Evaluation of Prehospital Management in a Canadian Emergency Department Anaphylaxis Cohort

Evidence-based use of epinephrine in anaphylaxis

PURPOSE OF REVIEW

Epinephrine is the first line treatment for anaphylaxis, however, there are limited data to support this. This review examines data surrounding evidence for the use of epinephrine in anaphylaxis, data on prescription for and use of epinephrine autoinjectors, and data examining newer routes of delivery of epinephrine; with a focus on recent publications over the past few years.

RECENT FINDINGS

With recent epidemiologic studies of anaphylaxis and new forms of epinephrine being studied, new data on the effects of epinephrine are aiding in the understanding of epinephrine's effects and the shortcomings of epinephrine both in its effect and utility in the real world.

SUMMARY

Epinephrine is still considered the first line therapy for anaphylaxis, and we are starting to have a better understanding of its effects in both healthy patients and those with anaphylaxis.

Outcomes associated with prehospital epinephrine in adult and pediatric patients with anaphylaxis

BACKGROUND

Prompt epinephrine administration is important to improve outcomes in anaphylaxis.

OBJECTIVE

To assess the impact of prehospital epinephrine on clinical outcomes of hospital admission, biphasic reactions, and emergency department (ED) length of stay (LOS) in a cohort of ED patients who had anaphylaxis including both children and adults.

METHODS

We conducted a single-center prospective and retrospective cohort study of patients who had anaphylaxis from April 2008 to December 2022. Associations between prehospital epinephrine administration with biphasic reactions and ED LOS were assessed with univariable models and the association with ED disposition was assessed with both univariable and multivariable logistic regression.

RESULTS

A total of 1107 patient visits were included for analysis. The median patient age was 29 (IQR: 14-50), 593 (53.6%) patients were of female sex, and 366 (33.1%) were younger than 18 years of age. Patients in the prehospital epinephrine group were also less likely to experience a biphasic reaction (5.4% vs 9.3%; odds ratio [OR] 0.56, 95% CI: 0.34-0.92) and had a decreased ED LOS (median 4.0 hours vs 4.7 hours). There was no difference in hospital admission between patients with and without prehospital epinephrine in both the univariable (19.5% vs 15.7%; OR 1.30, 95% CI: 0.94-1.79) and multivariable (adjusted OR 1.08, 95% CI: 0.71-1.64) models.

CONCLUSION

Prehospital epinephrine administration reduced the odds of a biphasic reaction and decreased ED LOS but did not reduce hospitalization in this cohort of ED patients who had anaphylaxis. Our findings suggest that timely administration of prehospital epinephrine is associated with improved patient outcomes.

Management of Severe Allergic-Like Contrast Media Reactions: Pitfalls and Strategies, From the AJR Special Series on Contrast Media

Adverse reactions to contrast media, although uncommon, are often high-acuity events and potentially life-threatening. Nonetheless, these events are treatable, and radiologists may be called on to manage a contrast media reaction. However, because these events are infrequent, they are prone to management errors. This Special Series Review highlights common pitfalls and practical tips for the management of acute contrast media reactions in children and adults. Recognition of frequent management errors and implementation of the mitigation strategies presented can ameliorate risk and improve patient outcomes. These measures include proper training regarding reaction management and medication administration, the prompt use of intramuscular epinephrine autoinjectors whenever a severe allergic-like reaction is suspected, the use of visual aids for quick reference in the setting of a reaction, and the recognition of adverse events that are not allergic-like reactions, which commonly require only supportive care.

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.

Protective role of protease-activated receptor-2 in anaphylaxis model mice

Anaphylaxis is a severe life-threatening hypersensitivity reaction induced by mast cell degranulation. Among the various mediators of mast cells, little is known about the role of tryptase. Therefore, we aimed to elucidate the role of protease-activating receptor-2 (PAR-2), a receptor activated by tryptase, in murine anaphylactic models using PAR-2-deficient mice and newly generated tryptase-deficient mice. Anaphylaxis was induced by IgE-dependent and IgE-independent mast cell degranulation in mice. PAR-2 deficiency exacerbated the decrease in body temperature and hypotension during anaphylaxis; however, the number of skin mast cells, degree of mast cell degranulation, and systemic and local vascular hyperpermeability were comparable in PAR-2 knockout and wild-type mice. Nitric oxide, which is produced by endothelial nitric oxide synthase (eNOS), is an indispensable vasodilator in anaphylaxis. In the lungs of anaphylactic mice, PAR-2 deficiency promoted eNOS expression and phosphorylation, suggesting a protective effect of PAR-2 against anaphylaxis by downregulating eNOS activation and expression. Based on the hypothesis that the ligand for PAR-2 in anaphylaxis is mast cell tryptase, tryptase-deficient mice were generated using CRISPR-Cas9. In wild-type mice, the PAR-2 antagonist exacerbated the body temperature drop due to anaphylaxis; however, the effect of the PAR-2 antagonist was abolished in tryptase-deficient mice. These results suggest that tryptase is a possible ligand of PAR-2 in anaphylaxis and that the tryptase/PAR-2 pathway attenuates the anaphylactic response in mice.

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.

Prehospital and In-Hospital Treatment with Adrenaline and Related Prognosis in Anaphylaxis Patients

INTRODUCTION

Although intramuscular adrenaline is the recommended first-line treatment for anaphylaxis, not all patients receive this treatment. The consequences in daily clinical practice are sparsely described. This study aimed to investigate the treatment administered to anaphylactic patients and the related prognosis.

METHODS

A retrospective register-based study of patients with anaphylaxis referred to the allergy centre, Odense University Hospital (2019-2021). Each patient's medical records were reviewed for contacts with the emergency departments and the prehospital emergency medical service in the Region of Southern Denmark. The World Allergy Organization (WAO) grading system was used to assess the severity of prehospital and in-hospital anaphylaxis. Furthermore, the treatment administered to the patients was registered.

RESULTS

In total, 315 patients were included. The prehospital system had contact with 256 of these patients (two were released prehospitally following treatment and 12 patients had insufficient data to assess anaphylaxis). Of the remaining 242 patients, 115 had anaphylaxis prehospitally (WAO grades 3-5); 59% (67/115) received adrenaline. Among the 67 patients who received prehospital adrenaline, 9 patients (13.4%; 95% CI: 6.3-24.0%) still had anaphylaxis at arrival at the emergency department. Of the 48 patients that were not treated with prehospital adrenaline, 17 patients (35.5%; 95% CI: 22.1-50.5) had anaphylaxis at the arrival to the emergency department. Among the 127 patients without prehospital anaphylaxis (WAO grades 0-2), 22 patients (18.2%; 95% CI: 11.8-26.2%) who did not receive prehospital adrenaline had anaphylaxis at arrival to the emergency department, while none of the 6 patients treated prehospitally with adrenaline had anaphylaxis.

