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Chronic inducible urticaria (CIndU) is a subset of chronic urticaria that has an identifiable trigger. We present a case of postural urticaria induced by change in position in a 14-year-old girl. The patient’s CIndU was not adequately managed with both antihistamine and omalizumab treatment, indicating a recalcitrant form of CIndU.

Data are sparse regarding tree nut-induced anaphylaxis (TNA).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.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.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]).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.

Sesame can cause severe allergic reactions and is a priority allergen in Canada.To assess clinical characteristics and management of pediatric sesame-induced anaphylaxis and identify factors associated with epinephrine treatment.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.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).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.

Urticaria diagnosis may be challenging in children since it can be triggered or related to numerous conditions. In this paper, we reviewed the main aspects regarding the diagnosis of urticaria in the pediatric population. Acute urticaria is often due to viral infections. However, other culprits, including foods, insect stings, drugs, contrast media, vaccination, latex, and medical diseases, may account for acute patterns. Laboratory tests and confirmatory allergy tests should be individualized and guided by history. Chronic urticaria (CU) is defined when hives and/or angioedema last for more than 6 weeks. The most common type of chronic urticaria in children is chronic spontaneous urticaria (CSU). Chronic inducible urticaria (CindU) is less common but is important to diagnose in order to manage appropriately and reduce the risk of severe reactions. Inducible forms in children are often diagnosed with specific provocation tests similar to the tests used in adults. Given that chronic urticaria could rarely be a presentation of vasculitis, systemic-onset juvenile idiopathic arthritis, or auto-inflammatory syndromes, it is important to rule out these conditions. It is crucial to differentiate cases of chronic urticaria from mastocytosis and Bradykinin-mediated angioedema, given that treatment may differ. The management of chronic urticaria in children has improved over the last decade because of the development of both clear management guidelines and new effective drugs. It is crucial to increase awareness for appropriate diagnosis and new available treatment to improve the management of chronic urticaria in children.

Background Community use of epinephrine for the treatment of anaphylaxis is low. Knowledge of rates of epinephrine use in the pre–hospital setting along with identification of barriers to its use will contribute to the development of policies and guidelines. Objectives A search was conducted on PubMed and Embase in April 2020. Our systematic review focused on 4 domains: (1) epinephrine use in the pre–hospital setting; (2) barriers to epinephrine use in the pre–hospital setting; (3) cost evaluation and cost-effectiveness of epinephrine use; and (4) programs and strategies to improve epinephrine use during anaphylaxis. Methods Two meta-analyses with logit transformation were conducted to: (1) calculate the pooled estimate of the rate of epinephrine use in the pre–hospital setting among cases of anaphylaxis and (2) calculate the pooled estimate of the rate of biphasic reactions among all cases of anaphylaxis. Results Epinephrine use in the pre–hospital setting was significantly higher for children compared with adults (20.98% [95% confidence interval (CI): 16.38%, 26.46%] vs 7.17% [95% CI: 2.71%, 17.63%], respectively, P = .0027). The pooled estimate of biphasic reactions among all anaphylaxis cases was 3.92% (95% CI: 2.88%, 5.32%). Our main findings indicate that pre–hospital use of epinephrine in anaphylaxis remains suboptimal. Major barriers to the use of epinephrine were identified as low prescription rates of epinephrine autoinjectors and lack of stock epinephrine in schools, which was determined to be cost-effective. Finally, in reviewing programs and strategies, numerous studies have engineered effective methods to promote adequate and timely use of epinephrine. Conclusion The main findings of our study demonstrated that across the globe, prompt epinephrine use in cases of anaphylaxis remains suboptimal. For practical recommendations, we would suggest considering stock epinephrine in schools and food courts to increase the use of epinephrine in the community. We recommend use of pamphlets in public areas (ie, malls, food courts, etc.) to assist in recognizing anaphylaxis and after that with prompt epinephrine administration, to avoid the rare risk of fatality in anaphylaxis cases.

Chronic urticaria (CU) affects about 1% of the world population of all ages, mostly young and middle-aged women. It usually lasts for several years (> 1 year in 25-75% of patients) and often takes > 1 year before effective management is implemented. It presents as chronic spontaneous urticaria (CSU), chronic inducible urticaria (CIndU) or both in the same person. More than 25% of cases are resistant to H1 -antihistamines, even at higher doses, and third- and fourth-line therapies (omalizumab and ciclosporin) control the disease only in two-thirds of H1 -antihistamine-resistant patients. Here we review the impact of CU on different aspects of patients' quality of life and the burden of this chronic disease for the patient and society. CU may have a strong impact on health-related quality of life (HRQoL), particularly when CSU is associated with angio-oedema and/or CIndU (Dermatology Life Quality Index > 10 in 30% of patients). Comorbidities, such as anxiety and depression, which are present in more than 30% of patients with CSU, compound HRQoL impairment. Severe pruritus and the unpredictable occurrence of weals and angio-oedema are responsible for sleep disorders; sexual dysfunction; limitations on daily life, work and sports activities; interfering with life within the family and in society; and patients' performance at school and work (6% absenteeism and 25% presenteeism). Apart from treatment costs, with annual values between 900 and 2400 purchasing power parity dollars (PPP$) in Europe and the USA, CU is associated with a high consumption of medical resources and other indirect costs, which may reach a total annual cost of PPP$ 15 550.

