Intradermal Test Research Articles

Allergic rhinitis: a brief overview of the etiopathogenesis and rehabilitation of patients

The article presents a brief overview of modern literature sources concerning the prevalence, etiopathogenetic approaches in the diagnosis and treatment of allergic rhinitis. The relevance of the problem under consideration is due to the high prevalence of this pathology, the variety of etiopathogenetic mechanisms and the variability of classifications. One of the most popular classifications is seasonal. When studying pathogenetic mechanisms, the following patterns were revealed: the nasal mucosa is the main air conditioner of the respiratory tract and the first line of defense against infectious agents transmitted by airborne droplets. These roles require maintaining and restoring epithelial integrity and the ability to initiate immune responses. When conditions or factors are present that compromise the integrity of the mucosa, the epithelium releases alarmins and other molecular patterns associated with damage that trigger repair mechanisms but can also cause protective inflammation. In allergic rhinitis, the same mechanisms can activate the development of the disease. Many authors consider various diagnostic methods for allergic rhinitis. Such as a detailed and competent collection of complaints and anamnesis, including family history, physical examination, endoscopic examination of the nasal cavity, rhinomanometry, skin prick tests, radiological studies, including computed tomography of the paranasal sinuses, intradermal tests, study of total and specific immunoglobulins E in blood serum, basophil activation test, nasal provocation test, nasal cytology and biopsy histology, acoustic rhinometry, nasal inspiratory peak flow testing, and nitric oxide measurements are used. Attention is also paid to laboratory and instrumental methods for the differential diagnosis of rhinitis of pseudoallergic origin; the following methods are used: ultrasound diagnostics of the hepatobiliary system, biochemical blood test, and immunological studies. Treatment of patients with allergic rhinitis requires an integrated and interdisciplinary approach and, of course, requires differential and personalized methods taking into account etiopathogenetic mechanisms.

Reliability and validation of an electronic penicillin allergy risk-assessment tool in a pregnant population

BackgroundPenicillin allergy adversely impacts patient care, yet most cases do not have true allergies. Clinicians require efficient, reliable clinical tools to identify low risk patients who can be safely de-labeled. Our center implemented the FIRSTLINE electronic point-of-care decision support tool to help non-allergist practitioners risk stratify patients with penicillin allergy. We sought to explore the reliability and validity of this tool in relation to allergist assessment and actual patient outcomes. We additionally compared it with two other published stratification tools, JAMA and PENFAST, to assess ability to accurately identify low risk patients appropriate for direct oral challenge.MethodsIn this single-center, retrospective, observational study, 181 pregnant females with self-reported penicillin allergy between July 2019 to June 2021 at BC Women’s Hospital, Vancouver, Canada were used to assess the reliability and validity of all three tools. Physician-guided history of penicillin use and symptoms were used for scoring. Results and recommendations were compared to actual patient outcomes after clinician decision for direct oral challenge or intradermal tests. We compared the performance of JAMA, PENFAST and FIRSTLINE.Results181 patients were assessed. 176/181 (97.2%) patients were deemed not allergic. Each risk stratification tool labelled majority of patients as low risk with 88.4% of patients PENFAST 0–2, 60.2% of patients JAMA low risk, 86.7% of patients FIRSTLINE very low risk.ConclusionWe demonstrate that our point-of-care electronic algorithm is reliable in identifying low risk pregnant patients, as compared to an allergist assessment. To our knowledge, this is the first study to provide direct comparison between multiple decision support tools using the same population, minimizing participant bias. Providing clinical algorithms to risk stratify patients, can enable healthcare professionals to safely identify individuals who may be candidates for direct penicillin oral challenges versus needing referral to specialists. This increases the generalizability and efficiency of penicillin allergy de-labeling.

Equivalence in intradermal reactions to histamine and compound 48/80 in dogs before and after sedation with dexmedetomidine or a 1:20 combination of medetomidine and vatinoxan.

