Dupilumab in patients with chronic spontaneous urticaria (LIBERTY-CSU CUPID): Two randomized, double-blind, placebo-controlled, phase 3 trials.

BACKGROUND: Chronic spontaneous urticaria (CSU) is a chronic inflammatory disease characterized by recurrent pruritic wheals (hives) and/or angioedema. Patients with CSU could remain symptomatic despite standard-of-care H1 antihistamines (H1-AH) or anti-IgE (omalizumab) treatment. Dupilumab blocks IL-4/IL-13 signaling and is approved for multiple type 2/atopic indications. OBJECTIVE: We conducted two phase 3, randomized, placebo-controlled, double-blind trials comparing dupilumab with placebo in patients with symptomatic CSU despite H1-AH. METHODS: In LIBERTY-CSU CUPID Study A, patients were omalizumab-naive (n = 138, aged ≥6 years). In Study B, patients were omalizumab-intolerant/incomplete responders (n = 108, aged ≥12 years). The primary end point was either change from baseline over 7 days in the Urticaria Activity Score (UAS7) or Itch Severity Score (ISS7) at week 24, with the other as a key secondary end point, depending on regional regulatory requirements. Studies were pooled for safety assessment. RESULTS: In Study A, UAS7 and ISS7 improved with dupilumab versus placebo (difference -8.5 [95% CI, -13.2 to -3.9; P = .0003] and -4.2 [95% CI, -6.6 to -1.8; P = .0005]). In Study B, tested at α = 0.043 after interim analysis, UAS7 improved (difference -5.8 [95% CI, -11.4 to -0.3; P = .0390]), with a numerical trend in ISS7 (difference -2.9 [95% CI, -5.7 to -0.07; nominal P = .0449, not significant]). Pooled safety data were consistent between dupilumab and placebo and with the known dupilumab safety profile. CONCLUSIONS: Dupilumab reduced urticaria activity by reducing itch and hives severity in omalizumab-naive patients with CSU uncontrolled with H1-AH. Although the primary end point for Study B was not met, dupilumab effects were small in patients who were omalizumab-intolerant/incomplete responders.

Leukotriene receptor antagonists as add-on therapy to antihistamines for urticaria: Systematic review and meta-analysis of randomized clinical trials.

BACKGROUND: The benefits and harms of adding antileukotrienes to H1 antihistamines (AHs) for the management of urticaria (hives, itch, and/or angioedema) remain unclear. OBJECTIVE: We sought to systematically synthesize the treatment outcomes of antileukotrienes in combination with AHs versus AHs alone for acute and chronic urticaria. METHODS: As part of updating American Academy of Allergy, Asthma & Immunology and American College of Allergy, Asthma, and Immunology Joint Task Force on Practice Parameters urticaria guidelines, we searched Medline, Embase, Central, LILACS, WPRIM, IBECS, ICTRP, CBM, CNKI, VIP, Wanfang, US Food and Drug Administration, and European Medicines Agency databases from inception to December 18, 2023, for randomized controlled trials (RCTs) evaluating antileukotrienes and AHs versus AHs alone in patients with urticaria. Paired reviewers independently screened citations, extracted data, and assessed risk of bias. Random effects models pooled effect estimates for urticaria activity, itch, wheal, sleep, quality of life, and harms. The GRADE approach informed certainty of evidence ratings. The study was registered at the Open Science Framework (osf.io/h2bfx/). RESULTS: Thirty-four RCTs enrolled 3324 children and adults. Compared to AHs alone, the combination of a leukotriene receptor antagonist with AHs probably modestly reduces urticaria activity (mean difference, -5.04; 95% confidence interval, -6.36 to -3.71; 7-day urticaria activity score) with moderate certainty. We made similar findings for itch and wheal severity as well as quality of life. Adverse events were probably not different between groups (moderate certainty); however, no RCT reported on neuropsychiatric adverse events. CONCLUSION: Among patients with urticaria, adding leukotriene receptor antagonists to AHs probably modestly improves urticaria activity with little to no increase in overall adverse events. The added risk of neuropsychiatric adverse events in this population with leukotriene receptor antagonists is small and uncertain.

Clinical characteristics and management of pediatric egg-induced anaphylaxis: A cross-sectional study.