CONCLUSION

Omission of prehospital adrenaline in anaphylactic patients is associated with more severe anaphylactic symptoms at arrival to the hospital. Adrenaline treatment remains suboptimal since only half of the patients received prehospital adrenaline and only 1 out of 4 patients, with clinical signs of anaphylaxis, received adrenaline inside the hospital.

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.

Preventing food allergy fatalities

Fatal anaphylaxis to food is thankfully rare, but every death is a potentially avoidable tragedy. Usually, there will be a coronial inquest to establish the 'how and why' for each death. Reviewing these food allergy-related deaths identifies a number of common themes and risk factors. While some are non-modifiable (such as age, gender and ethnicity), others are and include delayed epinephrine administration and communication difficulties in allergen avoidance. This review highlights the key messages in food allergy-related fatality prevention for healthcare professionals and patients alike, and where available, we explain the evidence behind such recommendations. We describe the data behind the good practice points to facilitate their adoption in routine practice without generating additional anxiety for what is a comparatively rare event. We also propose an information leaflet for patients and carers, developed with patients and endorsed by two major allergy charities, to facilitate dissemination of the recommendations in this review.

Anaphylaxis management in a French pediatric emergency department: Lessons from the ANA-PED study

BACKGROUND

Anaphylaxis is a serious systemic hypersensitivity reaction that requires immediate recognition and prompt administration of epinephrine/adrenaline. The present study aimed to assess the appropriateness of epinephrine/adrenaline use in children identified as allergic by physicians in the emergency department (ED) at the time of the reaction, and to identify factors that are possibly associated with epinephrine/adrenaline administration, auto-injector prescription, and further referral to an allergist.

METHODS

We performed a retrospective cross-sectional study at the pediatric ED of the University Hospital of Montpellier, France. We included all consecutive children who attended the ED between 2016 and 2020 with an allergy-related diagnosis at discharge.

RESULTS

We included 1056 allergy-related visits, including 224 (21.2%) with a diagnosis of anaphylaxis at discharge; only 17.0% of them received an epinephrine/adrenaline injection, and 57.1% consulted an allergist after the acute episode. An auto-injector was prescribed to 63 (28.1%) patients at discharge from the ED. Besides the severity of the clinical presentation, factors associated with a guidelines-based management of the anaphylactic reaction and with an increased administration rate of epinephrine/adrenaline included presence of asthma symptoms and presence of extended skin reactions.

CONCLUSIONS

Our study underlines persistent gaps in the management of pediatric anaphylaxis in ED, focusing on hereby identified levers. By disseminating current knowledge and guidelines on anaphylaxis and allergies, specialists could work together with emergency physicians to establish effective management algorithms and improve anaphylaxis management and care pathways for children experiencing allergic reactions, especially anaphylaxis.

TRAIL REGISTRATION

Clinical Trials, number NCT05112367.

Contextual community epinephrine prescribing: Is more always better?

OBJECTIVE

Prompt administration of epinephrine is first-line management of anaphylaxis. Although severe anaphylaxis may require more than 1 epinephrine dose, multiple epinephrine device packs may not be necessary for all patients at risk for allergic reactions.

DATA SOURCES

A narrative review was used to describe key considerations to contextualize community epinephrine prescribing.

RESULTS

Anaphylaxis has a lifetime prevalence of 1.6% to 5.1%. Meeting diagnostic criteria for anaphylaxis is not required for epinephrine treatment of a severe allergic reaction. A "1-2-3" approach to anaphylaxis treatment is important to clearly relay central management steps: promptly administer a first dose of intramuscular epinephrine with proper positioning, and activate emergency medical services if immediate symptom resolution does not occur; consider a second dose of intramuscular epinephrine with consideration of oxygen administration and intravenous fluid if initial epinephrine response is not adequate; and consider a third intramuscular epinephrine dose together with consideration of intravenous fluid support and oxygen for continued lack of appropriate response. Although multiple epinephrine doses may be required to treat severe anaphylaxis, 90% of anaphylaxis cases do not require more than 1 epinephrine dose. A universal requirement for multiple epinephrine devices in patients without a history of anaphylaxis is not cost-effective. Patients without a history of anaphylaxis may be managed without multiple device prescriptions within a patient-preference sensitive paradigm of care.

CONCLUSION

Anaphylaxis prevention involves appropriate education to avoid allergen triggers, recognize symptoms of an allergic reaction, rapidly access and administer intramuscular epinephrine, and appropriately activate emergency medical services when needed. For patients with previous anaphylaxis, particularly those who have required more than 1 dose of epinephrine to treat an allergic reaction, possessing multiple epinephrine devices is an important part of managing community anaphylaxis risk.

Refractory Anaphylaxis: A New Entity for Severe Anaphylaxis

Anaphylaxis reactions lie on a spectrum of severity, ranging from relatively mild lower respiratory involvement (depending on the definition of anaphylaxis used) to more severe reactions that are refractory to initial treatment with epinephrine and may rarely cause death. A variety of grading scales exist to characterize severe reactions, but there is a lack of consensus about the optimal approach to define severity. More recently, a new entity called refractory anaphylaxis (RA) has emerged in the literature, characterized by the persistence of anaphylaxis despite initial epinephrine treatment. However, slightly different definitions have been proposed to date. In this Rostrum, we review these definitions as well as data relating to epidemiology, elicitors, risk factors, and management of RA. We propose a need to align the different definitions for RA, to improve epidemiological surveillance, advance our understanding of the pathophysiology of RA, and optimize management strategies to reduce morbidity and mortality.

Epinephrine treatment of food-induced and other cause anaphylaxis in United States and Canadian Emergency Departments: a systematic review and meta-analysis

INTRODUCTION

Studies from more than 10 years ago showed epinephrine treatment of food-induced anaphylaxis in the emergency department (ED) was unacceptably low. We investigated whether epinephrine treatment of food-induced and other cause anaphylaxis in United States and Canadian EDs has changed over time.

METHODS

Guided by a health sciences librarian, we performed a systematic search in Medline, Embase, and Web of Science on 11 January 2023. We included observational studies that reported epinephrine use to treat anaphylaxis in the ED. We stratified by anaphylaxis etiology (food-, venom-, medication-induced, or any cause). Associations between year and epinephrine use were tested using Spearman correlation and proportional meta-analysis.

RESULTS

Of 2458 records identified in our initial search, 40 met inclusion criteria. Of these, 14 examined food-induced, 4 venom-induced, 0 medication-induced, and 24 any cause anaphylaxis. For epinephrine treatment of food-induced anaphylaxis in the ED, among studies using similar definition of anaphylaxis, meta-analysis showed a pooled value of 20.7% (95% CI 17.8, 23.8) for studies performed >10 years ago and 45.1% (95% CI 38.4, 52.0) from those in the last 10 years. For anaphylaxis of any cause, there was no change over time, with a pooled value of 45.0% (95% CI 39.8, 50.3) over the last 10 years.

