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.

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.

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.

Mohs Micrographic Surgery Is Equivalent to Nail Unit Excision or Amputation for Melanoma In Situ of the Nail Unit: A Systematic Review and Meta-Analysis.

BACKGROUND: Local recurrence (LR) rates of melanoma in situ (MIS) of the nail apparatus treated with different surgical modalities are unknown. OBJECTIVE: To evaluate the differences in LR rates of nail apparatus MIS treated with Mohs micrographic surgery (MMS) versus nail unit excision (NUE) versus amputation. METHODS: Studies of nail/subungual MIS treated with MMS, NUE, or amputation were identified through multiple literature databases, including PubMed, MEDLINE, Embase, Web of Science, and Cochrane Library. Pooled data were assessed through meta-analyses and Fisher exact test. RESULTS: Of 280 studies identified, 20 met inclusion criteria (7 comparative studies and 13 single-arm studies). Among the 7 comparative studies, the LR was 4.38% (5/114) after NUE and 2.94% (1/34) after amputation (odds ratio: 0.937; 95% CI: 0.237-3.703). In the 13 noncomparative studies, 23 patients underwent MMS (pooled LR estimate: 11.07%; 95% CI: 3.22%-31.81%) and 140 patients underwent NUE (pooled LR estimate:8.04%, 95% CI: 4.43%-14.16%). The difference in LR rate between MMS, NUE, and amputation was not statistically significant ( p = .578). CONCLUSION: Local recurrence of nail/subungual MIS in cases treated with MMS was not statistically different than in cases treated with NUE and was comparable to amputation. Further studies investigating the use of MMS for the treatment of nail/subungual MIS are warranted.

The burden of alopecia areata: A scoping review focusing on quality of life, mental health and work productivity.

Alopecia areata (AA) is a common inflammatory autoimmune disease of the hair which can have a significant negative impact on quality of life (QoL), mental health and productivity. The aim of this scoping review is to elucidate the burden of AA focusing on these three realms. Inclusion criteria included all original manuscripts with no restriction on study type or statistical method written in English (or having an English abstract). For QoL 40 articles were included, 85 for psychiatric comorbidities, and 9 for work/school absenteeism/presenteeism mostly consisting of cross-sectional and observational cohort studies. QoL impairment was detected in over 75% of patients and up to one-third reported extremely severe QoL impairments. Specific QoL dimensions with the greatest impact were embarrassment, social functioning, as well as shopping and/or housework. Cross-sectional studies assessing the psychological burden of adult patients with AA found that the presence of signs of anxiety and/or depression ranged from 30% to 68% and affected all age groups. Rates of work absenteeism and unemployment were significantly higher in AA patients compared to healthy controls. Up to 62% reported making major life decisions including relationships, education and career based on their AA. Additionally, the extensive camouflage techniques and time lost from work led to a strong financial burden for patients and the numerous physician visits added to the healthcare costs. The overall impact of AA stretches much further than simply being an aesthetic concern and can negatively impact every part of an individual's life. An individualized approach and effective treatments will help reduce the psychosocial consequences and distress and return patients to their normal state of health.

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.

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.

Omalizumab for the Treatment of Bullous Pemphigoid: A Systematic Review of Efficacy and Safety.

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 <10 mg daily. Flare-ups occurred in 57.7% of patients upon discontinuation of omalizumab and/or steroid tapering, most patients recaptured response thereafter. Omalizumab was well tolerated by most patients. Omalizumab appears to be a promising treatment for BP with a good response rate and safety profile. However, several limitations were identified in current literature, and highlight the need for randomized controlled trials of omalizumab in BP.

Clinical Characteristics, Management, and Natural History of Chronic Inducible Urticaria in a Pediatric Cohort.

BACKGROUND: Some forms of chronic urticaria (CU) can be specifically attributed to a response to a definite trigger, referred to as chronic inducible urticaria (CIndU). We aimed to assess the demographics, clinical characteristics, comorbidities, natural history, and management of pediatric patients with CIndU. METHODS: Over a 6-year period, children presenting to the allergy clinic at the Montreal Children's Hospital (MCH) with CIndU were prospectively recruited. CU was defined as the presence of wheals and/or angioedema, occurring for at least 6 weeks. A standardized diagnostic test was used to establish the presence of a specific form of urticaria. Resolution was defined as the absence of hives for 1 year without treatment. RESULTS: Sixty-four patients presented with CIndU, of which 51.6% were male, with a median age of 12.5 (interquartile range 7.3, 15.9) years. Cold CU and cholinergic CU were the most common subtypes (60.3 and 41.3%, respectively). Basophil counts were undetectable in 48.4% of the cases, and C-reactive protein levels were elevated in 7.8% of patients. Of all cases, 71.4% were controlled with second-generation antihistamines. The resolution rate was of 45.3% (95% confidence interval 33.1-57.5%), based on per-protocol population within the 6-year course of the study. Resolution was more likely in patients who presented with well-controlled urticaria control test scores and elevated CD63 counts and in those suffering from thyroid comorbidity. CONCLUSION: The natural history of CIndU resolution in pediatric patients was relatively low and was associated with elevated CD63 levels, as well as thyroid comorbidity.

