved in hypersensitivity reactions to drugs. Misdiagnoses are frequent and BLA allergies present a danger that can lead to adverse health outcomes. Therefore, delabeling (exclusion of a suspected diagnosis) is paramount for those affected. Following the occurrence of uncomplicated maculopapular exanthemas, outpatient oral drug provocation can be safely considered in children without prior skin tests. Immediate perioperative reactions are rare. The approach to studying these complex reactions requires collaboration between allergologists and anesthesiologists to provide the best possible care for these patients.

[Reasons for allergology consultations prior to COVID-19 vaccination and their outcomes : Two-year experience of an allergy center in North Rhine-Westphalia]

BACKGROUND

To counteract the coronavirus disease 2019 (COVID-19) pandemic, several severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) vaccines have been licensed since December 2020. Shortly after the start of the vaccination campaigns, occasional allergic reactions related to vaccines were described, thus, leading to concerns in many patients with a history of allergies. The aim of this work was to evaluate which anamnestic events represented a reason for an allergology work-up before COVID-19 vaccination. Furthermore, the results of the allergology diagnostics are described.

METHODS

We performed a retrospective data analysis of all patients who presented at the Center for Dermatology, Allergology and Dermatosurgery of the Helios University Hospital Wuppertal during the years 2021 and 2022 for allergology work-up prior to COVID-19 vaccination. Demographic data, allergological history, reason for the consultation in the clinic and results of allergology diagnostic tests including reactions after vaccination were included.

RESULTS

A total of 93 patients presented for allergology work-up with COVID-19 vaccines. In about half of the cases, the reasons for the presentation to the clinic were doubts and concerns about allergic reactions and side effects. In all, 26.9% (25/93) of the presented patients had not previously received a COVID-19 vaccine yet and 23.7% (22/93) of patients developed non-allergic reactions after prior COVID-19 vaccine (e.g., headache, chills, fever, malaise). Of the patients, 46.2% (43/93) were successfully vaccinated in the clinic due to a complex allergological history, while the remaining 53.8% (50/93) were subjected to outpatient vaccination in the vaccination practice. Only one patient with known chronic spontaneous urticaria developed a mild angioedema of the lips a few hours after vaccination; however, we do not consider this episode an allergic reaction to the vaccine due to the time delay.

CONCLUSION

Allergic reactions after COVID-19 vaccines are rare, but many patients with a positive medical history of allergies are concerned about allergic reactions after COVID-19 vaccination. Thus, public work by practicing allergologists is important during vaccination campaigns to meet the concerns and fears of the population, especially of patients with allergies in their medical history.

Allergy to Local Anesthetics is a Rarity: Review of Diagnostics and Strategies for Clinical Management

Local anesthetics (LA) are commonly used in procedures and in topical agents for pain management. With the increasing use of LA drugs, the management of LA reactions is more frequently encountered in the office and in operating rooms. True allergic reactions involving IgE-mediated reactions and anaphylaxis are rare; they have only been identified in case reports and account for less than 1% of adverse LA reactions. Most reactions are non-allergic or are a result of hypersensitivity to other culprits such as preservatives, excipients, or other exposures. LA reactions that are misclassified as true allergies can lead to unnecessary avoidance of LA drugs or delays in surgical procedures that require their use. A detailed history of prior LA reactions is the first and most crucial step for understanding the nature of the reaction. Reactions that are suspicious for an immediate hypersensitivity reaction can be evaluated with skin prick and intradermal testing with subsequent graded challenge. Reactions that are suspicious for a delayed hypersensitivity reaction can be evaluated with patch testing.

Immediate Hypersensitivity to Chlorhexidine: Experience from an Allergy Center in China

BACKGROUND

Chlorhexidine generally has a good safety profile. However, allergic reactions are reported with increasing frequency. In China, it is rarely reported, and its characteristics are unknown. The purpose of this study was to summarize the experience of a Chinese allergy center with chlorhexidine allergy.

METHODS

The authors retrospectively reviewed all patients who underwent chlorhexidine allergy testing in the Allergy Center of West China Hospital, Sichuan University (Chengdu, China), in the period February 2018 to May 2022 (n = 43 patients) and included the patients diagnosed with chlorhexidine allergy for analysis.

RESULTS

Ten patients who were diagnosed by skin prick and serum-specific immunoglobulin E tests were included. They experienced a total of 30 allergic reactions to chlorhexidine (mean ± SD, 3.0 ± 1.3). Five patients experienced six allergic reactions (6 of 30, 20%) during general or local anesthesia, and they may have been exposed to chlorhexidine via different routes. Only one allergic reaction (1 of 30, 3%) was recorded with exposure via a mouthwash. The other 23 allergic reactions (23 of 30, 77%) were caused via a skin disinfectant; the route of exposure was IV cannulation in 22 allergic reactions (22 of 23, 96%) and broken skin in one allergic reaction (1 of 23, 4%). The symptoms included a quick onset and great severity. Two patients (2 of 10, 20%) had been accidentally re-exposed to chlorhexidine after diagnosis.

CONCLUSIONS

This study conducted in China showed that the majority of reactions to chlorhexidine were attributed to skin disinfectants, and IV cannulation was the most common exposure route; in general, however, chlorhexidine allergy was easily overlooked. The potential allergenicity of chlorhexidine used for skin preparation before IV cannulation or should be considered in patients who develop allergic reactions perioperatively.

EDITOR’S PERSPECTIVE

Clinical validation of the basophil activation test in immediate hypersensitivity reactions to gadolinium-based contrast agents

Gadolinium based contrast agents (GBCAs) are safe compounds globally used in magnetic resonance imaging (MRI). However, in last years it has been detected an increase of immediate hypersensitivity reactions (IHRs) to them. Diagnosis of IHRs to GBCAs is based on clinical symptoms, skin tests (STs) and drug provocation test (DPT). But DPTs are not without risks, thus it is important to implement an in vitro alternative method such as the basophil activation test (BAT). We described the clinical validation of the BAT using ROC curves from a control population formed by 40 healthy individuals without previous reactions to any contrast agents and 5 patients suffering from IHRs to GBCAs. Four patients presented IHRs to gadoteric acid (GA) as the culprit agent and another one to gadobutrol (G). Basophil reactivity was measured in percentage of CD63 expression and in stimulation index (SI). The optimal cut-off with the highest sensitivity (S) and specificity (E) for the GA was of 4.6% at 1:100 dilution (S = 80% and E = 85%; AUC = 0.880, p = 0.006). For the SI with GA, the cut-off of highest sensitivity and specificity was of 2.79 at 1:100 dilution (S = 80% and E = 100%; AUC = 0.920, p = 0.002). Sensitivity did not show differences between STs regarding the BAT (p < 0.05). Moreover, the BAT was able to detect one case with IHR to GA which had negative STs. Therefore, the BAT is a useful method in diagnosis of IHRs to GBCAs.