Intradermal allergen testing (IDAT) is commonly used to formulate allergen-specific immunotherapy, a pillar treatment for canine atopic dermatitis. Many sedatives have shown histaminergic or anti-histaminergic effects and thus been deemed unsuitable for IDAT. The goal of this study was to determine whether, in healthy dogs, dexmedetomidine (Dexdomitor) or a 1:20 combination of medetomidine and vatinoxan (Zenalpha) will affect intradermal reactions compared to unsedated dogs. Ten privately owned healthy dogs were enrolled in this equivalence study. Wheal formation was subjectively and objectively assessed in conscious then sedated dogs. Dogs were randomly sedated with either Dexdomitor (dexmedetomidine [0.5 mg/m2]) or Zenalpha (medetomidine [1 mg/m2/vatinoxan] 20 mg/m2) intramuscularly. Once sedated, five 10-fold histamine (100-0.01 μg/mL) and compound 48/80 (200-0.02 μg/mL) dilutions were intradermally injected into the lateral thorax. The study was repeated on the opposite side with the alternative sedation 1 week later. Quality of sedation, cardiorespiratory function and rectal temperature were recorded every 5 min. There was no difference in the median values of the reactions with either sedative when compared to unsedated dogs. Dexdomitor and Zenalpha achieved an equivalence in both subjective and objective scoring systems for all concentrations tested. A faster median time to sedation (10 vs. 18 min, p = 0.013) was seen with Zenalpha compared to Dexdomitor. Although both sedatives depressed the cardiovascular function, such parameters were less affected by Zenalpha than by Dexdomitor (p ≤ 0.001). Owing to the lack of effects on wheal formation, both sedatives are appropriate for sedating dogs undergoing IDAT. Although, such results should be validated in allergic dogs. Zenalpha may induce more rapid and reliable sedation than Dexdomitor.

Retrospective analysis of rapid drug desensitization with biologic agents: A single center experience.

Following the increased use of biological agents, a subset of patients experiences hypersensitivity reaction (HSR). We reported our experience with rapid drug desensitization (RDD) to nine biologics (rituximab, infliximab, cetuximab, trastuzumab, pertuzumab, nivolumab, brentuximab, tocilizumab and filgrastim) and identified risk factors for breakthrough reactions (BTRs). This was a retrospective review (2013-2022) of patients with immediate HSRs to biological agents. Initial HSRs were classified as grade 1, 2, or 3 in their severity. Skin prick tests (SPT)/intradermal tests (IDT) were performed using implicated agents. The phenotypes of HSRs were defined as Type I, cytokine-release syndrome (CRS), mixed reactions (cytokine-release+type I) based on history, clinical presentations and skin tests with implicated biologicals. A 12-step RDD protocol was used. The study comprised 45 patients (F/M: 31/14, median age: 55 (range: 20-69)). Majority of the patients reacted at the first infusion (n: 29/45, 64.4%). The majority of initial HSRs were grade 3 (n: 24/45, 53.3%) and grade 2 (n: 21/45, 46.6%); none were grade 1. Initial reactions were presented as type I (n: 20/45, 44.4%), CRS (n: 12/45, 26.6%) and mixed (n: 13/45, 28.8%). A total of 258 RDDs were performed and 98.4% of them were completed successfully. BTRs occurred in 36/258 (13.9%) infusions of RDDs. There was no significant association between the BTRs and age, drug cycle, SPT and IDT positivity, gender, comorbidities, or atopy. In our experience, 98.4% of 258 RDDs to biologics were successfully completed; RDD was safe and effective for our population.

Anaphylaxis induced by indocyanine green during abdominal surgery: A case report

Since 2011, indocyanine green (ICG) has been increasingly used in surgery as a diagnostic tool. Although allergic reactions to this fluorescent dye are considered rare, they can result in anaphylactic shock. We report the case of a 33-year-old woman who developed anaphylaxis immediately after ICG administration during laparoscopic-assisted high anterior resection. The patient was treated with intravenous adrenaline, and the surgery continued. Elevated plasma histamine and serum tryptase levels immediately after ICG administration and intradermal testing identified ICG as the causative agent. The frequency of ICG use is increasing, and anesthesiologists should recognize ICG as a prevalent perioperative allergen.

Anaphylactic reaction to tranexamic acid infusion in a six-year-old child: a case report

BackgroundTranexamic acid (TXA) is commonly considered a safe drug to mitigate bleeding during and after various surgical settings among adults and children. In recent decades, anaphylaxis induced by TXA has been increasingly reported in adults. However, among pediatrics, there are fewer reported cases.Case presentationWe report a case of a 6-year-old female who experienced anaphylaxis after receiving intravenous TXA following unilateral cleft lip and palate repair surgery. She exhibited clinical symptoms involving the cardiovascular system, respiratory system, and skin. Following the administration of epinephrine, corticosteroid, and anti-histamine, the patient’s symptoms were relieved. A few months after discharge, an intradermal test, yielded a positive result, confirming TXA as the culprit drug.ConclusionOur report emphasizes the importance of considering anaphylaxis as a potential adverse reaction to TXA in pediatric patients, showing the criticality of rapid diagnosis and appropriate management for a successful outcome.