DISCUSSION

Epinephrine treatment of food-induced anaphylaxis in the ED has increased over time. There was no clear change for anaphylaxis of any cause. Over the last 10 years, approximately 45% of ED patients with anaphylaxis received epinephrine. A limitation of the evidence is heterogeneity in anaphylaxis definitions.

Cofactors in food anaphylaxis in adults

Around 25% to 50% of food-induced allergic reactions in adults cause anaphylaxis, and epidemiologic evidence suggests that food is the most common cause of anaphylaxis. Reaction severity is unpredictable, and patients will often experience reactions of variable severity, even to an identical exposure (both dose and allergen). A common explanation for this phenomenon has been the impact of "cofactors"-factors that might contribute to reaction severity independent of the allergen exposure. Cofactors can influence reaction severity in 2 ways: either by reducing the reaction threshold (ie, the dose needed to trigger any symptoms) so that patients have no symptoms in the absence of the cofactor and only react with the cofactor present, or by increasing reaction severity such that individuals have only mild symptoms in the absence of the cofactor, but a more severe reaction when the cofactor is present. Indeed, the same patient may have reactions with different cofactors or even need more than one cofactor to develop a severe reaction. Cofactors reportedly play a role in approximately 30% of anaphylaxis reactions in adults. Exercise, nonsteroidal, anti-inflammatory drugs, alcohol, and sleep deprivation are the most frequent cofactors reported. Routine evaluation of the possible involvement of cofactors is essential in managing patients with food anaphylaxis: in patients with a suggestive history but a negative oral food challenge, cofactors should be taken into account to provide appropriate advice to reduce the risk of future anaphylaxis.

Retrospective review of diphenhydramine vs diphenhydramine plus glucocorticoid for the treatment of allergic reaction in cats

OBJECTIVES

The aims of the present study were to report the outcomes of treating allergic reactions in cats with diphenhydramine vs diphenhydramine plus glucocorticoid and to determine whether signs recurred or additional veterinary intervention was needed in the days after initial treatment.

METHODS

This retrospective study evaluated 73 cats treated for allergic reaction with diphenhydramine alone or in combination with a glucocorticoid at a 24 h emergency and specialty referral veterinary hospital between 1 January 2012 and 31 March 2021.

RESULTS

In total, 44 cats were treated with diphenhydramine alone, and 29 were treated with diphenhydramine plus dexamethasone sodium phosphate. The inciting cause was known or highly suspected in 50 patients. Vaccines were the most common (31 patients), followed by insect envenomation (17 cases). No cat in either group progressed to anaphylaxis. There was no difference in resolution of clinical signs between the groups. Follow-up contact was successfully made with 40/73 cat owners. All 40 cats were alive. Eight had persistent signs. There was no difference in the number of cats with persistent signs between groups. Five cats required additional treatment after the initial emergency visit. There was no difference between the two groups for persistent signs at follow-up.

CONCLUSIONS AND RELEVANCE

There was no difference in measured outcomes between cats treated with diphenhydramine alone vs those treated with a glucocorticoid in addition to diphenhydramine in this population. The ideal treatment for allergic reactions is unknown. Based on currently available data in human and veterinary literature, glucocorticoids are not indicated to treat acute allergic reactions. The role of antihistamines as part of a symptomatic supportive treatment plan to shorten the duration of signs is unclear at this time and may be considered.

The Japanese Epidemiologic Study for Perioperative Anaphylaxis, a prospective nationwide study: clinical signs, severity, and therapeutic agents

BACKGROUND

Diagnosis of perioperative anaphylaxis is difficult because of its non-specific and variable signs and symptoms. Therapeutic agents used to treat anaphylaxis and anaesthesiologist responses also vary depending on the case, which might affect outcomes; however, only a few studies have focused on these factors.

METHODS

This prospective study of perioperative anaphylaxis, a part of the Japanese Epidemiologic Study for Perioperative Anaphylaxis, investigated the clinical signs, its severity, therapeutic drugs, epinephrine administration, and anaesthesiologist responses in cases of perioperative anaphylaxis to assess trends and variability. Shock index was used to assess severity of cardiovascular collapse.

RESULTS

In 43 patients analysed in this study, cardiovascular signs (88.4%) were the most frequent, followed by skin (81.4%) and respiratory signs (60.5%). The presence of signs increased during the clinical course. The median time from the first signs to diagnosis of anaphylaxis was 10 (5.0-17.8) min. The rates of epinephrine use were 30.2% (unused), 48.8% (i.v.), and 20.9% (i.m.). The median time from diagnosis of anaphylaxis to epinephrine administration was 7 (inter-quartile range: 1.5-8.0) min. Antihistamines and corticosteroids were each used in 69.8% of cases. The worst shock index was higher in patients who received i.v. epinephrine (2.77 [0.90] mean [standard deviation]) than in both no epinephrine use cases (1.35 [0.41]) and i.m. epinephrine cases (1.89 [0.77] (P<0.001]).

CONCLUSIONS

The clinical signs and treatments of perioperative anaphylaxis are variable, and the choice regarding epinephrine administration is based on symptom severity.

CLINICAL TRIAL REGISTRATION

UMIN000035350.

Temporal trends in anaphylaxis ED visits over the last decade and the effect of COVID-19 pandemic on these trends

BACKGROUND

Anaphylaxis is an acute systemic and potentially fatal allergic reaction. We evaluated trends in yearly rates of anaphylaxis in a pediatric Emergency Department (ED) in Montreal, Canada.

METHODS

A prospective and retrospective recruitment process was used to find families of children who had presented with anaphylaxis at the Montreal Children's Hospital between April 2011 and April 2021. Using a uniform recruitment form, data were collected. Anaphylaxis patterns were compared to clinical triggers using descriptive analysis.

RESULTS

Among 830,382 ED visits during the study period, 2726 (26% recruited prospectively) presented with anaphylaxis. The median age was 6 years (IQR: 0.2, 12.00), and 58.7% were males. The relative frequency of anaphylaxis cases doubled between 2011-2015, from 0.22% (95% CI, 0.19, 0.26) to 0.42 March 2020, the total absolute number of anaphylaxis cases and relative frequency declined by 24 cases per month (p < 0.05) and by 0.5% of ED visits (p < 0.05).

CONCLUSIONS

The rate of anaphylaxis has changed over the years, representing modifications in food introduction strategies or lifestyle changes. The decrease in the frequency of anaphylaxis presenting to the ED during the COVID pandemic may reflect decreased accidental exposures with reduced social gatherings, closed school, and reluctance to present to ED.

