Risk factors for severe anaphylaxis in patients receiving anaphylaxis treatment in US emergency departments and hospitals

Incidence of and risk factors for paediatric perioperative anaphylaxis in the USA

BACKGROUND

Perioperative anaphylaxis is a serious and often life-threatening immediate hypersensitivity reaction. There are few published data on paediatric perioperative anaphylaxis (pPOA). We evaluated the incidence of and risk factors involved in the occurrence of pPOA within a large US national database.

METHODS

Deidentified data from the US Nationwide Inpatient Sample from 2005 to 2014 were used to identify pPOA cases and to conduct a retrospective multivariate analysis of preselected independent variables.

RESULTS

Among 3,601,180 surgeries and procedures in children aged 0-18 yr, 297 pPOA cases were identified for an incidence of one in 12,125 surgeries and procedures. Compared with controls, pPOA cases had an increased median length of stay (6 vs 2 days; P<0.001) and median hospital cost ($54 719 vs $5109; P<0.0001). The age groups between 6 and 12 yr (odds ratio [OR] 7.1; 95% confidence interval [CI] 3.9-12.9; P<0.001) and 13 and 17 yr (OR 8.5; 95% CI 4.7-15.2; P<0.001) were associated with increased odds of pPOA. Transplant (OR 46.3; 95% CI 20.8-102.9; P<0.001), cardiac (OR 16.4; 95% CI 7.5-35.9; P<0.001), and vascular (OR 15.2; 95% CI 7.5-30.7; P<0.001) procedures posed the highest risk for pPOA. Chronic pulmonary disease, coagulopathy, and fluid and electrolyte disorders were also associated with pPOA (OR 2.2; 95% CI 1.5-3.3; P<0.001).

CONCLUSIONS

The incidence of pPOA was one in 12,125 cases. Risk factors included age, procedure type, and comorbidities.

Disseminated Intravascular Coagulation in Anaphylaxis

Anaphylaxis is a life-threatening condition that involves severe cutaneous, respiratory, and cardiovascular symptoms. Disseminated intravascular coagulation (DIC) is an acquired, widespread activation of coagulation that can be caused by infectious conditions (e.g., sepsis) and noninfectious conditions. The onset of DIC following anaphylaxis is not commonly known, and information regarding the pathomechanism linking anaphylaxis to DIC is scarce. Further, demographic and clinical data in anaphylaxis-induced DIC are still missing to this day. Triggered by a case of anaphylaxis-induced DIC that seamlessly transitioned to lethal sepsis-induced DIC, we aimed to characterize the patient population affected by anaphylaxis-induced DIC by performing a review of existing literature and expand the discussion to underlying mechanisms. The overall mortality of the patient cohort (n = 30) identified by the literature review was 50%. All patients that died either suffered a bleeding event or a thrombotic event. The majority of patients (n = 25/30; 83%) had bleeding events; thrombotic events were only reported in nonsurvivors (n = 9/15 or 60% of nonsurvivors; vs. n = 0/15 in survivors; p < 0.001). Nonsurvivors of anaphylaxis-induced DIC were on average 25 years older than survivors (p = 0.068). In conclusion, DIC can complicate anaphylaxis and is expected to contribute to poor microvascular perfusion after anaphylaxis. Particularly, elderly patients with known cardiovascular disease and patients who develop thrombotic events are susceptible to lethal outcomes. As a rare and largely uncharacterized disease entity, further research is needed to investigate the link between DIC and anaphylaxis and to potentially identify better treatment strategies.