SARS-CoV-2 has caused a worldwide pandemic that began with an outbreak of pneumonia cases in the Hubei province of China. Knowledge of those most at risk is integral for treatment, guideline implementation, and resource allocation. We conducted a systematic review and meta-analysis to evaluate comorbidities associated with severe and fatal cases of COVID-19. A search was conducted on PubMed and EmBase on 20 April 2020. Pooled estimates were collected using a random-effects model. Thirty-three studies were included in the systematic review and twenty-two in the meta-analysis. Of the total cases 40.80% (95%CI: 35.49%, 46.11%) had comorbidities, while fatal cases had 74.37% (95%CI: 55.78%, 86.97%). Hypertension was more prevalent in severe [47.65% (95%CI: 35.04%, 60.26%)] and fatal [47.90% (95%CI: 40.33%, 55.48%)] cases compared to total cases [14.34% (95%CI: 6.60%, 28.42%)]. Diabetes was more prevalent among fatal cases [24.89% (95%CI: 18.80%, 32.16%)] compared to total cases [9.65% (95%CI: 6.83%, 13.48%)]. Respiratory diseases had a higher prevalence in fatal cases [10.89% (95%CI: 7.57%, 15.43%)] in comparison to total cases [3.65% (95%CI: 2.16%, 6.1%)]. Studies assessing the mechanisms accounting for the associations between severe cases and hypertension, diabetes, and respiratory diseases are crucial in understanding this new disease, managing patients at risk, and developing policies and guidelines that will reduce future risk of severe COVID-19 disease.

Drug allergies are reported in approximately 10% of children and carry significant health and economic impacts. However, only a minority of these reported drug allergies are established on diagnostic workup. Classically, drug allergies were diagnosed by skin prick and/or intradermal tests. However, recent data reveal that a direct ingestion challenge is often an appropriate diagnostic strategy in cases of reported nonsevere reactions to penicillin derivatives in children. This article will review the prevalence, diagnosis, and management of the main culprits of pediatric drug allergies: antibiotics and nonsteroidal anti-inflammatory drugs (NSAIDs). We will also review severe cutaneous adverse reactions to drugs in children.

Bullous pemphigoid (BP) is an autoimmune blistering skin disease. Current treatment strategies are limited by their efficacy and/or side effect profile and the need for safer and effective alternatives is undeniable. We aimed to conduct a systematic review focusing on the efficacy and safety of omalizumab in BP patients. Embase, PubMed, Cochrane, and clinicaltrials.gov were searched for English and French articles published from inception to July 1, 2021, using search terms “omalizumab” OR “Xolair” OR “IGE025” OR “olizumab” AND “bullous pemphigoid.” Screening and data extraction was performed by two raters independently. The primary outcome was complete response (CR), and secondary outcomes were partial response (PR), flare-ups, adverse events/vital status. In total, 22 articles were included, with a total of 56 patients. All patients had a refractory BP with mean disease duration of 13.5 ± 20.2 months (Standard Deviation (SD)) and failed 3.1 ± 1.6 therapies and many remained corticosteroids dependent. Overall, 87.5% of patients responded to treatment (55.4% CR and 32.1% PR), 7.1% discontinued the protocol and only 5.4% were non responders. A third of patients were able to discontinue all other therapies and most others were able to discontinue or taper systemic corticosteroids to

Warts, Hypogammaglobulinemia, Infections and Myelokathexis (WHIM) is a primary immunodeficiency syndrome. Patients with WHIM syndrome are more susceptible to human papillomavirus (HPV) infections and commonly present to a dermatologist with recalcitrant to treatment warts. Other cardinal features of WHIM syndrome include recurrent sinopulmonary bacterial infections, neutropenia/lymphopenia, low levels of immunoglobulins (IgG, IgA, IgM) and myelokathexis. Research demonstrated that truncating gain-of-function mutations of the C-X-C chemokine receptor type 4 gene (CXCR4) are responsible for this disease. Plerixafor, a specific small molecule antagonist of CXCR4, is currently used for peripheral blood hematopoietic stem cell (HSC) mobilization in stem cell transplant recipients. It has recently shown promise for the treatment of WHIM syndrome in phase I/II clinical trials. In this paper we review the emerging patient clinical data for this medication and highlight the role of CXCR4 in other important skin diseases including keratinocyte carcinomas, psoriasis and cutaneous T-cell lymphoma.

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 (GALEN) 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 urticaria, i.e. chronic spontaneous urticaria and chronic 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. This article is protected by copyright. All rights reserved.

Limited data exist on the economic burden of food allergy (FA).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.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.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.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.

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

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.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.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.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.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.