Empowering Pediatricians With Direct Penicillin Challenges: A Promising Delabeling Strategy.

Current literature supports a multidisciplinary approach to penicillin allergy delabeling. Our study aims to review the success rate of penicillin challenges performed at Walter Reed National Military Medical Center Allergy Clinic and assess the reaction rate associated with a direct oral challenge in low-risk patients. We conducted a retrospective review of the outcomes of pediatric penicillin challenges at the Walter Reed National Military Medical Center Allergy and Immunology clinic from June 2019 to May 2023. A total of 74 challenges were included in this study. Patients were initially screened to assess the date of reaction, nature of reaction, if the reaction was life-threatening, and if the patient was hospitalized or sought emergency medical care for the reported reaction. After completion of the screening questionnaire, a direct graded challenge was performed (without skin testing) if a patient's history was deemed low risk. Patients with a recent reaction or a history of multiple drug allergies were more likely to be directed to skin prick testing and intra-dermal testing with Pre-pen and Penicillin-G prior to challenge. All patients passed all challenges. Thus, there was a 100% pass rate for both direct challenges and skin test with oral challenges. Given the low rate of adverse events in this study, expansion of penicillin delabeling in the primary care setting should be considered in patients deemed to be at low risk. It is important for allergists to empower and educate their peers and push forward a movement to create a multidisciplinary approach to penicillin delabeling.

Allergen Testing: A Review of the Indications, Procedures, and Limitations in Ocular Allergy.

Allergen-based diagnostics are essential in the management algorithm of allergic diseases. Unlike systemic allergy, where the indications and interpretation of these diagnostic modalities are well established, their utility in ocular allergy is not well-defined. With the rising prevalence of ocular allergies and the need for personalized treatment strategies, there is a growing demand for precision allergen diagnostics. This review describes the commonly used tests with their indications, procedures, and limitations. A review of the literature was carried out on articles on allergen diagnostics in ocular allergy, and after excluding articles that were not relevant, 82 papers were included in the current review. IgE-mediated pathways contribute significantly to seasonal and perennial ocular allergy and partly to vernal keratoconjunctivitis. Most diagnostic techniques aim to detect IgE sensitization. In vivo tests include skin prick (SPT), intradermal, and patch tests. SPT is considered the gold standard and directly evaluates the presence of allergen-specific IgE in the skin. In vitro tests measure total and specific IgE from either tears or sera. Tear IgE measurement is relatively specific for allergic conjunctivitis and can provide insight into the potential allergens responsible for local sensitization. The conjunctival provocation test can help establish true allergy, especially in patients with polysensitization. This review also provides an overview of evidence in literature segregated based on the test employed. This includes 17 studies on only SPT; 42 studies on IgE measured in serum, tears, or both; and 20 studies which have evaluated both SPT and IgE. The pattern of allergen sensitization can guide recommendations for avoidance measures and immunotherapy. Thus, this could create a corticosteroid-sparing therapy avenue in these patients, reducing disease severity and resulting visual morbidity.

COVID-19 vaccines: anaphylaxis and anxiety : Acase study from an allergy unit.

Vaccination against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) was one crucial element to overcome the coronavirus disease 2019 (COVID-19) pandemic. Even though anaphylaxis to vaccines is rare, 47patients came to the Allergy Unit at the University Hospital Graz, Austria, reporting immediate anaphylactoid symptoms after administration of COVID-19 vaccines. In addition, 29patients with known drug-induced anaphylaxis wanted to be tested for apossible sensitization against COVID-19 vaccines or excipients, such as polyethylene glycol (PEG) or polysorbate80 (PS80) before the first COVID-19 vaccination. Skin prick tests and intradermal tests were performed in all 76patients, mostly using PEG 2000, and/or PS80. Skin prick tests with COVID-19 vaccines were performed depending on availability. Our aim was to characterize this patient cohort in terms of patients' anaphylactoid responses, their willingness to future vaccinations against SARS-Cov‑2, and reasons for their decision. We developed aquestionnaire and analyzed 34completed copies. Of the 47patients with anaphylactoid reactions to COVID-19 vaccination, most were female (40female/7male). The skin tests, even when performed with the respective COVID-19 vaccine, were negative in all but one patient. Most patients who experienced anaphylactoid reactions after aCOVID-19 vaccination, did not want another COVID-19 vaccination at the time of answering the questionnaire because of anxiety for another anaphylactoid response at the next shot. Premedication with antihistamines significantly lowered (n = 74vaccinations) the severity of anaphylactoid responses after COVID-19vaccinations. Anxiety about another anaphylactoid episode hinders patients to be vaccinated against SARS-CoV‑2 again. Premedication with antihistamines and collaboration of allergologists with psychologists might lower the risk of an anaphylactic/anaphylactoid response as well anxiety in drug-induced anaphylactic patients.