Varying Approaches to Management of IgE-Mediated Food Allergy in Children Around the World

Food allergy is a chronic disease that affects individuals of all ages and is a significant public health problem globally. This narrative overview examines clinical management strategies for IgE-mediated food allergy in children around the world to understand variations in practice. Information was drawn from clinical practice guidelines, recent research, the websites of professional and governmental bodies with expertise in food allergy, and clinical experts from a broad cross-section of geographical regions. The structure and delivery of clinical services, allergen avoidance and food labeling, and resources to support the management of allergic reactions in the community are discussed in detail. The adoption of emerging food immunotherapies is also explored. Wide variations in clinical management of food allergy were apparent across the different countries. Common themes were continuing issues with access to specialist care and recognition of the need to balance risk reduction with dietary and social restrictions to avoid unnecessary detrimental impacts on the quality of life of food allergy sufferers. Findings highlight the need for standardized presentation of practice and priorities, and may assist clinicians and researchers when engaging with government and funding agencies to address gaps.

Who Needs Epinephrine? Anaphylaxis, Autoinjectors, and Parachutes

International guidelines stipulate that intramuscular (IM) epinephrine (adrenaline) is the first-line treatment for anaphylaxis, with an established good safety profile. The availability of epinephrine autoinjectors (EAI) has greatly facilitated the lay administration of IM epinephrine in community settings. However, key areas of uncertainty remain around epinephrine usage. These include variations in prescribing EAI, what symptoms should prompt epinephrine administration, whether emergency medical services (EMS) need to be contacted after administration, and whether epinephrine administered via EAI reduces mortality from anaphylaxis or improves quality of life measures. We provide a balanced commentary on these issues. There is increasing recognition that a poor response to epinephrine, particularly after 2 doses, is a useful marker of severity and the need for urgent escalation. It is likely that patients who respond to a single epinephrine dose do not require EMS activation or emergency department transfer, but data are needed to demonstrate the safety of this approach. Lastly, patients at risk of anaphylaxis must be counseled against over-reliance on EAI alone.

Endpoints and Outcomes After Immunotherapy for Food Allergy: What Is Meaningful for Patients?

Multiple novel interventions for food allergy are currently at various stages of development with the goal of reducing or eliminating allergic reactions. However, the relative success of these therapeutics in achieving meaningful, long-term improvements to patients' lives is difficult to determine as there is currently very limited understanding of the degree of alignment between clinical trial efficacy endpoints and patient-centered outcomes. Furthermore, outcome measures used in clinical trials of food allergy immunotherapies vary widely, are often misinterpreted, and not necessarily consistent with what patients expect to achieve through treatment. This review aims to assist clinicians in critically interpreting outcomes reported in clinical trials and accurately communicating risks and outcomes to patients when practicing shared decision-making.

Peanut-Induced Anaphylaxis in Children: A Literature Review

Peanut allergy has become more common among children and is considered one of the most common triggers for fatal anaphylaxis. Treatment of symptoms during a reaction is only one aspect of managing anaphylaxis; other elements include rigorous dietary avoidance and education about settings that could put the patient at a high risk of unintentional exposure. We aimed to review the prevalence, mechanism, diagnosis, treatment, and emergency action of peanut-induced anaphylaxis among children. We used a web-based literature search using the advanced features of databases such as PubMed, Scopus, Directory of Open Access Journals (DOAJ), Embase, Google Scholar, and Cochrane electronic databases. The most common food to cause fatal anaphylaxis and a common cause of food allergies is peanuts. Over the past two years, our knowledge improved more about peanut allergens, their prevalence, causes, diagnoses, and treatments. The research cited in this review demonstrates that the peanut allergens are most closely associated with disease differ across cultures, that early oral peanut exposure may reduce the occurrence of peanut allergy while early non-oral exposure may have the opposite effect, that complement activation by peanut constituents appears to promote peanut-induced anaphylaxis, and that oral immunotherapy, anti-IgE antibody, and a herbal formulation are all demonstrating promise as treatments. To conclude, peanut allergies have increased frequently during the past 10 years, especially in Westernized nations. Given that peanut allergy poses a danger for fatal anaphylaxis, response management is crucial. The current standard of care for those with nut allergies comprises complete food avoidance and the administration of injectable epinephrine to treat systemic symptoms.

Impact of Reaction Setting on the Management, Severity, and Outcome of Pediatric Food-Induced Anaphylaxis: A Cross-Sectional Study

BACKGROUND

Prompt epinephrine autoinjector (EAI) use is the primary treatment for anaphylaxis. However, limited Canadian data exist on the impact of reaction location on EAI use for food-induced anaphylaxis (FIA).

OBJECTIVE

We sought to investigate the setting, management, and severity of pediatric FIA.

METHODS

We recruited children presenting with FIA from 11 Canadian emergency departments. Patient demographics and the setting, management, and symptoms of FIA were collected by standardized questionnaire. Factors associated with prehospital EAI use and reaction severity were determined by logistic regression.

RESULTS

We recruited 3,604 children; 60.2% were male and the median age was 5.0 years (interquartile range 1.8-11.0). Among cases with a known location of FIA (85.0%), home was the most common setting (68.1%), followed by school/daycare (12.8%), other locations (11.4%; eg, park, car), and restaurants (7.4%). In the prehospital setting, EAI was administered in 36.7% of reactions at home, 66.7% in school/daycare, 40.2% in other locations, and 44.5% in restaurants. Relative to reactions occurring at school/daycare, prehospital EAI use was less likely at home (adjusted odds ratio [aOR] 0.80; 95% CI 0.76-0.84), in restaurants (aOR 0.81; 95% CI 0.75-0.87), and in other settings (aOR 0.77; 95% CI 0.73-0.83), when data were adjusted for reaction severity, sex, age, comorbidities, and province. The FIA setting was not associated with reaction severity or hospitalization.

CONCLUSIONS

Prehospital EAI use was higher at school/daycare than in other settings, potentially owing to the presence of policies and training on FIA. Setting-specific interventions including educational programs and policies/laws mandating training and stocking an EAI may improve anaphylaxis recognition and treatment.

Overview of registries for anaphylaxis: a scoping review

OBJECTIVE

This review aimed to describe the scope and operational features of anaphylaxis registries, and to assess their contribution to improving knowledge of anaphylaxis and care of patients who experience anaphylaxis by measuring their research output.

INTRODUCTION

Structured data collection and reporting systems, such as registries, are needed to better understand the burden of anaphylaxis and to protect the growing number of patients with severe allergy. There is a need to characterize current anaphylaxis registries to identify their value in anaphylaxis surveillance, management, and research. Information synthesized in this review will provide knowledge on benefits and gaps in current registries, which may inform the implementation and global standardization of future anaphylaxis reporting systems.

INCLUSION CRITERIA

This scoping review considered literature describing registries worldwide that enroll patients who have experienced anaphylaxis. Published and gray literature sources were included if they described the scope and operational features of anaphylaxis registries.

METHODS

This review followed the JBI methodology for scoping reviews. Embase, MEDLINE, Scopus, and CINAHL were searched for relevant articles. Identified keywords and index terms were adapted for searches of gray literature sources, using Google advanced search functions. Only full-text studies in English were considered for inclusion. Two independent reviewers conducted title and abstract screening and those that did not meet the inclusion criteria were excluded. The full text of potentially relevant articles were retrieved; full-text screening and data extraction were also conducted by two independent reviewers. Any discrepancies were resolved through discussion or with a third reviewer. Tables and a narrative summary were used to describe and compare the scope and features (eg, inclusion criteria, patient demographics, clinical symptoms) of the identified anaphylaxis registries, and to outline their output to assess their contribution to research and clinical practice for anaphylaxis.