Polymorphisms of HLA genes and hypersensitivity to penicillin among patients in a Taiwanese population

Penicillin allergy is a potentially life-threatening condition that is common among patients. However, the genetic associations with penicillin allergy are not yet recognized for prevention or diagnosis, particularly in East Asian populations. We conducted a retrospective case-control study using data from the Taiwan Precision Medicine Initiative and analysing DNA samples to identify eight major MHC Class I and Class II loci. We employed imputation methods for accurate HLA typing and enrolled 17,827 individuals who received penicillin. Logistic regression analyses were utilized to explore associations between HLA genotypes, comorbidities and allergy risk, while simultaneously conducting a subgroup analysis to explore the association between HLA genotypes, comorbidities and the severity of allergic reactions. Our study assigned 496 cases to the penicillin allergy group and 4960 controls to a matched group. The risk of penicillin allergy was significantly higher with HLA-DPB1*05:01 (OR = 1.36, p = .004) and HLA-DQB1*05:01 (OR = 1.54, p = .03), with adjusted p-values of .032 and .24, respectively. Urticaria was identified as a separate risk factor (OR = 1.73, p < .001). However, neither the HLA alleles nor the comorbidities had a significant relationship with the risk of severe penicillin-induced allergy. HLA-DPB1*05:01 was found to be significantly associated with penicillin allergy reactions among the Taiwanese population.

Food Allergy Reaction Severity and Management in a Diverse Population

BACKGROUND

Definitive treatment for food allergy reactions including anaphylaxis varies widely by reaction severity and socioeconomic status, but little data exist to characterize the relationship between severity, management, and race and ethnicity.

OBJECTIVE

To analyze the differences in reaction severity, epinephrine use, and emergency room (ER) use by race and ethnicity in a large, diverse, food-allergic cohort.

METHODS

We analyzed intake data from participants in the Food Allergy Outcomes Related to White and African-American Racial Differences cohort on the history of food allergy reactions, severity of the reactions, and management associated with each reaction. We used descriptive statistics as well as mixed-effects logistic and Poisson models to describe the differences in reaction severity, ER visits, and total lifetime epinephrine use by race and ethnicity.

RESULTS

A total of 784 children were included in the analysis: 425 (54.2%) were non-Hispanic White, 282 (36.0%) were non-Hispanic Black, and 77 (9.8%) were Hispanic/Latino. Non-Hispanic Black children had increased odds of more severe reactions (odds ratio, 1.7; 95% CI, 1.2-2.3) and higher odds of going to the ER (odds ratio, 2.8; 95% CI, 1.4-5.4). Both non-Hispanic Black (incidence rate ratio, 0.4; 95% CI, 0.3-0.5) and Hispanic/Latino (incidence rate ratio, 0.3; 95% CI, 0.2-0.5) children had lower rates of total lifetime epinephrine use.

CONCLUSIONS

There are significant disparities in the severity and treatment of food allergy reactions by race and ethnicity, resulting in increased ER use and decreased total lifetime epinephrine use. Equipping parents with resources and tools on management of food allergy reactions may result in decreased disparity in access to definitive care.

Anaphylaxis: A 2023 practice parameter update

This practice parameter update focuses on 7 areas in which there are new evidence and new recommendations. Diagnostic criteria for anaphylaxis have been revised, and patterns of anaphylaxis are defined. Measurement of serum tryptase is important for diagnosis of anaphylaxis and to identify underlying mast cell disorders. In infants and toddlers, age-specific symptoms may differ from older children and adults, patient age is not correlated with reaction severity, and anaphylaxis is unlikely to be the initial reaction to an allergen on first exposure. Different community settings for anaphylaxis require specific measures for prevention and treatment of anaphylaxis. Optimal prescribing and use of epinephrine autoinjector devices require specific counseling and training of patients and caregivers, including when and how to administer the epinephrine autoinjector and whether and when to call 911. If epinephrine is used promptly, immediate activation of emergency medical services may not be required if the patient experiences a prompt, complete, and durable response. For most medical indications, the risk of stopping or changing beta-blocker or angiotensin-converting enzyme inhibitor medication may exceed the risk of more severe anaphylaxis if the medication is continued, especially in patients with insect sting anaphylaxis. Evaluation for mastocytosis, including a bone marrow biopsy, should be considered for adult patients with severe insect sting anaphylaxis or recurrent idiopathic anaphylaxis. After perioperative anaphylaxis, repeat anesthesia may proceed in the context of shared decision-making and based on the history and results of diagnostic evaluation with skin tests or in vitro tests when available, and supervised challenge when necessary.