Evaluating the ability of non-tuberculous mycobacteria to induce non-specific reactions in bovine tuberculosis diagnostic tests in guinea pigs and cattle

Limitations in diagnostic test performance are one of the major challenges hampering the eradication of bovine tuberculosis (bTB). Non-tuberculous mycobacteria (NTM) are considered one of the main causes of non-specific reactions in the intradermal tuberculin test, the most widely used bTB diagnostic test. To determine the role of NTMs in bTB misdiagnosis in Spain, an experimental study including the NTM species most commonly found in bTB-positive animals from bTB-free farms in the country (M. avium subsp. avium (Maa), “Mycobacterium avium subsp. hominissuis” (Mah), M. bourgelatii, M. intermedium, M. kansasii and M. nonchromogenicum) was carried out on guinea pigs and cattle. First, guinea pigs were sensitized with the selected NTMs, and six weeks post-sensitization four antigen mixtures (bovine-PPD, avian-PPD, P22 and ESAT6-CFP10) were inoculated intradermally and their effect was measured 24- and 48-h post-inoculation. Larger erythematous reactions were observed in guinea pigs sensitized with Mah, M. kansasii, and Maa, with significant differences in the reactions measured at the bovine-PPD inoculation site for the two first bacteria compared with other NTMs. The sensitization process was repeated in cattle, and five months post-sensitization the same antigen mixtures were inoculated in the cervical region and responses were measured at 48- and 72-h post-inoculation. A significantly higher increase in the skinfold thickness measured at the bovine-PPD inoculation site was observed in calves sensitized with Mah, Maa, M. intermedium and M. kansasii. These results demonstrate that certain NTM species may play a more significant role in bTB diagnostic interferences and show that results obtained in guinea pig and bovine models do not always coincide.

Clinical diagnosis of chronic mucocutaneous candidiasis in a patient with recurrent staphylococcal infections

Chronic mucocutaneous candidiasis is a primary immunodeficiency characterized by persistent or recurrent candidal infections of the skin, nails, or mucous membranes. It can be associated with endocrinopathies and autoimmune diseases. A 37-years-old male patient is presented who attended an immunology consultation referred from the dermatology service due to recurrent pyodermitis of several years of evolution; the physical examination also revealed signs of candidiasis in the oral mucosa and lip corners, in the eyelids of both eyes and skin in the abdominal region, which were recurrent, as well as onychomycosis in all toenails. The microbiological study of the pyodermitis lesions showed infection by staphylococcus aureus, and the lesions of the mouth, eyes, abdominal skin and nails showed the presence of Candida albicans. Delayed intradermal skin testing was performed with no T cell response to Candida and Trichophyton antigens. Complementary drugs were indicated to rule out any associated endocrine disorder

An Evaluation of Skin and Immunological Responses after Using a Novel Cross-Linked Porcine-Based Dermal Injectable Collagen with Lidocaine for Nasolabial Fold Correction.

Background: Hypersensitivity to the new dermal injectable porcine-based collagen with lidocaine featuring a novel cross-linking technology (test filler) for nasolabial fold correction was compared to the commercially available traditional cross-linked dermal injectable porcine-based collagen with lidocaine (control filler). Methods: Recruited participants (n = 279) received a single 0.1 mL intradermal injection of either test filler or control filler in the left forearm as a screening skin allergy test. Injection sites were assessed clinically at 24 h post-implant. Treatment was given to 252 successfully screened participants, and injection sites were monitored for 21 days. Immunological examinations were performed at screening and then at 4 and 24 weeks post-treatment. Observations for adverse events continued until the 52nd week. Results: Intradermal allergy testing results were negative for all the test recipients (0/124) and positive for two control recipients (2/132, 1.5%). Most of the participants exhibited no changes in serum immunoglobulin (IgG, IgM) and complement (C3, C4) levels. No serious adverse events related to the device were recorded. Most adverse events were common complications of dermal filler treatment and were related to the injection site. Most adverse effects were resolved or under control by 52 weeks. Conclusions: Hypersensitivity reactions with the test filler were lower than those with the control filler, validating the safe use of test filler for nasolabial fold correction without the need for pretreatment skin testing.