Currently, no synthesis of in-school policies, practices and teachers and school staff’s food allergy-related knowledge exists. We aimed to conduct a scoping review on in-school food allergy management, and perceived gaps or barriers in these systems. We conducted a PRISMA-ScR-guided search for eligible English or French language articles from North America, Europe, or Australia published in OVID-MedLine, Scopus, and PsycINFO databases. Two reviewers screened 2010 articles’ titles/abstracts, with 77 full-text screened. Reviewers differed by language. Results were reported descriptively and thematically. We included 12 studies. Among teachers and school staff, food allergy experiences, training, and knowledge varied widely. Food allergy experience was reported in 10/12 studies (83.4%); 20.0–88.0% had received previous training (4/10 studies; 40.0%) and 43.0–72.2% never had training (2/10 studies; 20.0%). In-school policies including epinephrine auto-injector (EAI) and emergency anaphylaxis plans (EAP) were described in 5/12 studies (41.7%). Educational interventions (8/12 studies; 66.7%) increased participants’ knowledge, attitudes, beliefs, and confidence to manage food allergy and anaphylaxis vs. baseline. Teachers and school staff have more food allergy-related experiences than training and knowledge to manage emergencies. Mandatory, standardized training including EAI use and evaluation, and the provision of available EAI and EAPs may increase school staff emergency preparedness.

Increased prevalence of Autoimmune Diseases in Children with Chronic Spontaneous UrticariaMichelle Le, MD1, Lydia Zhang MD2, Sofianne Gabrielli MSc2, Connor Prosty BSc, MD(c)1, Laura May Miles LLM, MD(c)2, Elena Netchiporouk, MD, MSc1, Sharon Baum, MD3, Shoshana Greenberger, MD3, Luis F. Ensina, MD, MSc, PhD4, Fatemeh Jafarian, MD1, Xun Zhang, PhD5, Moshe Ben-Shoshan, MD, MSc21Division of Dermatology, McGill University, Montreal, QC, Canada2Division of Pediatric Allergy and Clinical Immunology, Department of Pediatrics, McGill University Health Centre, Montreal, QC, Canada3Department of Dermatology, Chaim Sheba Medical Center, Tel-Aviv University, Sackler School of Medicine, Tel Hashomer, Israel4Department of Pediatrics, Federal University of Sao Paolo, Brazil5Centre for Outcome Research and Evaluation, Research Institute of McGill University Health Centre, Montreal, QC, CanadaCorrespondence: Michelle Le, M.D., 1001 Decarie Blvd, Montreal, Quebec, H4A 3J1 email: michelle.le@mail.mcgill.caArticle type: LetterManuscript word count: 981References : 10Tables : 1Figures: NoneFunding sources : NoneConflicts of interest: None declaredIRB Approval Status : Reviewed and approved by McGill University Health Centre; approval 12-255GEN

Background This study focuses on the side effects of cow's milk oral immunotherapy (CM-OIT) using consensus definitions of food-induced anaphylaxis. Objective To evaluate the risk of allergic reactions (ARs) and to identify risk factors associated with higher risk of anaphylactic ARs (AARs) during CM-OIT in children. Methods Clinical charts of children receiving CM-OIT were carefully reviewed. ARs were defined as single-organ ARs, and AARs were defined as involvement of 2 organ systems and/or hypotension in response to CM protein. Descriptive statistics were used to represent demographics, occurrence, reaction characteristics, and comorbidities. Poisson analysis was performed to evaluate risk factors associated with AARs. Results Among 41 children undergoing CM-OIT, 11 discontinued the treatment (N = 26.8%). The mean age at challenge was 12.1 years (standard deviation [SD], 3.6) and half were male (56.1%). The mean number of AARs per patient was 6.0 (SD, 3.5) versus a mean of 17.4 (SD, 11.9) non-AARs per patient. Among withdrawals from OIT, the mean number of AARs per patient was 8.3 versus 5.1 in nonwithdrawals. AARs were more frequent in children with higher specific IgE (sIgE) for α-lactalbumine and casein at baseline (1.11 [95% confidence interval (CI): 1.01, 1.22] and 1.01 [1.0, 1.03], respectively). Children with resolved eczema and higher sIgE for β-lactoglobuline at baseline (0.13 [95% CI: 0.04, 0.46] and 0.96 [95% CI: 0.94, 0.99], respectively) were less likely to develop AARs. Conclusions Although the majority of ARs during OIT are nonanaphylactic, AARs occur frequently. Children with higher sIgE for α-lactalbumine and casein at baseline seem to be at higher risk for AARs during OIT.

This cohort study examines a clinical decision model for penicillin allergies among pediatric patients; the model considers when reactions occurred; whether patients experienced angioedema, anaphylaxis, or a severe cutaneous adverse reaction; and whether treatment was required.