Drug Allergy in Women

Across all settings, women self-report more drug allergies than do men. Although there is epidemiologic evidence of increased drug allergy labeling in postpubertal females, the evidence base for female sex as a risk factor for true immune-mediated drug hypersensitivity reactions (DHRs), particularly in fatal drug-induced anaphylaxis, is low. A focus on the known immunologic mechanisms described in immediate and delayed DHR, layered on known hormonal and genetic sex differences that drive other immune-mediated diseases, could be the key to understanding biological sex variations in DHR. Particular conditions that highlight the impact of drug allergy in women include (1) pregnancy, in which a drug allergy label is associated with increased maternal and fetal complications; (2) multiple drug intolerance syndrome, associated with anxiety and depression; and (3) female-predominant autoimmune medical conditions in the context of mislabeling of the drug allergy or increased underlying risk. In this review, we describe the importance of drug allergy in the female population, mainly focusing on the epidemiology and risk, the mechanisms, and the associated conditions and psychosocial factors. By performing a detailed analysis of the current literature, we provide focused conclusions and identify existing knowledge gaps that should be prioritized for future research.

Trends and Hospital Outcomes in HOSPITAL Admissions for Anaphylaxis in Children with and without Asthma in Spain (2016-2021)

(1) Background: To assess and compare the temporal trends in the incidence, characteristics and hospital outcomes among children with and without asthma who were hospitalized with anaphylaxis in Spain from 2016 to 2021, and identify the variables associated with severe anaphylaxis among children with asthma. (2) Methods: An observational, retrospective study was conducted using a population-based database. The study population included pediatric patients with anaphylaxis. This population was stratified based on whether they had asthma. (3) Results: The number of hospital admissions was stable from 2016 to 2019, dropping in 2020 and raising to the highest number in 2021. A total of 60.63% of hospitalizations occurred in boys and the most common anaphylactic reactions were due to food consumption (67.28%), increasing over time. The in-hospital mortality (IHM) remained stable and under 1% in all the years studied. The incidence of anaphylaxis was 2.14 times higher in children with asthma than in those without asthma (IRR 2.14; 95% CI 1.87-2.44). Furthermore, it was 1.79 times higher in boys with asthma than in those without asthma (IRR 1.79; 95% CI 1.06-2.45) and 2.68 times higher in girls with asthma than in those without asthma (IRR 2.68; 95% CI 2.23-3.12). Asthma was not associated with severe anaphylaxis (OR 1.31; 95% CI 0.88-1.96). (4) Conclusions: The number of hospitalizations for anaphylaxis in children remained stable from 2016 to 2019, dropping in 2020 and recovering in 2021. IHM was low and remained stable during the study period. The incidence of hospitalizations for anaphylaxis was higher in asthmatic children than in non-asthmatics, but there were no differences in the occurrence of severe anaphylaxis among them.

Analysis of drug-induced anaphylaxis cases using the Japanese Adverse Drug Event Report (JADER) database - secondary publication

BACKGROUND

The epidemiology of drug-induced anaphylaxis using the Japanese nationwide database has been not reported, even though drugs are a common trigger of anaphylaxis. The aim of this study was to describe the epidemiological profile of cases of drug-induced anaphylaxis, including fatal cases, using the data from the Japanese Adverse Drug Event Report database (JADER).

METHODS

We extracted data regarding drug-related adverse events, between April 2004 and February 2018, published in JADER by the Pharmaceuticals and Medical Devices Agency. We analyzed cases of anaphylaxis occurring between January 2005 and December 2017. The drug classification was based on the Japanese Standard Commodity Classification.

RESULTS

There were 16,916 cases of anaphylaxis reported during the study period. Among them, 418 fatalities were registered. The incidence of drug-induced anaphylaxis and fatal cases was 1.03 cases/year per 100,000 population and 0.03 cases/year, respectively. The most frequent causes of anaphylaxis were diagnostic agents, including X-ray contrast media (20.3%), and biological preparations, such as human blood preparations (20.1%). In fatal cases, diagnostic agents (28.7%) and antibiotic preparations (23.9%) were the most commonly associated types of drugs.