BACKGROUND: Egg is the third most common food allergy in children; however, data on pediatric egg-induced anaphylaxis are sparse. OBJECTIVE: To describe the clinical characteristics, management, and outcomes of pediatric egg-induced anaphylaxis. METHODS: Children presenting with anaphylaxis were recruited from 13 emergency departments as part of the Cross-Canada Anaphylaxis Registry, from which data on anaphylaxis triggered by egg were extracted. Multivariate logistic regression was used to determine factors associated with prehospital epinephrine autoinjector (EAI) use and to compare anaphylaxis triggered by egg with other triggers of food-induced anaphylaxis (FIA). RESULTS: We recruited 302 children with egg-induced anaphylaxis. The mean age was 2.6 years (SD = 3.6), and 55.3% were male. Only 39.4% had previously been diagnosed with an egg allergy. Prehospital EAI use was 32.1%, but this was not significantly lower than in other triggers of FIA (P = .26). Only 1.4% of patients required hospital admission. Relative to other triggers of FIA, patients with egg-induced anaphylaxis were significantly younger (P < .001) and exhibited more vomiting (P = .0053) and less throat tightness (P = .0015) and angioedema (P < .001). CONCLUSION: To the best of our knowledge, this is the largest published cohort of pediatric egg-induced anaphylaxis. In this cohort, prehospital EAI use was very low. In addition, we identified certain symptoms that distinguish egg-induced from other triggers of FIA. Taken together, high suspicion is crucial in identifying egg-induced anaphylaxis, given the younger patient demographic and frequent lack of FIA history.

Milk-induced anaphylaxis among children presenting to Canadian emergency departments.

BACKGROUND: Cow's milk is one of the most common and burdensome allergens in pediatrics, and it can induce severe anaphylactic reactions in children. However, data on cow's milk-induced anaphylaxis are sparse. OBJECTIVE: To describe the epidemiology of pediatric cow's milk-induced anaphylaxis and to determine risk factors for repeat emergency department (ED) epinephrine administration. METHODS: Between April 2011 and May 2023, data were collected on children with anaphylaxis presenting to 10 Canadian EDs. A standardized form documenting symptoms, triggers, treatment, and outcome was used. Multivariate logistic regression was used. RESULTS: Of 3118 anaphylactic reactions, 319 milk-induced anaphylaxis cases were identified (10%). In the prehospital setting, 54% of patients with milk-induced anaphylaxis received intramuscular epinephrine. In those with milk-induced anaphylaxis, receiving epinephrine before presenting to the ED was associated with a reduced risk of requiring 2 or more epinephrine doses in the ED (adjusted odds ratio, 0.95 [95% CI, 0.90-0.99]). Children younger than 5 years of age were more likely to experience a mild reaction compared with that in older children, who experienced a moderate reaction more often (P < .0001). Compared with other forms of food-induced anaphylaxis, children presenting with milk-induced anaphylaxis were younger; a greater proportion experienced wheezing and vomiting, and less experienced angioedema. CONCLUSION: Prehospital epinephrine in pediatric milk-induced anaphylaxis is underused; however, it may decrease risk of requiring 2 ED epinephrine doses. Milk-induced anaphylaxis in children younger than 5 years of age may be less severe than in older children. Wheezing and vomiting are more prevalent in milk-induced anaphylaxis compared with that of other foods.

Topical corticosteroids for hives and itch (urticaria): Systematic review and Bayesian meta-analysis of randomized trials.