RESULTS

A total of 77 full-text publications and eight gray literature sources were used to extract data. The literature search identified 19 anaphylaxis registries, with sites in 28 countries including Europe, the United Kingdom, Canada, the United States, Korea, and Australia. The main purposes of the identified registries were to collect clinical data for research; provide clinical support tools to improve patient care; and operate as allergen surveillance systems to protect the wider community with allergies. Differences in inclusion and health care settings exist, with 11 collecting data on anaphylaxis of any cause, two on food reactions alone, three on fatal anaphylaxis, one on perioperative anaphylaxis, and two on allergic reactions (including anaphylaxis). Five registries enroll cases in allergy centers, five in hospital settings, one in schools, and others target a combination of general practitioners, specialists in emergency departments, and other relevant hospital departments and allergy outpatient clinics. Only three registries operate under a mandatory framework. A total of 57 publications were considered research outputs from registries. All registries except two have published studies from collected data, with the greatest number of articles published from 2019 to the present. Publications mostly addressed questions regarding demographic profile, causes and cofactors, severity, fatal reactions, and gaps in management.

CONCLUSIONS

This review demonstrated that anaphylaxis registries differ in their scope and operation, having been established for different purposes. Importantly, registries have contributed significantly to research, which has highlighted gaps in anaphylaxis management, provoking allergens, and informed targets for prevention for severe and fatal events. Beyond this, registries relay information about anaphylaxis to clinicians and regulatory bodies to improve patient care and protect the community. The ability to link registry data with other health datasets, standardization of data across registries, and incorporation of clinical care indicators to promote quality health care across the health system represent important targets for future systems.

Canadian Anaphylaxis Network-Predicting Recurrence after Emergency Presentation for Allergic REaction (CAN-PREPARE): a prospective, cohort study protocol

INTRODUCTION

Anaphylaxis is a severe, potentially fatal multiorgan system manifestation of an allergic reaction. The highest incidence of anaphylaxis is in children and adolescents. Biphasic anaphylaxis (BA) is defined as the recurrence of allergic symptoms after resolution of an initial reaction. It has been reported to occur in 10%-20% of cases within 1-48 hours from the onset of the initial reaction. The dilemma for physicians is determining which patients with resolved anaphylaxis should be observed for BA and for how long. Guidelines for duration of postanaphylaxis monitoring vary, are based on limited evidence and can have unintended negative impacts on patient safety, quality of life and healthcare resources. The objectives of this study are to derive a prognostic model for BA and to develop a risk-scoring system that informs disposition decisions of children who present to emergency departments (ED) with anaphylaxis.

METHODS AND ANALYSIS

This prospective multicentre cohort study will enrol 1682 patients from seven paediatric EDs that are members of the Paediatric Emergency Research Canada network. We will enrol patients younger than 18 years of age with an allergic reaction meeting anaphylaxis diagnostic criteria. Trained ED research assistants will screen, obtain consent and prospectively collect study data. Research assistants will follow patients during their ED visit and ascertain, in conjunction with the medical team, if the patient develops BA. A standardised follow-up survey conducted following study enrolment will determine if a biphasic reaction occurred after ED disposition. Model development will conform to the broad principles of the PROGRESS (Prognosis Research Strategy) framework and reporting will follow the Transparent Reporting of a multivariable prediction model for Individual Prognosis or Diagnosis Statement.

ETHICS AND DISSEMINATION

Ethics approval has been received from all participating centres. Our dissemination plan focuses on informing clinicians, policy makers and parents of the results through publication in peer-reviewed journals and broadcasting on multiple media platforms.

TRIAL REGISTRATION NUMBER

NCT05135377.

Risk factors for severe reactions in food allergy: Rapid evidence review with meta-analysis

This rapid review summarizes the most up to date evidence about the risk factors for severe food-induced allergic reactions. We searched three bibliographic databases for studies published between January 2010 and August 2021. We included 88 studies and synthesized the evidence narratively, undertaking meta-analysis where appropriate. Significant uncertainties remain with respect to the prediction of severe reactions, both anaphylaxis and/or severe anaphylaxis refractory to treatment. Prior anaphylaxis, an asthma diagnosis, IgE sensitization or basophil activation tests are not good predictors. Some molecular allergology markers may be helpful. Hospital presentations for anaphylaxis are highest in young children, yet this age group appears at lower risk of severe outcomes. Risk of severe outcomes is greatest in adolescence and young adulthood, but the contribution of risk taking behaviour in contributing to severe outcomes is unclear. Evidence for an impact of cofactors on severity is lacking, although food-dependent exercise-induced anaphylaxis may be an exception. Some medications such as beta-blockers or ACE inhibitors may increase severity, but appear less important than age as a factor in life-threatening reactions. The relationship between dose of exposure and severity is unclear. Delays in symptom recognition and anaphylaxis treatment have been associated with more severe outcomes. An absence of prior anaphylaxis does not exclude its future risk.

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.

Acute At-Home Management of Anaphylaxis: 911: What Is the Emergency?

The appropriate at-home management of anaphylaxis begins with patient education on recognition and treatment, especially when and how to use epinephrine. Delayed administration of epinephrine as well as having severe symptoms and needing multiple doses of epinephrine to treat symptoms are risk factors for biphasic anaphylaxis. The successful implementation of at-home management of anaphylaxis requires appropriate patient selection and an algorithmic approach that recommends activation of emergency medical services (EMS) when the patient does not adequately respond to at-home administration of epinephrine or there are extenuating patient-related circumstances. Fortunately, approximately 98% of anaphylactic episodes respond to 2 or fewer doses of epinephrine, the standard prescription used for epinephrine autoinjectors; fatal anaphylaxis is very rare, as low as 0.002 deaths/million person-years; and biphasic reactions are uncommon (∼5%), and only extremely rarely lethal. Thus, most common concerns leading to recommended EMS activation and emergency department visits after epinephrine administration are generally unsubstantiated. Furthermore, emergency department visits do not always lead to better treatment and drive health care costs higher. Open communications with patients and families regarding risks and benefits of at-home management and observation versus EMS activation and emergency department evaluation after epinephrine administration for anaphylaxis are essential. However, we believe the data indicate that it is time to reconsider the often used and taught approach that recommends EMS activation whenever epinephrine is used.

Emergency treatment of anaphylaxis: concise clinical guidance

Anaphylaxis is a serious systemic hypersensitivity reaction that is usually rapid in onset and may cause death. It is characterised by the rapid development of airway and/or breathing and/or circulation problems. Intramuscular adrenaline is the most important treatment, although, even in healthcare settings, many patients do not receive this intervention contrary to guidelines. The Resuscitation Council UK published an updated guideline in 2021 with some significant changes in recognition, management, observation and follow-up of patients with anaphylaxis. This is a concise version of the updated guideline.