Beyond Skin Tumors: A Systematic Review of Mohs Micrographic Surgery in the Treatment of Deep Cutaneous Fungal Infections.

BACKGROUND: Deep cutaneous fungal infections (DCFIs) can cause significant morbidity in immunocompromised patients and often fail medical and standard surgical treatments because of significant subclinical extension. Although rarely considered in this setting, Mohs micrographic surgery (MMS) offers the advantages of comprehensive margin control and tissue conservation, which may be beneficial in the treatment of DCFIs that have failed standard treatment options. OBJECTIVE: To review the benefits, limitations, and practicality of MMS in patients with DCFIs. METHODS: A systematic review of PubMed and EMBASE was conducted to identify all cases of fungal skin lesions treated with MMS. RESULTS: Eight case reports were identified consisting of a total of 8 patients. A majority of patients had a predisposing comorbidity (75%), with the most common being a solid organ transplant (n = 3, 37.5%). The most commonly diagnosed fungal infection was phaeohyphomycosis (n = 5, 62.5%), followed by mucormycosis (n = 2, 25%). No recurrence or complication post-MMS was noted at a mean follow-up of 11.66 months. CONCLUSION: Although not a first-line treatment, MMS can be considered as an effective treatment alternative for DCFIs in cases of treatment failure and can be particularly helpful in areas where tissue conservation is imperative.

Risk of peanut- and tree-nut-induced anaphylaxis during Halloween, Easter and other cultural holidays in Canadian children.

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.

Prevalence of Hypersensitivity Reactions in Children Associated with Acetaminophen: A Systematic Review and Meta-Analysis.

BACKGROUND: Acetaminophen is the most commonly used antipyretic in children. However, there are limited data assessing hypersensitivity reactions related to acetaminophen usage. OBJECTIVES: To conduct a systematic review to characterize reported reactions to acetaminophen in adults and children, and perform a meta-analysis to assess the prevalence of acetaminophen hypersensitivity in children with a suspected acetaminophen allergy. METHODS: We performed a systematic review of studies reporting hypersensitivity reactions to acetaminophen by searching 2 electronic databases. From the selected studies, we included those assessing the prevalence of acetaminophen hypersensitivity by performing oral challenge in our meta-analysis. RESULTS: Eighty-five studies were included in the systematic review, assessing a total of 1,030 participants. Immediate (within 1 h of exposure) hypersensitivity reactions were reported in > 25% of the articles, while cutaneous nonimmediate reactions were similarly reported in about 25% of the articles. The remaining articles reported Steven-Johnson syndrome/toxic epidermal necrolysis, fixed drug eruptions, and cross-intolerance reactions. Five pediatric studies were included in our meta-analysis. The prevalence of acetaminophen hypersensitivity reaction among children undergoing oral challenge was 10.1% (95% confidence interval 4.5-15.5). CONCLUSION: Future studies assessing the risk of immediate and nonimmediate hypersensitivity reactions to acetaminophen and elucidating the mechanism of acetaminophen hypersensitivity reactions are required.

Short- and long-term management of cases of venom-induced anaphylaxis is suboptimal.

BACKGROUND: Venom-induced anaphylaxis (VIA) accounts for severe reactions. However, little is known about the short- and long-term management of VIA patients. OBJECTIVE: To assess the short- and long-term management of VIA. METHODS: Using a national anaphylaxis registry (C-CARE), we identified VIA cases presenting to emergency departments in Montreal and to emergency medical services (EMSs) in western Quebec over a 4-year period. Data were collected on clinical characteristics, triggers, and management. Consenting patients were contacted annually regarding long-term management. Univariate and multivariate logistic regressions were used to identify factors associated with epinephrine use, allergist assessment, and administration of immunotherapy. RESULTS: Between June 2013 and May 2017, 115 VIA cases were identified. Epinephrine was administered to 63.5% (95% confidence interval [CI], 53.9%-72.1%) of all VIA cases by a health care professional. Treatment of reactions without epinephrine was more likely in reactions occurring at home and in nonsevere cases (no hypotension, hypoxia, or loss of consciousness). Among 48 patients who responded to a follow-up questionnaire, 95.8% (95% CI, 84.6%-99.3%) were prescribed epinephrine auto-injector, 68.8% (95% CI, 53.6%-80.9%) saw an allergist who confirmed the allergy in 63.6% of cases, and 81.0% of those with positive testing were administered immunotherapy. Among cases with follow-up, seeing an allergist was less likely in patients with known ischemic heart disease. CONCLUSION: Almost 30% of patients with suspected VIA did not see an allergist, only two thirds of those seeing an allergist had allergy confirmation, and almost one fifth of those with confirmed allergy did not receive immunotherapy. Educational programs are needed to bridge this knowledge-to-action gap.