BACKGROUND: Topical corticosteroids are widely used as a treatment for itch and wheals (urticaria), but their benefits and harms are unclear. OBJECTIVE: To systematically synthesize the benefits and harms of topical corticosteroids for the treatment of urticaria. METHODS: We searched MEDLINE, EMBASE, and CENTRAL from database inception to March 23, 2024, for randomized trials comparing topical corticosteroids with placebo for patients with urticaria (either chronic spontaneous or inducible urticaria or acute urticaria elicited from skin/intradermal allergy testing). Paired reviewers independently screened records, extracted data, and assessed risk of bias. Random-effects meta-analyses addressed urticaria severity, itch severity (numeric rating scale; range 0-10; higher is worse), and adverse events. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach informed certainty of evidence ratings. PROSPERO registration: CRD42023455182. RESULTS: A total of 19 randomized controlled trials enrolled 379 participants with a median of mean age of 30.1 (range 21.1-44.0) years. Compared with placebo, topical corticosteroids may reduce wheal size (ratio of means 0.47, 95% CI 0.38-0.59; low certainty) and itch severity (mean difference -1.30, 95% CI -5.07 to 2.46; very low certainty). Topical corticosteroids result in little to no difference in overall adverse events (94 fewer patients per 1000, 95% credible intervals 172 fewer to 12 more; high certainty). CONCLUSION: Compared with placebo, topical corticosteroids may result in a reduction of wheal size and little to no difference in overall adverse events. Topical corticosteroids may reduce itch severity, but the evidence is very uncertain. Future large, randomized trials addressing the use of topical corticosteroids would further support optimal urticaria management.

Prevalence of omalizumab resistant chronic urticaria and real world effectiveness of dupilumab in omalizumab refractory chronic urticaria patients: a single center experience.

Chronic urticaria (CU) is characterized by wheals, angioedema, or both lasting for ≥ 6 weeks with chronic spontaneous urticaria (CSU) being the most common subtype. Omalizumab-resistant CSU cases represent an unmet clinical need. In this study, we aimed to assess the prevalence and predictors of omalizumab failure in a large cohort of CU patients and assess the effectiveness of dupilumab for omalizumab-recalcitrant CU. Of 338 CU patients, 33 received omalizumab. 69.7% (23 patients) were responders and 30.3% (10 patients) non-responders. Bivariate regression demonstrated that female sex (adjusted OR [aOR] = 1.53; 95%CI = 1.14-2.06), higher baseline UAS7 (aOR = 1.05; 95%CI = 1.01-1.09) and older age (controlling for sex) (aOR = 1.00; 95%CI = 1.00, 1.01) were associated with omalizumab failure. Of 10 omalizumab-refractory patients, three were well controlled with cyclosporine (all children), whereas the seven adults failed on average 5.6 ± 2.6 therapies including cyclosporine. All 7 achieved a complete response with dupilumab with time to response varying between 1 to 6 months. While our results suggest a favourable efficacy of dupilumab omalizumab-resistant cases, future confirmatory studies are required.

Cold-induced anaphylaxis triggered by drinking cold water.

Cold urticaria is an inducible urticaria in which hives and angioedema appear after exposure to cold. The symptoms of cold urticaria often are limited to hives/angioedema. However, in up to 20% of cases, cold exposure may trigger anaphylaxis. We report the case of an 11-year-old boy previously diagnosed with chronic spontaneous urticaria who developed facial swelling, itchy hives, difficulty in breathing, vomiting and abdominal pain within 5 minutes of drinking cold water. He received a standard dose of non-sedating second-generation antihistamines at home. He was observed in the emergency room for 2 hours and discharged with an epinephrin autoinjector. During the subsequent outpatient clinic visit, an ice cube test was performed which confirmed the new diagnosis of comorbid cold-induced chronic urticaria. On further questioning, the parents reported occurrence of hives following swimming in the swimming pool. Cold-induced urticaria should be suspected in cases of anaphylaxis associated with cold exposure. Patients with chronic forms of urticaria who present with new anaphylaxis should be assessed for a potential concomitant cold-induced form.

Updated guidance regarding the risk of allergic reactions to COVID-19 vaccines and recommended evaluation and management: A GRADE assessment and international consensus approach.

This guidance updates 2021 GRADE (Grading of Recommendations Assessment, Development and Evaluation) recommendations regarding immediate allergic reactions following coronavirus disease 2019 (COVID-19) vaccines and addresses revaccinating individuals with first-dose allergic reactions and allergy testing to determine revaccination outcomes. Recent meta-analyses assessed the incidence of severe allergic reactions to initial COVID-19 vaccination, risk of mRNA-COVID-19 revaccination after an initial reaction, and diagnostic accuracy of COVID-19 vaccine and vaccine excipient testing in predicting reactions. GRADE methods informed rating the certainty of evidence and strength of recommendations. A modified Delphi panel consisting of experts in allergy, anaphylaxis, vaccinology, infectious diseases, emergency medicine, and primary care from Australia, Canada, Europe, Japan, South Africa, the United Kingdom, and the United States formed the recommendations. We recommend vaccination for persons without COVID-19 vaccine excipient allergy and revaccination after a prior immediate allergic reaction. We suggest against >15-minute postvaccination observation. We recommend against mRNA vaccine or excipient skin testing to predict outcomes. We suggest revaccination of persons with an immediate allergic reaction to the mRNA vaccine or excipients be performed by a person with vaccine allergy expertise in a properly equipped setting. We suggest against premedication, split-dosing, or special precautions because of a comorbid allergic history.