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.

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

BACKGROUND

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

OBJECTIVE

To assess FA-related direct (healthcare and out-of-pocket) and indirect (lost productivity) costs and their determinants in Canadian children and adults self-reporting FA.

METHODS

FA-individuals self-reporting a convincing history or physician diagnosis were recruited through FA registries, an anaphylaxis registry, and advocacy associations, and electronically surveyed regarding FA-related healthcare use, out-of-pocket expenditures, and time lost from paid and unpaid labor. Direct and indirect costs (2020 Canadian dollars [CAD]) were stratified on severe reaction vs mild, moderate or no reaction, and children vs adults; multivariate regressions assessed the association between costs and sociodemographic and disease characteristics.

RESULTS

Between May 2018 and July 2019, 2692 eligible individuals responded (2189 convincing history and 503 physician diagnosis only); 1020 experienced a severe reaction; 1752 were children. Per FA-individual, annual healthcare, out-of-pocket, and indirect costs were $1267, $2136, and $7950. Those with a severe reaction had higher healthcare and out-of-pocket costs than those with mild, moderate or no reaction. FA-children vs FA-adults had higher healthcare and out-of-pocket costs, and lower indirect costs. Multivariate results showed that lower age, a severe reaction ever, multiple FAs, and fair or poor general health were associated with higher healthcare and out-of-pocket costs. Higher age, lower household education and income, and fair or poor general health were associated with higher indirect costs.

CONCLUSION

The economic burden of FA in Canada is substantial, particularly for those with a severe reaction ever, multiple FAs, and fair or poor general health. It is crucial that those most adversely affected are allocated appropriate resources to support disease management.

A Clinical Practice Guideline for the Emergency Management of Anaphylaxis (2020)

Background: For anaphylaxis, a life-threatening allergic reaction, the incidence rate was presented to have increased from the beginning of the 21st century. Underdiagnosis and undertreatment of anaphylaxis are public health concerns. Objective: This guideline aimed to provide high-quality and evidence-based recommendations for the emergency management of anaphylaxis. Method: The panel of health professionals from fifteen medical areas selected twenty-five clinical questions and formulated the recommendations with the supervision of four methodologists. We collected evidence by conducting systematic literature retrieval and using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. Results: This guideline made twenty-five recommendations that covered the diagnosis, preparation, emergency treatment, and post-emergency management of anaphylaxis. We recommended the use of a set of adapted diagnostic criteria from the American National Institute of Allergy and Infectious Diseases and the Food Allergy and Anaphylaxis Network (NIAID/FAAN), and developed a severity grading system that classified anaphylaxis into four grades. We recommended epinephrine as the first-line treatment, with specific doses and routes of administration for different severity of anaphylaxis or different conditions. Proper dosage is critical in the administration of epinephrine, and the monitor is important in the IV administration. Though there was only very low or low-quality evidence supported the use of glucocorticoids and H1 antagonists, we still weakly recommended them as second-line medications. We could not make a well-directed recommendation regarding premedication for preventing anaphylaxis since it is difficult to weigh the concerns and potential effects. Conclusion: For the emergency management of anaphylaxis we conclude that: • NIAID/FAAN diagnostic criteria and the four-tier grading system should be used for the diagnosis • Prompt and proper administration of epinephrine is critical.

EAACI guidelines: Anaphylaxis (2021 update)

Anaphylaxis is a clinical emergency which all healthcare professionals need to be able to recognize and manage. The European Academy of Allergy and Clinical Immunology Anaphylaxis multidisciplinary Task Force has updated the 2014 guideline. The guideline was developed using the AGREE II framework and the GRADE approach. The evidence was systematically reviewed and recommendations were created by weighing up benefits and harms. The guideline was peer-reviewed by external experts and reviewed in a public consultation. The use of clinical criteria to identify anaphylaxis is suggested with blood sampling for the later measurement of tryptase. The prompt use of intramuscular adrenaline as first-line management is recommended with the availability of adrenaline autoinjectors to patients in the community. Pharmacokinetic data should be provided for adrenaline autoinjector devices. Structured, comprehensive training for people at risk of anaphylaxis is recommended. Simulation training and visual prompts for healthcare professionals are suggested to improve the management of anaphylaxis. It is suggested that school policies reflect anaphylaxis guidelines. The evidence for the management of anaphylaxis remains mostly at a very low level. There is an urgent need to prioritize clinical trials with the potential to improve the management of patients at risk of anaphylaxis.

Safely Reducing Hospitalizations for Anaphylaxis in Children Through an Evidence-Based Guideline

BACKGROUND

Emergency department visits for anaphylaxis have increased considerably over the past few decades, especially among children. Despite this, anaphylaxis management remains highly variable and contributes to significant health care spending. On the basis of emerging evidence, in this quality improvement project we aimed to safely decrease hospitalization rates, increase the use of cetirizine, and decrease use of corticosteroids for children with anaphylaxis by December 31, 2019.

METHODS

A multipronged intervention strategy including a revised evidence-based guideline was implemented at a tertiary children's teaching hospital by using the Model for Improvement. Statistical process control was used to evaluate for changes in key measures. Length of stay and unplanned return visits within 72 hours were monitored as process and balancing measures, respectively. As a national comparison, hospitalization rates were compared with other hospitals' data from the Pediatric Health Information System.

RESULTS

Hospitalizations decreased significantly from 28.5% to 11.2% from preimplementation to implementation, and the balancing measure of 72-hour revisits was stable. The proportion of patients receiving cetirizine increased significantly from 4.2% to 59.7% and use of corticosteroids decreased significantly from 72.6% to 32.4% in patients without asthma. The proportion of patients meeting length of stay criteria increased from 53.3% to 59.9%. Hospitalization rates decreased nationally over time.

CONCLUSIONS

We reduced hospitalizations for anaphylaxis by 17.3% without concomitant increases in revisits, demonstrating that unnecessary hospitalizations can be safely avoided. The use of a local evidence-based guideline paired with close outcome monitoring and sustained messaging and feedback to clinicians can effectively improve anaphylaxis management.

Wilderness Medical Society Clinical Practice Guidelines on Anaphylaxis

The Wilderness Medical Society convened a panel to review the literature and develop evidence-based clinical practice guidelines on the treatment of anaphylaxis, with an emphasis on a field-based perspective. The review also included literature regarding the definition, epidemiology, clinical manifestations, and prevention of anaphylaxis. The increasing prevalence of food allergies in the United States raises concern for a corresponding rise in the incidence of anaphylaxis. Intramuscular epinephrine is the primary treatment for anaphylaxis and should be administered before adjunctive treatments such as antihistamines, corticosteroids, and inhaled β agonists. For outdoor schools and organizations, selecting a method to administer epinephrine in the field is based on considerations of cost, safety, and first responder training, as well as federal guidelines and state-specific laws.