Type 2 immunity, illustrated by T helper 2 lymphocytes (Th2) and downstream cytokines (IL-4, IL-13, IL-31) as well as group 2 innate lymphoid cells (ILC2), is important in host defense and wound healing.1The hallmark of type 2 inflammation is eosinophilia and/or high IgE counts and is best recognized in atopic diathesis. Persistent eosinophilia, such as seen in hypereosinophilic syndromes, leads to fibrosis and hence therapeutic Type 2 inhibition in fibrotic diseases is of high interest. Furthermore, as demonstrated in cutaneous T cell lymphoma, advanced disease is characterized by Th1 to Th2 switch allowing cancer progression and immunosuppression. Development of targeted monoclonal antibodies against IL-4Rα (eg, dupilumab) led to a paradigm shift for the treatment of atopic dermatitis (AD) and stimulated research to better understand the role of Type 2 inflammation in other skin conditions. In this review, we summarize up to date knowledge on the role of Type 2 inflammation in skin diseases other than AD and highlight whether the use of Type 2 targeted therapies has been documented or is being investigated in clinical trials. This manuscript reviews the role of Type 2 inflammation in dermatitis, neurodermatitis, IgE-mediated dermatoses (eg, bullous pemphigoid, chronic spontaneous urticaria), sclerodermoid conditions and skin neoplasms.

Background Oral immunotherapy (OIT) is an emerging treatment for cow’s milk protein (CMP) allergy in children. The mechanisms driving tolerance following OIT are not well understood. Regulatory T cells (TREG) cells are key inhibitors of allergic responses and promoters of allergen-specific tolerance. In an exploratory study, we sought to detect induction of allergen-specific TREG in a cohort of subjects undergoing OIT. Methods Pediatric patients with a history of allergic reaction to cow’s milk and a positive Skin Pick Test (SPT) and/or CMP-specific IgE >0.35 kU, as well as a positive oral challenge to CMP underwent OIT with escalating doses of milk and were followed for up to 6 months. At specific milestones during the dose escalation and maintenance phases, casein-specific CD4+ T cells were expanded from patient blood by culturing unfractionated PBMCs with casein in vitro. The CD4+ T cell phenotypes were quantified by flow cytometry. Results Our culture system induced activated casein-specific FOXP3+Helios+ TREG cells and FOXP3- TEFF cells, discriminated by expression of CD137 (4-1BB) and CD154 (CD40L) respectively. The frequency of casein-specific TREG cells increased significantly with escalating doses of milk during OIT while casein-specific TEFF cell frequencies remained constant. Moreover, expanded casein-specific TREG cells expressed higher levels of FOXP3 compared to polyclonal TREG cells, suggesting a more robust TREG phenotype. The induction of casein-specific TREG cells increased with successful CMP desensitization and correlated with increased frequencies of casein-specific Th1 cells among OIT subjects. The level of casein-specific TREG cells negatively correlated with the time required to reach the maintenance phase of desensitization. Conclusions Overall, effective CMP-OIT successfully promoted the expansion of casein-specific, functionally-stable FOXP3+ TREG cells while mitigating Th2 responses in children receiving OIT. Our exploratory study proposes that an in vitro TREG response to casein may correlate with the time to reach maintenance in CMP-OIT.

Background Data are sparse regarding the clinical characteristics and management of fruit-induced anaphylaxis. Objective To assess clinical characteristics and management of patients with fruit-induced anaphylaxis and determine factors associated with severe reactions and epinephrine use. Methods Over 9 years, children and adults presenting with anaphylaxis to seven emergency departments in four Canadian provinces and patients requiring emergency medical services in Outaouais, Quebec were recruited as part of the Cross-Canada Anaphylaxis Registry. A standardized form documenting symptoms, triggers, and management was collected. Multivariate logistic regression was used to identify factors associated with severe reactions and epinephrine treatment in the pre-hospital setting. Results We recruited 250 patients with fruit-induced anaphylaxis, median age 10.2 years (interquartile range, 3.6-23.4 years); 48.8% were male. The most common fruit triggers were kiwi (15.6%), banana (10.8%), and mango (9.2%). Twenty-three patients reported having eczema (9.3%). Epinephrine use was low in both the pre-hospital setting and the emergency department (28.4% and 40.8%, respectively). Severe reactions to fruit were more likely to occur in spring and among those with eczema (adjusted odds ratio [aOR] = 1.12, 95% confidence interval [CI], 1.03-1.23; and 1.17, 95% CI, 1.03-1.34, respectively). Patients with moderate and severe reactions (aOR = 1.23; 95% CI, 1.06-1.43) and those with a known food allergy (aOR = 1.38; 95% CI, 1.24-1.54) were more likely to be treated with epinephrine in the pre-hospital setting. Conclusions Severe anaphylaxis to fruit is more frequent in spring. Cross-reactivity to pollens is a potential explanation that should be evaluated further.

To Howard Miller, Editor in Chief:In the letter to the editor ‘Differences in the prevalence of positive penicillin allergy test results in children and adults,’ the authors presented results of th...