A Systematic Review of Food Protein-Induced Enterocolitis Syndrome.

Food protein-induced enterocolitis syndrome (FPIES) is a non-IgE-mediated gastrointestinal food-induced hypersensitivity disorder that occurs mostly in infants. Long considered a rare disease, a recent increase in physician awareness and publication of diagnosis of guidelines has resulted in an increase in recognized FPIES cases. We aimed to conduct a systematic review of FPIES studies in the past 10 years. A search was conducted on PubMed and Embase in March 2022. Our systematic review focused on 2 domains: (1) the most reported FPIES food triggers; and (2) the resolution rate and median age at resolution of patients with FPIES. We found that cow's milk was the most reported trigger globally. Patterns of the most common triggers varied by country, with fish being one of the most common triggers in the Mediterranean region. We also found that the rate and median age of resolution varied by trigger. Patients with FPIES to cow's milk acquired tolerance at a younger age (most by age 3 years), while fish-FPIES was more persistent (mean resolution by age 37 months-7 years). Overall, many studies found a resolution rate of 60% for any food.

Ligelizumab in adolescents with chronic spontaneous urticaria: Results of a dedicated phase 2b randomized clinical trial supported with pharmacometric analysis.

BACKGROUND: Chronic spontaneous urticaria (CSU), a long-lasting disease in children, impacts their quality of life. We report the results of a phase 2b dose-finding trial of ligelizumab (NCT03437278) and a high-affinity humanized monoclonal anti-IgE antibody, in adolescents with CSU, supported by modeling and simulation analyses, mitigating challenges in pediatric drug development. METHODS: This multicenter, double-blind, placebo-controlled trial, randomized H1-antihistamine-refractory adolescent CSU patients (12-18 years) 2:1:1 to ligelizumab 24 mg, 120 mg, or placebo every 4 weeks for 24 weeks. Patients on placebo transitioned to ligelizumab 120 mg at week 12. Integrating data from the previous adult and present adolescent trial of ligelizumab, a nonlinear mixed-effects modeling described the longitudinal changes in ligelizumab pharmacokinetics, and its effect on weekly Urticaria Activity Score (UAS7). RESULTS: Baseline UAS7 (mean ± SD) was 30.5 ± 7.3 (n = 24), 29.3 ± 7.7 (n = 13), and 32.5 ± 9.0 (n = 12) for patients (median age, 15 years) on ligelizumab 24 mg, 120 mg, and placebo, respectively. Change from baseline in UAS7 at week 12 with ligelizumab 24 mg, 120 mg, and placebo was -15.7 ± 10.9, -18.4 ± 12.3, and -13.0 ± 13.0, respectively. Ligelizumab was well-tolerated. The modeling analysis showed that body weight, but not age, affected ligelizumab's apparent clearance. No significant differences between adolescents and adults were detected on the model-estimated maximum effect and potency. CONCLUSIONS: Ligelizumab exhibited efficacy and safety in adolescent CSU patients, consistent with that in adults. The PK and potency of ligelizumab were not impacted by age, and the same dose of ligelizumab can be used for treating adolescents and adults with CSU. Our study shows how modeling and simulation can complement pediatric drug development.

Prehospital epinephrine administration for treating anaphylaxis among those with comorbid asthma: A scoping review.