CONCLUSIONS

The frequency of drug-induced anaphylaxis and fatalities in Japan remained unchanged over the 13-year period analyzed in this study. Diagnostic agents and biological preparations were the most frequent causes of anaphylaxis; however, fatalities were most frequently caused by either diagnostic agents or antibiotic preparations.

Refractory cardiac arrest caused by type I Kounis syndrome treated with adrenaline and nicorandil: A case report

RATIONALE

Kounis syndrome is a rare but life-threatening anaphylactic reaction that can lead to acute coronary syndrome and cardiac arrest, and requires prompt diagnosis. Adrenaline, which is used to treat anaphylaxis, may cause coronary vasoconstriction and worsen ischemia, whereas coronary vasodilators may dilate systemic vessels and exacerbate hypotension. Delayed diagnosis of Kounis syndrome and inadequate therapeutic intervention may thus lead to a poor outcome.

PATIENT CONCERNS

A 59-year-old man was treated for sepsis due to a liver abscess. Following administration of daptomycin, the patient developed severe anaphylactic shock leading to refractory cardiac arrest. Because conventional cardiopulmonary resuscitation was ineffective, extracorporeal cardiopulmonary resuscitation was considered as an alternative approach.

DIAGNOSES

On bedside monitoring during cardiopulmonary resuscitation, unexpected ST-segment elevation was found on lead II electrocardiogram. Accordingly, the patient was clinically diagnosed with Kounis syndrome.

INTERVENTIONS

Nicorandil (6 mg/h), a coronary vasodilator with minimal blood pressure effects, was administered along with high doses of vasopressors, including adrenaline 0.2 µg/kg/min.

OUTCOMES

After the initiation of nicorandil administration, the patient achieved return of spontaneous circulation and did not require extracorporeal cardiopulmonary resuscitation. Based on the elevated serum tryptase level, normal creatine kinase-MB range, and lack of stenosis on coronary angiography, the patient was definitively diagnosed with type I (coronary vasospasm) Kounis syndrome. He was subsequently transferred to the referring hospital without neurological sequelae.

LESSONS

If anaphylaxis leads to refractory shock and cardiac arrest, ischemic changes on the electrocardiogram should be investigated to identify underlying Kounis syndrome. In addition to adrenaline, coronary dilators are the definitive treatment. Nicorandil may be a useful treatment option because of its minimal effect on blood pressure.

Drug Hypersensitivity Reactions

Drug hypersensitivity reactions are a diverse group of reactions mediated by the immune system after exposure to a drug. The Gell and Coombs classification divides immunologic DHRs into 4 major pathophysiologic categories based on immunologic mechanism. Anaphylaxis is a Type I hypersensitivity reaction that requires immediate recognition and treatment. Severe cutaneous adverse reactions (SCARs) are a group of dermatologic diseases that result from a Type IV hypersensitivity process and include drug reaction with eosinophilia and systemic symptom (DRESS) syndrome, Stevens-Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN), and acute generalized exanthematous pustulosis (AGEP). Other types of reactions are slow to develop and do not always require rapid treatment. Emergency physicians should have a good understanding of these various types of drug hypersensitivity reactions and how to approach the patient regarding evaluation and treatment.

Overview of Allergy and Anaphylaxis

Allergic reactions and anaphylaxis occur on a severity continuum from mild and self-limited to potentially life-threatening or fatal reactions. Anaphylaxis is typically a multiorgan phenomenon involving a broad range of effector cells and mediators. Emergency department visits for anaphylaxis are increasing, especially among children. There is a broad differential diagnosis for anaphylaxis, and the diagnosis of anaphylaxis can be aided by the use of the National Institutes of Allergy and Infectious Disease/Food Allergy and Anaphylaxis Network clinical diagnostic criteria. Risk factors for severe anaphylaxis include older age, delayed epinephrine administration, and cardiopulmonary comorbidities.