Repeated adrenaline requirements for anaphylaxis

We examined the pattern of adrenaline administration in patients presenting with anaphylaxis. Forty-four percent required repeated adrenaline administration, among whom there had been greater cardiorespiratory compromise. Repeated administration was more frequent in males and older patients, and those triggered by insect sting or unknown cause; no other patient factors were identified. This study supports the provision of two adrenaline auto-injectors to all anaphylaxis patients.

CSACI position statement: transition recommendations on existing epinephrine autoinjectors

Epinephrine is the first line treatment for anaphylaxis, an acute potentially life-threatening allergic reaction. It is typically administered intramuscularly in the anterolateral thigh at a dose of 0.01 mg/kg of 1:1000 (1 mg/ml) solution to a maximum initial dose of 0.5 mg. Currently in Canada, epinephrine autoinjectors (EAI) are available in three doses, 0.15 mg, 0.30 mg, and 0.50 mg. There are currently no published studies comparing 0.3 mg and 0.5 mg EAIs in the paediatric or adult populations to compare clinical effectiveness. However, as weight increases above 30 kg, the percentage of the recommended 0.01 mg/kg epinephrine dose from an existing 0.3 mg EAI decreases resulting in potential underdosing. As such, The Canadian Society of Allergy and Immunology (CSACI) recommends that for those who weigh ≥ 45 kg, physicians could consider prescribing the 0.50 mg EAI based on shared decision making with patients.

Global patterns in anaphylaxis due to specific foods: A systematic review

BACKGROUND

There are increasing global data relating to prevalence of food allergy and food-induced anaphylaxis; however, this is often based on surrogate measures of sensitization rather than objective symptoms at food challenge. In terms of protecting food-allergic consumers from reactions, to our knowledge, there has been no global survey assessing geographic differences in the proportion of anaphylaxis triggered by specific foods.

OBJECTIVE

We sought to identify common triggers for food-induced anaphylaxis and how these vary from country to country.

METHODS

Systematic review of relevant reports published between January 2010 and November 2020. Results were reported following PRISMA guidelines. Publications were screened and data extracted by 2 independent reviewers, and the risk of bias was assessed.

RESULTS

Sixty-five studies (encompassing 41 countries and all 6 regions as defined by the Food and Agriculture Organization of the United Nations) were included. Significant regional variations in the most common triggers of food anaphylaxis were seen; however, in general, there was good agreement between local legislative requirements for allergen disclosure and the most common allergens for each region or nation.

CONCLUSIONS

Local legislation for allergen disclosure generally reflects those allergens commonly responsible for food anaphylaxis. Cow's milk and crustaceans appear to cause a higher proportion of anaphylaxis compared to peanut in some regions.

Anaphylaxis: Epidemiology and Differential Diagnosis

Anaphylaxis-related emergency department (ED) visits and hospitalizations are increasing. Triggers for anaphylaxis include food, medications, and stinging insects. Idiopathic anaphylaxis accounts for 30% to 60% of cases of anaphylaxis in adults and up to 10% of cases in children with novel allergens such as galactose-α-1,3 galactose reclassifying these cases. Recent practice guidelines have recommended against the routine use of systemic corticosteroids and antihistamines for the prevention of biphasic reactions and recommend an extended observation, up to 6 hours, for those with risk factors for biphasic anaphylaxis and those with lack of access to epinephrine and to emergency medical services.

Idiopathic anaphylaxis: Diagnosis and management

Introduction: Idiopathic anaphylaxis (IA) is a diagnosis of exclusion and is based on the inability to identify a causal relationship between a trigger and an anaphylactic event, despite a detailed patient history and careful diagnostic assessment. The prevalence of IA among the subset of people who experienced anaphylaxis is challenging to estimate and varies widely, from 10 to 60%; most commonly noted is ∼20% in the adult anaphylactic population. Comorbid atopic conditions, such as food allergy, allergic rhinitis, and asthma, are present in up to 48% of patients with IA. Improved diagnostic technologies and an increased understanding of conditions that manifest with symptoms associated with anaphylaxis have improved the ability to determine a more accurate diagnosis for patients who may have been initially diagnosed with IA. Methods: Literature search was conducted on PubMed, Google Scholar and Embase. Results: Galactose-α-1,3-galactose (α-gal) allergy, mast cell disorders, and hereditary a-tryptasemia are a few differential diagnoses that should be considered in patients with IA. Unlike food allergy, when anaphylaxis occurs within minutes to 2 hours after allergen consumption, α-gal allergy is a 3-6-hour delayed immunoglobulin E-mediated anaphylactic reaction to a carbohydrate epitope found in red meat (e.g., beef, lamb, pork). The more recently described hereditary α-tryptasemia is an inherited autosomal dominant genetic trait caused by increased germline copies of tryptase human gene alpha-beta 1 (TPSAB1), which encodes α tryptase and is associated with elevated baseline serum tryptase. Acute management of IA consists of carrying an epinephrine autoinjector to be administered immediately at the first signs of anaphylaxis. Long-term management for IA with antihistamines and other agents aims to potentially reduce the frequency and severity of the anaphylactic reactions, although the evidence is limited. Biologics are potentially steroid-sparing for patients with IA; however, more research on IA therapies is needed. Conclusion: The lack of diagnostic criteria, finite treatment options, and intricacies of making a differential diagnosis make IA challenging for patients and clinicians to manage.

Use of multiple epinephrine doses in anaphylaxis: A systematic review and meta-analysis

BACKGROUND

Regulatory bodies recommend that all patients at risk of anaphylaxis be prescribed 2 epinephrine autoinjectors, which they should carry at all times. This is in contrast to some guidelines. The proportion of anaphylaxis reactions that are treated with multiple doses of epinephrine has not been systematically evaluated.

OBJECTIVE

Our aim was to undertake a systematic review and meta-analysis of published studies reporting epinephrine treatment for anaphylaxis in which data relating to the number of doses administered were available.

METHODS

We searched the Medline, Embase, and Cochrane databases for relevant studies reporting at least 10 anaphylaxis events (due to food or venom) from 1946 until January 2020. Data were extracted in duplicate for the meta-analysis, and the risk of bias was assessed. The study was registered under the PROSPERO identifier CRD42017069109.

RESULTS

A total of 86 studies (36,557 anaphylaxis events) met the inclusion criteria (20 of the studies [23%] were prospective studies; 64 [74%] reported reactions in the community, and 22 [26%] included food challenge data). Risk of bias was assessed as low in 50 studies. Overall, 7.7% of anaphylaxis events from any cause (95% CI = 6.4-9.1) were treated with multiple doses of epinephrine. When only epinephrine-treated reactions for which subsequent doses were administered by a health care professional were considered, 11.1% of food-induced reactions (95% CI = 9.4-13.2) and 17.1% of venom-induced reactions (95% CI = 11.3-25.0) were treated with more than 1 epinephrine dose. Heterogeneity was moderate to high in the meta-analyses, but at sensitivity analysis this estimate was not affected by study design or anaphylaxis definition.