BACKGROUND: Prompt and correct use of epinephrine for treating anaphylaxis is considered essential in reducing the risk of fatal outcomes from anaphylaxis. Nevertheless, prehospital use of epinephrine remains low. Although asthma is a common comorbidity in individuals experiencing severe allergic reactions, little attention has been given to whether asthma functions as a predictor of prehospital epinephrine administration. OBJECTIVE: To perform a scoping review of the extant literature on using epinephrine to manage anaphylaxis in patients with comorbid asthma before presenting to the emergency department. METHODS: Per Preferred Reporting Items for Systematic Reviews and Meta-Analyses Scoping Review guidelines, peer-reviewed articles published in English or French were searched for within the Medline, Cumulative Index to Nursing and Allied Health Literature, and Embase databases between June 11 and June 18, 2021. We excluded studies that did not contain primary data. RESULTS: The literature search yielded 1022 articles that were screened at the title and abstract level by 2 independent reviewers. Of these, 90 (8.8%) advanced to full-text review, and ultimately, 8 studies (0.8% of all articles; 8.9% of full-text articles) were included in the analysis. Overall, the association between comorbid asthma and epinephrine use in the prehospital setting for managing anaphylaxis was inconsistently reported in the literature. Three studies reported a positive association, whereas 2 others suggested a link, but their results were no longer significant when controlling for other study variables. Three studies described no significant association. CONCLUSION: Although asthma is frequently comorbid in individuals experiencing anaphylaxis, the association between comorbid asthma and prehospital epinephrine treatment rates remains an understudied area of patient care.

Managing anaphylaxis: Epinephrine, antihistamines, and corticosteroids: More than 10 years of Cross-Canada Anaphylaxis REgistry data.

BACKGROUND: Epinephrine is the first-line treatment for anaphylaxis but is often replaced with antihistamines or corticosteroids. Delayed epinephrine administration is a risk factor for fatal anaphylaxis. Convincing data on the role of antihistamines and corticosteroids in anaphylaxis management are sparse. OBJECTIVE: To establish the impact of prehospital treatment with epinephrine, antihistamines, and/or corticosteroids on anaphylaxis management. METHODS: Patients presenting with anaphylaxis were recruited prospectively and retrospectively in 10 Canadian and 1 Israeli emergency departments (EDs) between April 2011 and August 2022, as part of the Cross-Canada Anaphylaxis REgistry. Data on anaphylaxis cases were collected using a standardized form. Primary outcomes were uncontrolled reactions (>2 doses of epinephrine in ED), no prehospital epinephrine use, use of intravenous fluids in ED, and hospital admission. Multivariate regression was used to identify factors associated with primary outcomes. RESULTS: Among 5364 reactions recorded, median age was 8.8 years (IQR, 3.78-16.9); 54.9% of the patients were males, and 52.5% had a known food allergy. In the prehospital setting, 37.9% received epinephrine; 44.3% received antihistamines, and 3.15% received corticosteroids. Uncontrolled reactions happened in 250 reactions. Patients treated with prehospital epinephrine were less likely to have uncontrolled reactions (adjusted odds ratio [aOR], 0.955 [95% CI, 0.943-0.967]), receive intravenous fluids in ED (aOR, 0.976 [95% CI, 0.959-0.992]), and to be admitted after the reaction (aOR, 0.964 [95% CI, 0.949-0.980]). Patients treated with prehospital antihistamines were less likely to have uncontrolled reactions (aOR, 0.978 [95% CI, 0.967-0.989]) and to be admitted after the reaction (aOR, 0.963 [95% CI, 0.949-0.977]). Patients who received prehospital corticosteroids were more likely to require intravenous fluids in ED (aOR, 1.059 [95% CI, 1.013-1.107]) and be admitted (aOR, 1.232 [95% CI, 1.181-1.286]). CONCLUSION: Our findings in this predominantly pediatric population support the early use of epinephrine and suggest a beneficial effect of antihistamines. Corticosteroid use in anaphylaxis should be revisited.

Bridging knowledge gaps in paediatric chronic urticaria through a video-based educational tool.