Evaluation of a Novel Automated Allergy Intradermal Skin Test Reader: A Diagnostic Accuracy Study.

Evaluation of a Novel Automated Allergy Intradermal Skin Test Reader: A Diagnostic Accuracy Study.

No Yellow Fever Vaccine Reactions in IgE-Mediated Egg Allergic Patients

Introduction: Egg allergy usually manifests during the initial 2 years of life, a period in which most vaccinations are administered. This often leads to delays in the application of some vaccines in patients with egg allergies, exposing them to a risk of contracting preventable infections. The aim of the study was to describe the frequency of reactions after applying the yellow fever vaccine (YFV) within a population with egg allergy. Methods: This was a cohort study with retrospective, multicenter data (2014–2023). Patient records diagnosed with egg allergy were gathered from their initial egg-related reactions until their YFV administration. Information was also collected about hypersensitivity tests conducted for egg and YFV such as the skin prick test (SPT) and intradermal test (IDT). Results: Among the 171 records analyzed, 23.9% of patients had a history of egg anaphylaxis. Out of these, 5 patients had a positive SPT and 21 IDT with the YFV. All patients tolerated the application of YFV without developing hypersensitivity reactions, regardless of the results of the YFV tests, the severity of egg reactions, the number of egg reactions, or the time since the last egg reaction. Out of the total patient cohort, 46.1% (79 individuals) encountered delays in receiving the YFV, and in this subset, 14% faced delays lasting longer than 12 months. Conclusion: The risk of allergic reactions with the YFV remains low. YFV tests generate delays in the vaccine application without providing high diagnostic accuracy. YFV should not be deferred even in patients with a history of severe egg reactions.

Causative agent for perioperative anaphylaxis in a child with autism successfully identified using the intradermal test under general anesthesia

BackgroundThe skin-prick and intradermal tests are the main diagnostic methods used to identify the causative agent in patients with suspected perioperative anaphylaxis. Although the intradermal test is more sensitive than the skin-prick test, multiple intradermal injections can be painful for children. Here, we present the case of a child with autism and suspected perioperative anaphylaxis. The causative agent was successfully identified using the intradermal test under general anesthesia.Case presentationAn 8-year-old boy with autism developed anaphylaxis during general anesthesia for the fourth cleft lip and palate surgery. An allergic workout was performed, but both the skin-prick and basophil activation tests for suspected causative agents yielded negative results. The patient was afraid of multiple injections, and an intradermal test was performed under general anesthesia by anesthesiologists and allergists. Piperacillin was confirmed as the causative agent, and subsequent surgery using the same anesthetic agents without piperacillin was uneventful.ConclusionsConcerted efforts should be made to identify the causative agent for diagnosing perioperative anaphylaxis.

Bullous Drug Eruption.

A 63-year-old woman presented at our emergency department with a disseminated dermatosis that developed after undergoing a cardiac catheterization procedure. Her past medical history included an end-stage renal disease undergoing hemodialysis. Clinical examination revealed erosions and hemorrhagic crusts located on her lips and along the arteriovenous fistula. Additionally, we observed five hyperpigmented macules on her left hand's dorsum and palm and multiple hypopigmented macules in the genital area. Upon medical record review, we discovered the occurrence of prior bullous eruptions following contrast administration. A fixed drug eruption (FDE) due to radiocontrast was diagnosed based on clinical history, clinical examination, eruption timeframe, and positive drug provocation test. Intravenous contrast media reactions can be immediate or delayed, with delayed hypersensitivity reactions (DHR) occurring one hour to seven days post-administration. DHRs often present as maculopapular rashes. FDEs are rare. Skin tests are used to identify culprit agents. Ideally, intradermal tests, with delayed readings, and patch tests are combined for optimal sensitivity. Despite lacking standardized protocols, premedication with corticosteroids may mitigate reaction severity.