Identifying and Managing Those at Risk for Vaccine-Related Allergy and Anaphylaxis

Immediate hypersensitivity reactions to vaccines, the most severe of which is anaphylaxis, are uncommon events occurring in fewer than 1 in a million doses administered. These reactions are infrequently immunoglobulin E-mediated. Because they are unlikely to recur, a reaction to a single dose of a vaccine is rarely a contraindication to redosing. This narrative review article contextualizes the recent knowledge we have gained from the coronavirus 2019 (COVID-19) pandemic rollout of the new mRNA platform with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines within the much broader context of what is known about immediate reactions to other vaccinations of routine and global importance. We focus on what is known about evidence-based approaches to diagnosis and management and what is new in our understanding of mechanisms of immediate vaccine reactions. Specifically, we review the epidemiology of immediate hypersensitivity vaccine reactions, differential diagnosis for immune-mediated and nonimmune reaction clinical phenotypes, including how to recognize immunization stress-related responses. In addition, we highlight what is known about mechanisms and review the rare but important contribution of excipient allergies and specifically when to consider testing for them as well as other key features that contribute to safe evaluation and management.

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.

International consensus statement on allergy and rhinology: Allergic rhinitis - 2023

BACKGROUND

In the 5 years that have passed since the publication of the 2018 International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis (ICAR-Allergic Rhinitis 2018), the literature has expanded substantially. The ICAR-Allergic Rhinitis 2023 update presents 144 individual topics on allergic rhinitis (AR), expanded by over 40 topics from the 2018 document. Originally presented topics from 2018 have also been reviewed and updated. The executive summary highlights key evidence-based findings and recommendation from the full document.

METHODS

ICAR-Allergic Rhinitis 2023 employed established evidence-based review with recommendation (EBRR) methodology to individually evaluate each topic. Stepwise iterative peer review and consensus was performed for each topic. The final document was then collated and includes the results of this work.

RESULTS

ICAR-Allergic Rhinitis 2023 includes 10 major content areas and 144 individual topics related to AR. For a substantial proportion of topics included, an aggregate grade of evidence is presented, which is determined by collating the levels of evidence for each available study identified in the literature. For topics in which a diagnostic or therapeutic intervention is considered, a recommendation summary is presented, which considers the aggregate grade of evidence, benefit, harm, and cost.

CONCLUSION

The ICAR-Allergic Rhinitis 2023 update provides a comprehensive evaluation of AR and the currently available evidence. It is this evidence that contributes to our current knowledge base and recommendations for patient evaluation and treatment.

Idiopathic Anaphylaxis? Analysis of Data from the Anaphylaxis Registry for West Pomerania Province, Poland

The most common causes of anaphylaxis, according to various authors and depending on the age of the studied groups, are: Hymenoptera venom, food, and medications. Unfortunately, we are not always able to indicate the cause of anaphylaxis. There are data in the literature where as many as 41% of all cases are idiopathic anaphylaxis. Since the introduction of new diagnostic methods such as molecular diagnostics (MD) in our centre, the percentage of idiopathic anaphylaxis in the Anaphylaxis Register has significantly decreased. The purpose of this study was to identify possible causes of idiopathic anaphylaxis in patients with a history of moderate to severe anaphylactic reactions. After using MD, the causative agent was found in another 29 people. The proportion of people with idiopathic anaphylaxis in the Registry decreased from 9.2% to 3.5%. There were no significant differences in the incidence, although men appear to be slightly more common in primary idiopathic anaphylaxis. The mean age of primary idiopathic anaphylaxis was 40 years, but this was as high as 51 for anaphylaxis with alpha-gal allergy. Exercise may or may not be present as a cofactor despite its established role, e.g., in wheat-dependent exercise-induced anaphylaxis (WDEIA). In most of the analyzed cases, i.e., 70%, the reaction took place within an hour. The longest time interval from exposure to the development of symptoms is in the case of alpha-gal allergy; in this analysis, it was at least 5 h after ingestion of the so-called "red meat". Patients are not aware of the disease, or further attacks cannot be prevented. As many as 80% had idiopathic anaphylaxis prior to visiting the centre, and 80% developed anaphylaxis after visiting the centre, which emphasizes the need to not stop the medical team in their search for the causes. As many as 93% of cases required medical intervention, of which adrenaline was used only in 34.5%, antihistamines in 86%, systemic glucocorticosteroids (sCS) in 75%, and fluids in 62% of cases. A total of 83% of patients received an emergency kit for self-administration. Idiopathic anaphylaxis can be resolved as known-cause anaphylaxis after a thorough medical history and, if possible, without exposing the patient after using appropriate, modern in vitro diagnostic methods, including molecular diagnostics. The diagnosis of idiopathic anaphylaxis should extend the diagnosis to include alpha-gal syndrome, LTP syndrome and WDEIA.