BACKGROUND: There is a lack of patient educational resources about chronic urticaria (CU). AIMS: To develop and test the effectiveness of an education tool to help paediatric patients and their families better understand CU and its management. METHODS: From July 2020 to May 2022, paediatric patients with a history of CU who presented to the allergy outpatient clinics at our institution were recruited. Consenting families and patients were asked to complete five questions related to the definition, causes and management of CU at the time of presentation to the clinic. Participants were shown a 5-min animated video addressing the main knowledge gaps about CU. At the end of the video, participants were redirected to the same five questions to respond again. The scores were recorded as a proportion of correct answers (range 0·0-1·0). RESULTS: In total, 53 patients [30 girls (56·6%), 23 boys (43·4%); mean age 9·7 ± 5·1 years, range 1·4-18·5 years] were recruited. The mean baseline pre-video education questionnaire score was 0·67 ± 0·2 (range 0·2-1·0), while the mean post-video score was 0·94 ± 0·1 (range 0·4-1·0), a mean score difference of 0·27, which was statistically significant (P < 0·001). At the 1-year follow-up, 14 (26·4%) patients answered the questionnaire again to assess retention of knowledge; the mean score was 0·83 ± 0·2 (range 0·2-1·0). CONCLUSIONS: Our educational video was successful in educating patients and their families to better understand urticaria. Future studies should aim to optimize patient education through nontraditional tools such as videos, and compare knowledge gain using different methods of education.

The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria.

This update and revision of the international guideline for urticaria was developed following the methods recommended by Cochrane and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) working group. It is a joint initiative of the Dermatology Section of the European Academy of Allergology and Clinical Immunology (EAACI), the Global Allergy and Asthma European Network (GA²LEN) and its Urticaria and Angioedema Centers of Reference and Excellence (UCAREs and ACAREs), the European Dermatology Forum (EDF; EuroGuiDerm), and the Asia Pacific Association of Allergy, Asthma and Clinical Immunology with the participation of 64 delegates of 50 national and international societies and from 31 countries. The consensus conference was held on 3 December 2020. This guideline was acknowledged and accepted by the European Union of Medical Specialists (UEMS). Urticaria is a frequent, mast cell-driven disease that presents with wheals, angioedema, or both. The lifetime prevalence for acute urticaria is approximately 20%. Chronic spontaneous or inducible urticaria is disabling, impairs quality of life, and affects performance at work and school. This updated version of the international guideline for urticaria covers the definition and classification of urticaria and outlines expert-guided and evidence-based diagnostic and therapeutic approaches for the different subtypes of urticaria.

Cold urticaria in a pediatric cohort: Clinical characteristics, management, and natural history.

BACKGROUND: Cold urticaria (coldU) is associated with substantial morbidity and risk of fatality. Data on coldU in children are sparse. We aimed to evaluate the clinical characteristics, management, risk of associated anaphylaxis, and resolution rate of coldU in a pediatric cohort. Additionally, we sought to compare these metrics to children with chronic spontaneous urticaria (CSU). METHODS: We prospectively enrolled children with coldU from 2013-2021 in a cohort study at the Montreal Children's Hospital and an affiliated allergy clinic. Data for comparison with participants with solely CSU were extracted from a previous study. Data on demographics, comorbidities, severity of presentation, management, and laboratory values were collected at study entry. Patients were contacted yearly to assess for resolution. RESULTS: Fifty-two children with cold urticaria were recruited, 51.9% were female and the median age of symptom onset was 9.5 years. Most patients were managed with second-generation H1-antihistamines (sgAHs). Well-controlled disease on sgAHs was negatively associated with concomitant CSU (adjusted odds ratio (aOR) = 0.69 [95%CI: 0.53, 0.92]). Elevated eosinophils were associated with cold-induced anaphylaxis (coldA; aOR = 1.38 [95%CI: 1.04, 1.83]), which occurred in 17.3% of patients. The resolution rate of coldU was 4.8 per 100 patient-years, which was lower than that of CSU (adjusted hazard ratio = 0.43 [95%CI: 0.21, 0.89], p < 10-2 ). CONCLUSION: Pediatric coldU bears a substantial risk of anaphylaxis and a low-resolution rate. Absolute eosinophil count and co-existing CSU may be useful predictive factors.

Allergic reactions to the coronavirus disease 2019 vaccine (ARCOV) study: The McGill University Health Centre experience.

