A case of postural urticaria in a 14-year-old girlSofianne Gabrielli, MSc1, Michelle Le, MD2, Elena Netchiporouk, MD, MSc2, Moshe Ben-Shoshan, MD, MSc11Division of Allergy, Immunology and Dermatology, Montreal Children’s Hospital, Montreal,QC, Canada.2Division of Dermatology, McGill University, Montreal, QC, Canada.Keywords: urticaria, postural urticaria, antihistamines, omalizumabTo the Editor,Chronic urticaria (CU) is defined by the presence of wheals and/or angioedema for more than six weeks1. CU is classified as spontaneous (CSU) or inducible (CIndU) urticaria, based on the ability to identify a trigger1. CIndU, which can be classified into physical and non-physical forms, is less common than CSU and can be diagnosed by provocation test. We describe the case of a 14-year-old female patient with postural urticaria induced by changing from a seating to standing position. To our knowledge, there is only one other case of postural urticaria described in a teenage boy2.A 14-year-old female patient presented with a two-year history of intermittent hives on her bilateral legs which developed 20 minutes after standing. The patient also described symptoms of tingling in her legs prior to the development of the hives. The symptoms usually resolved after a few hours. In addition, the patient reported spontaneous hives almost daily not related to an identifiable trigger. The patient was otherwise healthy and was not taking any medication. The patient’s father reported a history of urticaria in childhood which resolved, although he still rarely experiences episodes of hives.Upon examination, the patient developed prominent vasculature (livedo reticularis) and urticaria on her bilateral legs 20 minutes after changing from a seated to a standing position (Figure 1A and 1B). When seated, the patient’s blood pressure was 113/77 and her heart rate was 102. Upon standing, the patient’s blood pressure was 101/82 and her heart rate was 118. All laboratory tests, which included a complete blood count, thyroid stimulating hormone, anti-thyroid peroxidase Immunoglobulin (Ig) G, tryptase, and total IgE, were within the normal limits. The patient’s weekly Urticaria Activity Score (UAS7) in the week prior to exam was 9.Given poor response to standard doses of second-generation anti-histamines, the patient was treated with bilastine 40 mg twice daily. After one year, due to poor response to treatment, the patient was placed on 300 mg of omalizumab administered once per month. Over the period of one year, the patient did experience improvement in her spontaneous urticaria symptoms, with her UAS7 decreasing from 38 to 9 over a period of two years. However, there was no improvement in the symptoms related to change in posture.The mechanism of action of postural urticaria in this patient is unknown. It was previously hypothesized that change in venous pressure or blood flow volume from sitting to standing may induce the release of mediators such as acetylcholine that may induce hive development2.The management of postural urticaria in our patient was not clear as she did not improve with antihistamines, nor with the addition of omalizumab treatment. It possible that the patient may gain better control of her hives with other management strategies, such as a higher dose of omalizumab3 or a different biologic, such as ligelizumab4. Clinicians should be made aware of this presentation of postural urticaria given that it may reflect a more recalcitrant form of CIndU. We suggest that a provocation test consisting of standing for 10 to 20 minutes should be used to confirm the diagnosis of postural urticaria.