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.

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.

Cardiac arrest caused by anaphylaxis refractory to prompt management: A case series and review of the literature

BACKGROUND

Anaphylaxis is a potentially life-threatening condition that occurs in the emergency department (ED). Although anaphylaxis is rapidly recognized and treated in the hospital compared with that in the community, in some cases, it does not respond to proper management.

OBJECTIVE

The aim of this study is to describe our experience of cases of refractory anaphylaxis leading to cardiac arrest in hospital, to review their characteristics compared with those seen in the community, and to discuss the best management practices for anaphylaxis-induced cardiac arrest with a literature review.

METHODS

We reviewed the medical records of patients referred to the ED with possible in-hospital anaphylaxis between January 2017 and May 2021. According to the anaphylaxis protocol, epinephrine, corticosteroid, and antihistamine were administered immediately on-site at our institution before the study period. Refractory anaphylaxis was defined as the development of anaphylaxis-induced cardiac arrest even after following the anaphylaxis protocol.

RESULTS

A total of 246 cases were evaluated for possible anaphylaxis, with 236 cases meeting the criteria for a diagnosis of anaphylaxis. Among them, 178 patients showed the signs and symptoms of shock, and cardiac arrest occurred in 6 patients (2.5%). Of the six patients, three had a return of spontaneous circulation before admission to the ED, while two died due to refractory cardiac arrest despite resuscitation in the ED. Following post-cardiac arrest care, including temperature management, one patient who received extracorporeal cardiopulmonary resuscitation survived neurologically intact.

CONCLUSION

We present our case series to highlight the risk of developing refractory anaphylaxis with subsequent in-hospital cardiac arrest. Patients may progress to cardiac arrest within minutes despite prompt recognition and management. If patients present with potentially fatal symptoms, a more aggressive approach, including intravenous adrenaline infusion, should be taken.

Anaphylaxis among elderly emergency department patients in a large health system in New York

BACKGROUND

Anaphylaxis in the elderly is poorly understood.

OBJECTIVE

To elucidate demographic, clinical, and management characteristics of older adults presenting to emergency departments (EDs) with National Institute of Allergy and Infectious Diseases (NIAID) criteria-confirmed anaphylaxis vs milder, non-anaphylactic acute allergic reactions (AARs).

METHODS

A retrospective analysis of ED patients more than or equal to 65 years was conducted, using anaphylaxis International Classification of Diseases, Ninth Revision (ICD-9) codes or ICD-9-based algorithms incorporating the NIAID diagnostic criteria. Descriptive statistics were generated, and the abovementioned characteristics were compared between cohorts.