Background Data on the diagnostic properties of direct oral challenges without the use of skin tests in children with suspected amoxicillin allergy are sparse. Objective Assess the use of direct oral challenges. Methods A cohort study was conducted between March 2013 and March 2020, in Montreal and Winnipeg. All children referred with reported history of benign reactions (ie, limited to the skin with no mucosal lesions and no vesicles) to amoxicillin were recruited and a 2-step graded oral challenge (GOC) was conducted. Data were collected on demographic characteristics, clinical characteristics, and comorbidities. Eligible children were followed to assess reactions to subsequent use of amoxicillin and to assess the safety of cephalexin use in children with a positive GOC. Results Among 1914 children recruited, 1811 (94.6%) tolerated the GOC, 42 (2.2%) developed mild immediate reactions, and 61 (3.2%) developed mild nonimmediate reactions. Among 265 participants who had a negative GOC and reused amoxicillin, 226 (85.3%) reported tolerance and 39 (14.7%) had mild cutaneous reactions. Chronic urticaria (adjusted odds ratio [aOR], 1.16; 95% CI, 1.09-1.23) and an index reaction occurring within 5 minutes of exposure (aOR, 1.09; 95% CI, 1.04-1.14) were associated with immediate reactions during the GOC. Symptoms lasting longer than 7 days (aOR, 1.05; 95% CI, 1.02-1.09) and parental drug hypersensitivity (aOR, 1.04; 95% CI, 1.03-1.06) were associated with nonimmediate reactions. Among those reacting to the GOC, 12.5% reacted with mild cutaneous reactions to cephalexin challenge. Conclusions Direct GOCs are an accurate and safe confirmatory to establish true hypersensitivity among children reporting benign reactions to amoxicillin.

Concerns for anaphylaxis may hamper severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunization efforts. We convened a multidisciplinary group of international experts in anaphylaxis composed of allergy, infectious disease, emergency medicine, and front-line clinicians to systematically develop recommendations regarding SARS-CoV-2 vaccine immediate allergic reactions. Medline, EMBASE, Web of Science, the World Health Organizstion (WHO) global coronavirus database, and the gray literature (inception, March 19, 2021) were systematically searched. Paired reviewers independently selected studies addressing anaphylaxis after SARS-CoV-2 vaccination, polyethylene glycol (PEG) and polysorbate allergy, and accuracy of allergy testing for SARS-CoV-2 vaccine allergy. Random effects models synthesized the data to inform recommendations based on the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) approach, agreed upon using a modified Delphi panel. The incidence of SARS-CoV-2 vaccine anaphylaxis is 7.91 cases per million (n = 41,000,000 vaccinations; 95% confidence interval [95% CI] 4.02-15.59; 26 studies, moderate certainty), the incidence of 0.15 cases per million patient-years (95% CI 0.11-0.2), and the sensitivity for PEG skin testing is poor, although specificity is high (15 studies, very low certainty). We recommend vaccination over either no vaccination or performing SARS-CoV-2 vaccine/excipient screening allergy testing for individuals without history of a severe allergic reaction to the SARS-CoV-2 vaccine/excipient, and a shared decision-making paradigm in consultation with an allergy specialist for individuals with a history of a severe allergic reaction to the SARS-CoV-2 vaccine/excipient. We recommend further research to clarify SARS-CoV-2 vaccine/vaccine excipient testing utility in individuals potentially allergic to SARS-CoV2 vaccines or their excipients.

Food-induced allergic reactions are diagnosed through corroboration of a suggestive clinical history with appropriate confirmatory tests. The major confirmatory tests include skin prick tests and serum specific immunoglobulin E (sIgE) levels. When the diagnosis is inconclusive, oral food challenges are performed (1).

Background Children are often diagnosed with an antibiotic allergy, with little investigation to confirm whether it is a true allergy. Recent studies support the use of oral challenges to confirm antibiotic allergy. Yet, little is known about families' perceptions of these challenges, or experiences of living with a misdiagnosis, often for many years. Objective To describe how families with a child previously labelled as "antibiotic allergic," but who has subsequently been delabelled, perceive the experience of misdiagnosis and subsequent delabelling. Methods We performed semi-structured interviews with parents whose children had recently completed a graded oral challenge for antibiotic allergy. Interview transcripts were analysed concurrently, but independently, by two investigators, using content analysis. Results A total of 15 parents (14 individual interviews; 1 mother-father dyad) participated. Children were, on average, 5.04 ± 4.5 years and were first diagnosed in infancy (mean age: 1.82 ± 1.48 years) subsequent to a rash (14/14; 100%), and commonly at a walk-in clinic (6/14; 42.9%). We identified four themes: (1) A red, raised rash results in a quick diagnosis despite a lack of testing, (2) sensitive care allays concerns, (3) delabelling brings relief, but also mystery and calls for proper diagnoses, and (4) quick diagnoses are reckless, but manageable through downward comparisons. Conclusion and clinical relevance These findings underscore the importance of a careful physical examination and clinical history of the patient, but also an ongoing dialogue to support families, both of which would ideally begin at the time of initial investigation.

Background Serum sickness–like reactions (SSLRs) are defined by the presence of rash (primarily urticaria) and joint complaints (arthralgia/arthritis) that are believed to occur due to a non–IgE-mediated response to medications. However, similar reactions can occur due to viral infections, and it can be difficult to distinguish between the two. This may lead to unnecessary avoidance of the culprit antibiotic. Objective We aimed to evaluate children presenting with suspected SSLRs through a graded oral challenge (GOC). Methods All children referred to the Montreal Children's Hospital for potential antibiotic allergy (β-lactam or other antibiotics) and a clinical presentation compatible with SSLR were recruited for the study between March 2013 and February 2020. A standardized survey with questions on treatment, symptoms, and associated factors was completed, and a GOC (10% and subsequently 90% of the oral antibiotic dose) was conducted. Patients with a negative GOC were contacted annually to query on subsequent antibiotic use. Results Among 75 patients presenting with suspected SSLRs, the median age was 2.0 years and 46.7% were males. Most reactions were attributed to amoxicillin. Among the 75 patients, 2.7% reacted immediately (within 1 hour) to a GOC and 4.0% had a nonimmediate reaction. Of the 43 patients successfully contacted, 20 reported subsequent culprit antibiotic use of whom 25.0% had a subsequent mild reaction (macular/papular rash). Conclusions This is the first and largest pediatric study to assess SSLR using a GOC. Our findings suggest that using a GOC is safe and appropriate for differentiating between β-lactam-induced SSLR and viral exanthem in this population.