Extensive differential DNA methylation between tuberculosis skin test positive and skin test negative cattle

Bovine tuberculosis (bTB), caused by Mycobacterium bovis (M. bovis), represents a significant problem for the agriculture industry as well as posing a risk for human health. Current diagnostic tests for bTB target the cell-mediated immune (CMI) response to infection with M. bovis, primarily through screening of animals with the tuberculin skin test. Epigenetic modifications have been shown to alter the course of the immune response and differentially methylated regions (DMRs) might also influence the outcome of the skin test in cattle. Whole Genome Bisulphite Sequencing (WGBS) was used to profile DNA methylation levels from peripheral blood of a group of cattle identified as test positive for M. bovis (positive for the single intradermal comparative tuberculin test (SICTT) and/or the interferon-γ release assay compared to a test negative control group [n = 8/group, total of 16 WGBS libraries]. Although global methylation profiles were similar for both groups across the genome, 223 DMRs and 159 Differentially Promoter Methylated Genes (DPMGs) were identified between groups with an excess of hypermethylated sites in SICTT positive cattle (threshold > 15% differential methylation). Genes located within these DMRs included the Interleukin 1 receptor (IL1R1) and MHC related genes (BOLA and BOLA-DQB). KEGG pathway analysis identified enrichment of genes involved in Calcium and MAPK signalling, as well as metabolism pathways. Analysis of DMRs in a subset of SICTT negative cattle that were IFN-γ positive showed differential methylation of genes including Interleukin 10 Receptor, alpha (IL10RA), Interleukin 17 F (IL17F) and host defence peptides (DEFB and BDEF109). This study has identified a number of immune gene loci at which differential methylation is associated with SICTT test results and the degree of methylation could influence effective host immune responses.

Novel collagen gradient membranes with multiphasic structures: Preparation, characterization, and biocompatibility

Scaffolds with multiphasic structures are considered to be superior for guided tissue regeneration. Two types of tilapia skin collagen gradient membranes (stepped gradient and linear gradient) with multiphasic structures were prepared by controlling the collagen concentrations and the freezing rates. The results revealed that collagen gradient membranes were more capable of guiding tissue regeneration compared to homogeneous membranes. These two gradient membranes featured a dense outer layer and a loose inner layer, with good mechanical properties as indicated by tensile strengths of more than 250 Kpa and porosities exceeding 85 %. Additionally, these membranes also showed good hydrophilicity and water absorption, with an inner layer contact angle of less than 91° and a water absorption ratio greater than 40 times. Furthermore, the multiphasic scaffolds were proved to be biocompatible by the acute toxicity assay, the intradermal irritation test and so on. Gradient membranes could effectively promote the adhesion and proliferation of fibroblasts and osteoblasts, through elevating the TGF-β/Smad signaling pathway by TGF-β and Smads, and activating the Wnt/β-catenin signaling pathway by LRP5 and β-catenin, similar to homogenous membranes. Therefore, collagen gradient membranes from tilapia skin show important application value in guiding tissue regeneration.

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

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

Comparing Skin and Serum Testing to Direct Challenge Outcomes in Children With β-Lactam Allergies

BackgroundThere is a scarcity of prospective studies investigating the relative roles of skin prick and intradermal testing, serum-specific Immunoglobulin E, and extended oral challenges in diagnosing children with reported beta-lactam allergies. ObjectiveTo determine the sensitivity and specificity of skin testing and serum-specific Immunoglobulin E in children with beta-lactam allergies, with immediate and non-immediate historic reactions. MethodsFour hundred children with parent-reported beta-lactam allergies were recruited into an open-label prospective study. Detailed allergy histories were collected. Those with medically observed and documented histories of anaphylaxis, requiring epinephrine, or SCARs were excluded. In total, 380 children underwent all testing modalities and a direct provocation test. Each child was followed up for a minimum of three years. ResultsTrue allergy in children was uncommon, 8·3% reacted to the direct provocation challenge or the 5-day extended oral provocation challenge. Children reporting cephalosporin allergy or a reaction within one year were more likely to react to direct provocation testing. The sensitivity, specificity, and positive predictive value of skin testing was 12·5%, 98·8% and 20·0% for direct challenge outcomes, 4·76%, 99·0% and 25·0% for extended challenge outcomes, and 6·9%, 99·0% and 40·0% for both challenges combined. Follow-up investigations revealed that 5·7% of children had a mild repeat reaction and 2·7% continued to avoid the culprit despite successful delabeling. The relabeling rate for children readmitted to hospital was 15% with the relabeing being unfounded. ConclusionGenuine beta-lactam allergies were rare, with over 90% of children effectively delabeled. Skin and serum-specific Immunoglobulin E testing did not aid the diagnosis of beta-lactam antibiotic allergy in children, regardless of medical history. Extended oral challenges proved valuable in confirming allergies and boosted parental confidence.