Demographic Characteristics associated with Food Allergy in a Nationwide Canadian StudyTo the Editor,We conducted a nationwide Canadian telephone survey on food allergy (FA) prevalence between 02/2016 and 01/2017 (SPAACE [S urveying P revalence of FoodA llergy in A ll C anadianE nvironments] to SPAACE [S2S]1], targeting vulnerable populations (New, Indigenous, and lower-income Canadians) using 2006 Canadian Census data (Appendix). We compared prevalence between vulnerable and non-vulnerable populations2 and reported (in univariable analysis) that prevalence was lower in immigrants and less-educated adults. We now examine the independent effect of these and other characteristics (age, sex, race/ethnicity, and household size) on FA.The adult household respondent completed the Food Allergy Prevalence Questionnaire (FAPQ)1,3,4 for each household member (Appendix). Food allergy was defined as perceived (self-report of any FA) or probable (self-report of a convincing history (Appendix) and/or physician diagnosis of a peanut, tree nut, fish, shellfish, sesame, milk, egg, wheat, and/or soy allergy).1,4 The Research Ethics Boards of the Universities of Calgary and Waterloo approved the study. The association between perceived and probable FA and demographic characteristics was assessed through weighted univariable and multivariable random effects logistic regressions (Appendix).Of 11,592 eligible households, 5874 completed the FAPQ (50.7% household response rate), providing data on 14,818 individuals (Table 1).In multivariable analyses, adults ≥45 years (OR 0.69, 95% confidence interval (CI) 0.56, 0.86), New Canadians (OR 0.51, 95%CI 0.38, 0.69), those immigrating to Canada ≥10 years prior (OR 0.75, 95%CI 0.62, 0.92), and those residing in larger households (OR 0.82, 95%CI 0.75, 0.90) were less likely to report any perceived FA (Table 2). Females (OR 1.49, 95%CI 1.27, 1.74) and adults with post-secondary education (OR 1.20, 95%CI 1.02, 1.43) were more likely to reportperceived FA.New Canadians (OR 0.46, 95%CI 0.30, 0.68), those immigrating ≥10 years prior (OR 0.64, 95%CI 0.49, 0.82), and those residing in larger households (OR 0.85, 95%CI 0.77, 0.94) were less likely to reportprobable FA, whereas children (OR 1.95, 95%CI 1.38, 2.75), females (OR 1.49, 95%CI 1.22, 1.82), and adults with post-secondary education (OR 1.55, 95%CI 1.23, 1.96) were more likely to reportprobable FA.In addition to many of the characteristics associated with any FA, race/ethnicity was also associated with some individual FA (Supplemental Table 1A&B).When the sample was restricted to parents with at least one Canadian-born child, Asian-born parents were less likely to report anyperceived (OR 0.40, 95%CI 0.24, 0.66) and probable FA (OR 0.29, 95%CI 0.14, 0.61) (Supplemental Table 2). However, Canadian-born children of Asian-born parents were more likely to report anyperceived (OR 1.77, 95% CI 1.13, 2.76) and probable FA (OR 2.11, 95% CI 1.29, 3.43).We have shown that while children, females, and adults with post-secondary education were more likely to report at least oneperceived or probable FA and adults ≥ 45 years, immigrants, and those in larger households were less likely to report FA, Asian and Indigenous race/ethnicity were associated with specific foods. It is likely that our observed association between FA and higher education and Canadian birthplace is attributable to increased FA awareness, better healthcare access, and differing genetic and environmental influences. The association between larger household size and decreased FA supports the hygiene hypothesis.5 Our paradoxical finding of a lower odds of FA in Asian-born parents of Canadian-born children and a higher odds of FA in Canadian-born children of Asian-born parents suggests that early life environmental exposures, such as climate, dietary, and microbial, exert a differential effect depending on genetic background.Although our nationwide sampling frame precluded food challenges and only included households with landlines and nonresponse bias may have influenced our results, we have demonstrated clear associations between demographic characteristics and FA, potentially important clues to environmental determinants.

ABSTRACT Background No validated tools exist to evaluate chronic urticaria (CU) control in children. While the Urticaria Control Test (UCT) exhibits favourable clinometric properties in adult CU, it is not yet validated in children. Therefore, we sought to evaluate the validity of the UCT for the assessment of pediatric CU. Methods Children presenting with CU were consecutively recruited. Participants completed both the UCT and the Children’s Dermatology Life Quality Index (CDLQI). We assessed the internal consistency, convergent and known-groups validity, and screening accuracy of the UCT at study entry and at follow-up. Results A total of 52 children with CU were recruited. The UCT exhibited respectable internal consistency in the evaluation of CU (Cronbach’s α=0.73 [95%CI: 0.62, 0.85]). UCT and CDLQI scores strongly correlated (r=-0.74, P<0.01). The UCT distinguished between different strata of disease severities established by the CDLQI (P<0.01). Screening accuracy of the UCT was excellent in the discrimination of poorly controlled CU (area under the curve=0.82). An optimal cut-off of ≤10 was determined for defining poorly controlled CU (sensitivity=95.5%, specificity=63.3%). Data at follow-up were consistent with data at study entry. Conclusion The UCT is a valid tool for the assessment of pediatric CU and CSU, as evidenced by acceptable internal consistency, convergent and known-groups validity, and screening accuracy at multiple time points.

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.

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 São Paolo, Brazil5Centre for Outcome Research and Evaluation, Research Institute of McGill University Health Centre, Montreal, QC, CanadaCorrespondence: Michelle Le, M.D., 1001 Decarie Blvd, Montréal, Québec, H4A 3J1 email: [email protected] 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