BACKGROUND: It is not established whether the risk of anaphylaxis induced by peanuts or tree nuts in children increases at specific times of the year. We aimed to evaluate the risk of peanut-and tree-nut–induced anaphylaxis during certain cultural holidays in Canadian children. METHODS: We collected data on confirmed pediatric cases of anaphylaxis presenting to emergency departments in 4 Canadian provinces as part of the Cross-Canada Anaphylaxis Registry. We assessed the mean number of cases per day and incidence rate ratio (IRR) of anaphylaxis induced by unknown nuts, peanuts and tree nuts presenting during each of 6 holidays (Halloween, Christmas, Easter, Diwali, Chinese New Year and Eid al-Adha) versus the rest of the year. We estimated IRRs and 95% confidence intervals (CIs) using Poisson regression. RESULTS: Data were collected for 1390 pediatric cases of anaphylaxis between 2011 and 2020. Their median age was 5.4 years, and 864 (62.2%) of the children were boys. During Halloween and Easter, there were higher rates of anaphylaxis to unknown nuts (IRR 1.66, 95% CI 1.13–2.43 and IRR 1.71, 95% CI 1.21–2.42, respectively) and peanuts (IRR 1.86, 95% CI 1.12–3.11 and IRR 1.57, 95% CI 0.94–2.63, respectively) compared to the rest of the year. No increased risk of peanut- or tree-nut–induced anaphylaxis was observed during Christmas, Diwali, Chinese New Year or Eid al-Adha. Anaphylaxis induced by unknown nuts, peanuts and tree nuts was more likely in children aged 6 years or older than in younger children. INTERPRETATION: We found an increased risk of anaphylaxis induced by unknown nuts and peanuts during Halloween and Easter among Canadian children. Educational tools are needed to increase awareness and vigilance in order to decrease the risk of anaphylaxis induced by peanuts and tree nuts in children during these holidays.

Within the broad category of adverse drug reactions in children, there has been a recent focus specifically on the evaluation of children with antibiotic allergy, in particular, beta-lactam allergy. The potential consequences of being labeled beta-lactam allergy are increasingly recognized. Appropriate evaluation of children with suspected reactions to antibiotics is essential as it is increasingly being recognized that the label of “penicillin allergy” is associated with adverse health and economic outcomes. This review will focus on the 3 main classes of antibiotics reported to cause allergic reactions in children: beta lactams (penicillin derivatives and cephalosporins), macrolides, and sulfonamides. This article is a narrative review of the prevalence, diagnosis, and management of different types of antibiotic allergies in children. Our review reveals that antibiotic allergy is often overreported and not appropriately diagnosed in the pediatric age groups. There is a recent shift in the diagnostic paradigm from the use of skin tests and if negative challenges to the use of challenge only in the pediatric age group. Larger studies to establish the usefulness and safety of this new approach as well as updated guidelines are needed.

Background Cold urticaria is a subtype of chronic inducible urticaria (CIndU) associated with significant morbidity and a risk of anaphylaxis. Few studies have assessed the prevalence, management, and prevalence of associated anaphylaxis of cold urticaria. Objectives To evaluate the prevalence of cold urticaria among CIndU and chronic urticaria (CU) cases, to assess the management of cold urticaria and to determine the prevalence of associated anaphylaxis. Methods PubMed and EMBASE were searched for studies pertaining to cold urticaria and/or CIndU published in the last 10 years. Meta-analyses were conducted to evaluate: the prevalence of cold urticaria among CIndU and chronic urticaria (CU) cases, the management of cold urticaria with H1-antihistamines and omalizumab and the prevalence of associated anaphylaxis. Results Twenty-two studies were included in the systematic review and 14 in the meta-analysis. The pooled prevalence of cold urticaria among CU and CIndU cases were 7.62% (95%CI: 3.45%, 15.99%; I2=98%) and 26.10% (95%CI: 14.17%, 43.05%; I2= 97%), respectively. Cold urticaria was managed by H1-antihistamines in 95.67% (95%CI: 92.47%, 97.54%; I2=38%) of patients and omalizumab in 5.95% (95%CI: 2.55%, 13.27%; I2=83%) of patients. The pooled prevalence of anaphylaxis among cold urticaria cases was 21.49% (95%CI: 15.79%, 28.54%; I2=69%). Conclusion Cold urticaria constitutes an appreciable proportion of CIndU and CU cases and is predominantly managed with H1-antihistamines, with a minority of patients receiving omalizumab. Anaphylaxis is not rare, and epinephrine auto-injector (EAI) prescription may be considered.