BACKGROUND: Messenger RNA coronavirus disease 2019 (COVID-19) vaccines have been associated with allergic reactions. A history of anaphylaxis has been suggested as a risk factor for such reactions. Polyethylene glycol (PEG) has been proposed as a possible culprit allergen. OBJECTIVE: To investigate possible PEG or polysorbate allergy among patients reporting prior reactions to COVID-19 vaccines or PEG and to report their subsequent tolerance of COVID-19 vaccines. METHODS: From January 1, 2021, to October 31, 2021, adult patients referred to the McGill University Health Centre allergy clinics who were considered at risk of anaphylaxis were prospectively recruited. The entry criteria were any documented history of reaction to a COVID-19 vaccine or reported allergy to PEG or polysorbate. Evaluated patients underwent skin prick testing (SPT) with PEG and polysorbate. After SPT, placebo-controlled vaccine challenges were carried out. RESULTS: Of the 44 patients recruited, 40 (90.1%) had reacted to the first vaccine dose, with 18 (45%) of them had anaphylactic reaction. All patients underwent SPT and 5 (11.3%) had a positive test result. A total of 39 patients (88.6%) underwent COVID-19 vaccine challenge at the allergy clinic. Most tolerated the vaccine, with 18 (40.1%) received a single full dose, 20 (45.4%) 2 split doses, and 6 (13.6%) a graded dosing protocol. Of the 40 patients who reacted to the first dose, 2 had immediate nonsevere allergic reactions to the second dose. CONCLUSION: In this cohort of patients with a history of anaphylaxis and increased risk of allergic reactions to the COVID-19 vaccines, after allergist evaluation, including negative PEG skin testing result, the vaccine was safely administered without any serious adverse events.

Economic burden of food allergy in Canada: Estimating costs and identifying determinants.

BACKGROUND: Limited data exist on the economic burden of food allergy (FA). OBJECTIVE: To assess FA-related direct (healthcare and out-of-pocket) and indirect (lost productivity) costs and their determinants in Canadian children and adults self-reporting FA. METHODS: FA-individuals self-reporting a convincing history or physician diagnosis were recruited through FA registries, an anaphylaxis registry, and advocacy associations, and electronically surveyed regarding FA-related healthcare use, out-of-pocket expenditures, and time lost from paid and unpaid labor. Direct and indirect costs (2020 Canadian dollars [CAD]) were stratified on severe reaction vs mild, moderate or no reaction, and children vs adults; multivariate regressions assessed the association between costs and sociodemographic and disease characteristics. RESULTS: Between May 2018 and July 2019, 2692 eligible individuals responded (2189 convincing history and 503 physician diagnosis only); 1020 experienced a severe reaction; 1752 were children. Per FA-individual, annual healthcare, out-of-pocket, and indirect costs were $1267, $2136, and $7950. Those with a severe reaction had higher healthcare and out-of-pocket costs than those with mild, moderate or no reaction. FA-children vs FA-adults had higher healthcare and out-of-pocket costs, and lower indirect costs. Multivariate results showed that lower age, a severe reaction ever, multiple FAs, and fair or poor general health were associated with higher healthcare and out-of-pocket costs. Higher age, lower household education and income, and fair or poor general health were associated with higher indirect costs. CONCLUSION: The economic burden of FA in Canada is substantial, particularly for those with a severe reaction ever, multiple FAs, and fair or poor general health. It is crucial that those most adversely affected are allocated appropriate resources to support disease management.

Sesame-induced anaphylaxis in pediatric patients from the cross-Canada anaphylaxis registry.

BACKGROUND: Sesame can cause severe allergic reactions and is a priority allergen in Canada. OBJECTIVE: To assess clinical characteristics and management of pediatric sesame-induced anaphylaxis and identify factors associated with epinephrine treatment. METHODS: Between 2011 and 2021, children with sesame-induced anaphylaxis presenting to 7 emergency departments (ED) in 4 Canadian provinces and 1 regional emergency medical service were enrolled in the Cross-Canada Anaphylaxis Registry. Standardized recruitment forms provided data on symptoms, severity, triggers, and management. Multivariate logistic regression evaluated associations with epinephrine treatment pre-ED and multiple epinephrine dosages. RESULTS: Of all food-induced anaphylactic reactions (n = 3279 children), sesame accounted for 4.0% (n = 130 children), of which 61.5% were boys, and the average (SD) age was 5.0 (4.9) years. Hummus containing sesame paste triggered 58.8% of reactions. In the pre-ED setting, 32.3% received epinephrine, and it was more likely to be used in boys (adjusted odds ratio [aOR], 1.27; 95% confidence interval [CI], 1.08-1.50) and those with a known food allergy (aOR, 1.36; 95% CI, 1.11-1.68]). In the ED, 47.7% of cases received epinephrine, with older children more likely to receive multiple epinephrine doses (aOR, 1.00; 95% CI, 1.00-1.02). CONCLUSION: In Canada, hummus is the major trigger of sesame-induced anaphylaxis. Knowledge translation focused on prompt epinephrine use and product-labeling policies are required to limit sesame reactions in communities.