CONCLUSION

Around 1 in 10 anaphylaxis reactions are treated with more than 1 dose of epinephrine.

Cardiopulmonary resuscitation in special circumstances

Cardiopulmonary resuscitation prioritises treatment for cardiac arrests from a primary cardiac cause, which make up the majority of treated cardiac arrests. Early chest compressions and, when indicated, a defibrillation shock from a bystander give the best chance of survival with a good neurological status. Cardiac arrest can also be caused by special circumstances, such as asphyxia, trauma, pulmonary embolism, accidental hypothermia, anaphylaxis, or COVID-19, and during pregnancy or perioperatively. Cardiac arrests in these circumstances represent an increasing proportion of all treated cardiac arrests, often have a preventable cause, and require additional interventions to correct a reversible cause during resuscitation. The evidence for treating these conditions is mostly of low or very low certainty and further studies are needed. Irrespective of the cause, treatments for cardiac arrest are time sensitive and most effective when given early-every minute counts.

Biologics as treatment options for anaphylaxis

PURPOSE OF REVIEW

To provide the most recent insights in the use of biologicals in the treatment of patients with anaphylaxis.

RECENT FINDINGS

There is evidence that biologics such as omalizumab may be safe and effective in preventing anaphylactic reactions in patients at high risk mainly because of severe food allergy or desensitization procedures to food, airborne allergen, drugs, or hymenoptera venom.

SUMMARY

Further knowledge will guide the adoption and implementation of any new therapy including biologics for anaphylaxis according to the stratification of risk/benefits.

Management of pediatric allergic reaction: Practice patterns of Canadian pediatric emergency physicians

OBJECTIVES

Anaphylaxis is a severe allergic reaction that can be life-threatening. The literature indicates that the incidence of anaphylaxis is increasing and that there are deficiencies in both recognition and management. We aimed to examine the magnitude of these gaps in Canadian pediatric emergency medicine (PEM).

METHODS

We conducted a self-administered survey of the Pediatric Emergency Research Canada (PERC) physician database. The survey tool was developed through a literature review to identify recurring themes of gaps in anaphylaxis diagnosis and management. The final tool contained four scenarios; three scenarios featured each of the National Institute of Allergy and Infectious Diseases (NIAID) anaphylaxis criteria, separately, and a fourth case of non-anaphylactic allergy. Multiple-choice questions associated with each scenario addressed diagnosis, management, and disposition. Additional questions focused on epinephrine prescribing, observation durations, and respondent demographics.

RESULTS

Of the 214 members invited to participate in the survey, 152 (71%) responded. Anaphylaxis was accurately recognized 93%, 82%, and 99% of the time for the NIAID criteria one through three, respectively. When anaphylaxis was recognized, epinephrine was prescribed for each case 96%, 95%, and 72% of the time, respectively. Of all respondents, 115 (76%) accurately diagnosed all three cases of anaphylaxis and 82 (54%) treated anaphylaxis with epinephrine each time it was indicated.

CONCLUSION

Most respondents recognized cases of anaphylaxis; however, a substantial number demonstrated gaps in management that may adversely impact this vulnerable population. The recognition of anaphylaxis without urticaria or pulmonary findings and treatment of anaphylaxis with epinephrine, where indicated, were the main gaps identified.

Factors influencing emergency department observation time following anaphylaxis: a systematic review

OBJECTIVE

Anaphylaxis is a condition that warrants an observation period after symptoms resolution to detect rare but life-threatening delayed complications. There is a need for evidence to identify patients who would benefit from prolonged observation time. The purpose of this review was to identify factors that may influence the need for longer observation in the emergency department.

METHODS

PubMed, Embase, EBM Review, and Cochrane Library were searched using controlled vocabulary and keywords to cover all relevant data. Titles, abstract, and full text were reviewed for inclusion and exclusion criteria. Data were extracted from the included articles regarding case definitions, prognosis, treatment and time factors, and recommended observation time. Factors linked to observation time or complications were tabulated and compared between studies.

RESULTS

The search retrieved 2443 citations of which 49 were included. Twenty-one were primary studies and were used to identify factors influencing observation time or complications. Biphasic anaphylaxis was the only adverse event that warranted prolonged observation. The five risk factors often associated with biphasic reactions were time to first epinephrine, history of anaphylaxis, symptom severity, number of epinephrine doses, and unknown trigger. Biphasic reactions happened mostly within the first 72 h with most severe reactions occurring earlier than the milder ones. Heterogeneity in the definition of biphasic anaphylaxis made comparisons challenging.

CONCLUSIONS

Observation time should be based on the provider's best estimation of the risk of biphasic anaphylaxis, although no single factor can predict their occurrence. The identified factors will allow the development of an early discharge screening tool.

[Cardiac arrest under special circumstances]

These guidelines of the European Resuscitation Council (ERC) Cardiac Arrest under Special Circumstances are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the modifications required for basic and advanced life support for the prevention and treatment of cardiac arrest under special circumstances; in particular, specific causes (hypoxia, trauma, anaphylaxis, sepsis, hypo-/hyperkalaemia and other electrolyte disorders, hypothermia, avalanche, hyperthermia and malignant hyperthermia, pulmonary embolism, coronary thrombosis, cardiac tamponade, tension pneumothorax, toxic agents), specific settings (operating room, cardiac surgery, cardiac catheterization laboratory, dialysis unit, dental clinics, transportation [in-flight, cruise ships], sport, drowning, mass casualty incidents), and specific patient groups (asthma and chronic obstructive pulmonary disease, neurological disease, morbid obesity, pregnancy).

[Paediatric Life Support]

The European Resuscitation Council (ERC) Paediatric Life Support (PLS) guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations of the International Liaison Committee on Resuscitation (ILCOR). This section provides guidelines on the management of critically ill or injured infants, children and adolescents before, during and after respiratory/cardiac arrest.

Evidence update for the treatment of anaphylaxis

The Resuscitation Council UK has updated its Guideline for healthcare providers on the Emergency treatment of anaphylaxis. As part of this process, an evidence review was undertaken by the Guideline Working Group, using an internationally-accepted approach for adoption, adaptation, and de novo guideline development based on the Grading of Recommendations Assessment, Development and Evaluation (GRADE) evidence to decision (EtD) framework, referred to as GRADE-ADOLOPMENT. A number of significant changes have been made, which will be reflected in the updated Guideline. These include: emphasis on repeating intramuscular adrenaline doses after 5 min if symptoms of anaphylaxis do not resolve; corticosteroids (e.g. hydrocortisone) no longer being routinely recommended for the emergency treatment of anaphylaxis; interventions for reactions which are refractory to initial treatment with adrenaline; a recommendation against the use of antihistamines for the acute management of anaphylaxis; and guidance relating to the duration of observation following anaphylaxis, and timing of discharge.