BACKGROUND: Peanut allergy, for which there are no approved treatment options, affects patients who are at risk for unpredictable and occasionally life-threatening allergic reactions.METHODS: In a phase 3 trial, we screened participants 4 to 55 years of age with peanut allergy for allergic dose-limiting symptoms at a challenge dose of 100 mg or less of peanut protein (approximately one third of a peanut kernel) in a double-blind, placebo-controlled food challenge. Participants with an allergic response were randomly assigned, in a 3:1 ratio, to receive AR101 (a peanut-derived investigational biologic oral immunotherapy drug) or placebo in an escalating-dose program. Participants who completed the regimen (i.e., received 300 mg per day of the maintenance regimen for approximately 24 weeks) underwent a double-blind, placebo-controlled food challenge at trial exit. The primary efficacy end point was the proportion of participants 4 to 17 years of age who could ingest a challenge dose of 600 mg or more, without dose-limiting symptoms.RESULTS: Of the 551 participants who received AR101 or placebo, 496 were 4 to 17 years of age; of these, 250 of 372 participants (67.2%) who received active treatment, as compared with 5 of 124 participants (4.0%) who received placebo, were able to ingest a dose of 600 mg or more of peanut protein, without dose-limiting symptoms, at the exit food challenge (difference, 63.2 percentage points; 95% confidence interval, 53.0 to 73.3; PCONCLUSIONS: In this phase 3 trial of oral immunotherapy in children and adolescents who were highly allergic to peanut, treatment with AR101 resulted in higher doses of peanut protein that could be ingested without dose-limiting symptoms and in lower symptom severity during peanut exposure at the exit food challenge than placebo. (Funded by Aimmune Therapeutics; PALISADE ClinicalTrials.gov number, NCT02635776 .).

There are substantial knowledge gaps related to diagnosis and management of pediatric cases of chronic urticaria, and in particular chronic spontaneous urticaria (CSU). In this article we aimed to review the diagnosis and management of chronic urticaria in children and CSU in particular. We conducted a systematic review of articles published in English and French on pediatric CSU management in the last 10 years. We included experimental studies (eg, randomized controlled trials), other experimental designs (eg, nonrandomized methods of assignment, controlled before-after studies, and interrupted time series), and observational studies (eg, prospective or retrospective cohort studies, cross-sectional studies, case-control studies, and case reports). Our findings highlight the efficacy of second-generation antihistamines for the treatment of CSU in children and supports the use of omalizumab for more severe cases. However, our study also reveals severe knowledge gaps related to the best management strategy in children with more severe/refractory cases of CSU. Future studies are required to establish the beneficial effect of high doses of second-generation antihistamines as well as the effectiveness and safety of omalizumab and other biologics in young children.

_To the Editor:_ Previously, we identified the HLA region as a risk factor forpeanut allergy (PA); this observation is supported further by 2 independent genome-wide association studies (GWASs). The HLA class II genes (including HLA-DR, HLA-DQ, and HLADP) encode molecules involved in presentation of extracellular antigens, such as peanut allergens, to T lymphocytes, which in turn mediates B-cell antibody production.We used the Canadian Peanut Allergy Registry (CanPAR) and the Busselton Health Study to conduct the largest GWAS for PA to date. Here we report analysis of the HLA region and a meta-analysis with data from 6 additional studies, which confirms and narrows the region of interest to HLA-DQB1 and establishes independence from asthma loci. [...]

BACKGROUND Food desensitization via oral immunotherapy (OIT) is gaining higher acceptance in clinical practice. Due to adverse reactions, the duration of the build-up phase until a maintenance dose is achieved may be prolonged, and in a minority of cases, OIT is stopped. OBJECTIVE We aimed to assess factors associated with the probability of reaching the maintenance dose in cow’s milk (CM) OIT. METHODS Data was collected from patients undergoing CM OIT at the Montreal Children’s Hospital, BC Children’s Hospital, and Hospital for Sick Children. We compared uni- and multivariable Cox regressions to evaluate sociodemographic factors, co-morbidities, clinical characteristics and biomarkers at study entry associated with the likelihood of reaching a maintenance dose of 200 mL of CM. RESULTS Among 69 children who reached 4 mL of milk, the median age was 12 years (Interquartile Range [IQR] 9-15) and 59% were male. The median duration of build-up phase from 4 mL to 200 mL was 24.0 weeks (IQR 17.7-33.4). After adjusting for age and sex, higher baseline levels of specific IgE (sIgE) antibodies for α-lactalbumin (ALA, hazard ratio [HR] 0.80, 95% confidence interval [CI] 0.67-0.95), β-lactoglobulin (BLG, HR 0.86, 95% CI 0.76-0.98), casein (HR 0.82, 95% CI 0.72-0.94), and total CM (HR 0.79, 95% CI 0.65-0.97), were associated with a decreased probability of reaching maintenance. Additionally, for every increase of 10 mL CM tolerated at entry challenge, the probability of reaching maintenance increased by 10%. CONCLUSION The data suggest that higher levels of CM-sIgE decreased the likelihood of reaching maintenance, while an increased cumulative CM dose at entry challenge increased the likelihood. Assessing these factors prior to therapy may assist in predicting the success of CM OIT.