Tree nut-induced anaphylaxis in Canadian emergency departments: Rate, clinical characteristics, and management.

BACKGROUND: Data are sparse regarding tree nut-induced anaphylaxis (TNA). OBJECTIVE: To characterize rate, clinical characteristics, and management of TNA in children (0-17 years old) across Canada and evaluate factors associated with severe reactions and epinephrine use. METHODS: Between April 2011 and May 2020, data were collected on children presenting to 5 emergency departments in Canada. Multivariate logistic analysis was used to evaluate factors associated with severe reactions (stridor, cyanosis, circulatory collapse, or hypoxia) and epinephrine use. RESULTS: Among 3096 cases of anaphylaxis, 540 (17%) were induced by tree nut. The median age was 5.2 (interquartile range, 2.5-9.5) years and 65.4% were of male sex. Among all reactions, 7.0% were severe. The major tree nuts accounting for anaphylaxis were cashew (32.8%), hazelnut (20.0%), and walnut (11.5%). Cashew-induced anaphylaxis was more common in British Columbia (14.0% difference [95% confidence interval (CI), 1.6-27.6]) vs Ontario and Quebec, whereas pistachio-induced anaphylaxis was more common in Ontario and Quebec (6.3% difference [95% CI, 0.5-12.2]). Prehospital and emergency department intramuscular epinephrine administration was documented in only 35.2% and 52.4% of cases, respectively. Severe reactions were more likely among of male sex (adjusted odds ratio [aOR], 1.05 [95% CI, 1.01-1.10]), older children (aOR, 1.00 [95% CI, 1.00-1.01]), and in reactions triggered by macadamia (aOR, 1.27 [95% CI, 1.03-1.57]). CONCLUSION: Different TNA patterns in Canada may be because of differences in lifestyle (higher prevalence of Asian ethnicity in British Columbia vs Arabic ethnicity in Ontario and Quebec). Intramuscular epinephrine underutilization urges for epinephrine autoinjector stocking in schools and restaurants, patient education, and consistent policies across Canada.

Seafood-induced anaphylaxis in children presenting to Canadian emergency departments: Rates, clinical presentation, and management.

BACKGROUND: There is a lack of data on seafood-induced anaphylaxis in children in Canada. OBJECTIVE: To evaluate the rate, clinical features, and management of seafood-induced anaphylaxis in children presenting to emergency departments across Canada. METHODS: Children with anaphylaxis were recruited at 6 emergency departments between 2011 and 2020 as part of the Cross-Canada Anaphylaxis REgistry. A standardized form documenting symptoms, triggers, comorbidities, and management was used to collect data. RESULTS: There were 75 fish-induced and 71 shellfish-induced cases of suspected anaphylaxis, most of which were caused by salmon and shrimp, respectively. Mucocutaneous symptoms were most common, whereas respiratory symptoms were associated with patients with fish-induced reactions who have comorbid asthma (adjusted odds ratio [aOR], 1.18; 95% confidence interval [CI], 1.02-1.36). Prehospital epinephrine was underused (<35%), whereas in-hospital epinephrine was given to less than 60% of the patients. Among those with a known fish or shellfish allergy, prehospital epinephrine use was associated with known asthma (aOR 1.39 [95% CI, 1.05-1.84] and aOR 1.25 [95% CI, 1.02-1.54], respectively). Among children who were assessed by either skin test or specific immunoglobulin E, 36 patients (76.6%) with suspected fish-induced anaphylaxis and 19 patients (51.4%) with suspected shellfish-induced anaphylaxis tested positive. CONCLUSION: Prehospital epinephrine is underused in the management of seafood-induced anaphylaxis. Among children with known seafood allergy, prehospital epinephrine use is more likely if there is a known asthma comorbidity.