Objective Limited evidence suggests a potentially increased risk of allergic conditions in offspring born to women with systemic lupus erythematosus (SLE). In a large population-based study, we aimed to determine if children born to mothers with SLE have an increased risk of allergic conditions compared to children born to mothers without SLE. Methods Using the Offspring of SLE Mothers Registry, we identified children born live to mothers with SLE and their matched controls, and ascertained the number of allergic conditions (asthma, allergic rhinitis, eczema, urticaria, angioedema, and anaphylaxis) based on ≥1 hospitalization or ≥1 or 2 physician(s) visit(s) with a relevant diagnostic code. We adjusted for maternal age, education, race/ethnicity, obstetrics complications, calendar year of birth, sex of the child, and maternal medication. Results There were 509 women with SLE who had 719 children, while 5,824 matched controls had 8,493 children. The mean ± SD followup period was 9.1 ± 5.8 years. Compared to controls, more children born to mothers with SLE had evidence of allergic conditions (43.9% [95% confidence interval (95% CI) 40.4-47.6] versus 38.1% [95% CI 37.0-39.1]). In multivariate analysis (n = 9,212), children born to mothers with SLE had an increased risk of allergic conditions versus control children (odds ratio 1.35 [95% CI 1.13-1.61]). Conclusion Compared to children from the general population, children born to women with SLE may have an increased risk of allergic conditions. Genetics, shared environmental exposures, as well as in utero exposure to maternal autoantibodies and cytokines may mediate this increased risk.

Background Peanut allergy (PA) is a complex disease with both environmental and genetic risk factors. Previously, PA loci were identified in filaggrin (FLG) and HLA in candidate gene studies, and loci in HLA were identified in a genome-wide association study and meta-analysis. Objective We sought to investigate genetic susceptibility to PA. Methods Eight hundred fifty cases and 926 hyper-control subjects and more than 7.8 million genotyped and imputed single nucleotide polymorphisms (SNPs) were analyzed in a genome-wide association study to identify susceptibility variants for PA in the Canadian population. A meta-analysis of 2 phenotypes (PA and food allergy) was conducted by using 7 studies from the Canadian, American (n = 2), Australian, German, and Dutch (n = 2) populations. Results An SNP near integrin α6 (ITGA6) reached genome-wide significance with PA ( P = 1.80 × 10 −8 ), whereas SNPs associated with Src kinase–associated phosphoprotein 1 (SKAP1) , matrix metallopeptidase 12 (MMP12)/MMP13 , catenin α3 (CTNNA3) , rho GTPase–activating protein 24 (ARHGAP24) , angiopoietin 4 (ANGPT4) , chromosome 11 open reading frame (C11orf30/EMSY) , and exocyst complex component 4 (EXOC4) reached a threshold suggestive of association ( P ≤ 1.49 × 10 −6 ). In the meta-analysis of PA, loci in or near ITGA6 , ANGPT4 , MMP12/MMP13 , C11orf30 , and EXOC4 were significant ( P ≤ 1.49 × 10 −6 ). When a phenotype of any food allergy was used for meta-analysis, the C11orf30 locus reached genome-wide significance ( P = 7.50 × 10 −11 ), whereas SNPs associated with ITGA6 , ANGPT4 , MMP12/MMP13 , and EXOC4 and additional C11orf30 SNPs were suggestive ( P ≤ 1.49 × 10 −6 ). Functional annotation indicated that SKAP1 regulates expression of CBX1 , which colocalizes with the EMSY protein coded by C11orf30. Conclusion This study identifies multiple novel loci as risk factors for PA and food allergy and establishes C11orf30 as a risk locus for both PA and food allergy. Multiple genes ( C11orf30 / EMSY , SKAP1 , and CTNNA3 ) identified by this study are involved in epigenetic regulation of gene expression.

Common variable immunodeficiency (CVID) is characterized by hypogammaglobulinemia and clinical manifestations such as infections, autoimmunity, and malignancy. We sought to determine if responsiveness to interleukin-21 (IL-21), a key cytokine for B cell differentiation, correlates with distinct clinical phenotypes in CVID. CVID subjects were recruited through the Canadian Primary Immunodeficiency Evaluative Survey registry. Peripheral blood mononuclear cells were cultured with anti-CD40 ± interferon-gamma, interleukin-4 (IL-4), IL-21, and/or IL-4+IL-21. B cell subpopulations and IgG production were determined at baseline and day 7 by flow cytometry and ELISA. Clinical complications were compared using contingency tables. CVID subjects exhibited decreased CD27+ B cells and IgG production after 7 days of stimulation with anti-CD40+IL-21 (p 2% class-switched memory B cells at baseline. The IL-4 and IL-21 in vitro assays distinguish two groups of CVID subjects and can be used with baseline B cell subpopulation phenotyping to better identify patients experiencing more vs. fewer clinical non-infectious complications and potentially to modulate therapy.