RESULTS

Of 164 eligible visits, 71 (43.3%), 90 (54.9%), and 3 (1.8%) cases were identified by ICD-9 codes, the algorithms, or both, respectively. Only half fulfilled NIAID diagnostic criteria. Compared with the non-anaphylactic AAR group, criteria-confirmed anaphylaxis group had lower drug allergy rates (43.9% vs 61.0%, P = .03) but higher food allergy rates (26.8% vs 12.2%, P = .02). For the criteria-confirmed anaphylaxis group, presenting signs and symptoms in descending frequency were mucocutaneous, respiratory, cardiovascular, and gastrointestinal. Criteria-confirmed anaphylaxis group had higher rates of prior anaphylaxis (13.4% vs 2.4%, P = .009), pre-ED (12.2% vs 0.0%, P = .001) or ED (72.0% vs 4.9%, P < .001) epinephrine administration, and allergy referral (17.1% vs 2.4%, P = .002). Tryptase levels were rarely ordered, occurring once in the criteria-confirmed anaphylaxis group and never in the non-anaphylactic AAR group. Despite low mortality (n = 1), 64.6% of the criteria-confirmed anaphylaxis cohort required hospitalization, with 23.2% admitted to intensive care unit.

CONCLUSION

Diagnosis of elderly ED patients with anaphylaxis remains suboptimal. Identifying NIAID criteria-confirmed cases remain challenging, using the existing methods. Management of these patients poorly adheres to current guidelines.

Tree Nut-Induced Anaphylaxis in Canadian Emergency Departments: Rate, Clinical Characteristics and Management

BACKGROUND

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

OBJECTIVE

We aimed to characterize rate, clinical characteristics, and management of TNA in children (0-17 years old) across Canada, and assess factors associated with severe reactions and epinephrine use.

METHODS

Between April 2011 and May 2020, data were collected on children presenting to five emergency departments (EDs) 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 years [Interquartile range (IQR): 2.5-9.5] and 65.4% were males. 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% CI, 1.6%-27.6%)] versus Ontario and Quebec, whereas pistachio-induced anaphylaxis was more common in Ontario and Quebec [6.3% difference (95% CI, 0.5%-12.2%)]. Pre-hospital and ED intramuscular (IM) epinephrine administration was documented in only 35.2% and 52.4% of cases, respectively. Severe reactions were more likely among males [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 due to differences in lifestyle (higher prevalence of Asian ethnicity in British Columbia versus Arabic ethnicity in Ontario and Quebec). IM epinephrine underutilization urges for EAI stocking in schools and restaurants, patient education, and consistent policies across Canada.

Allergic reactions to COVID-19 vaccines: statement of the Belgian Society for Allergy and Clinical Immunology (BelSACI)

Vaccination against COVID-19 constitutes a huge hope and a major challenge. For the first time in modern history, a global vaccination campaign has started worldwide in a short period of time and with products that were recently developed. Consequently, legitimate concerns regarding the safety and tolerability of COVID-19 vaccines arise.In line with international allergy societies, the Belgian Society for Allergy and Clinical Immunology (BelSACI) provides this statement to guide health care providers (general practitioners, specialists including allergists) and stakeholders.In this statement, we first review current evidence on allergic reactions to vaccines and the potential risk factors that have been identified.Second, we provide a risk stratification method that may be used as a worksheet during the vaccination campaign.Finally, we discuss the management of suspected or confirmed allergic reactions following vaccination.

Drug-Related Hypersensitivity Reactions Leading to Emergency Department: Original Data and Systematic Review

The aim of the present study is to describe pharmacological characteristics of drug-related allergies and anaphylaxis leading to the emergency department (ED). An 8-year post hoc analysis on the MEREAFaPS Study database was performed (2012−2019). Subjects who experienced drug-related hypersensitivity leading to an ED visit were selected. Logistic regression analyses were used to estimate the reporting odds ratios (RORs) of drug-related allergies and anaphylaxis adjusting for sex, age classes, and ethnicity. In addition, a systematic review of observational studies evaluating drug-related hypersensitivity reactions leading to ED visits in outpatients was performed. Out of 94,073 ED visits, 14.4% cases were drug-related allergies and 0.6% were anaphylaxis. Females accounted for 56%. Multivariate logistic regression showed a higher risk of drug-related allergy among males and all age classes < 65 years, while a higher risk of anaphylaxis was observed for females (ROR 1.20 [1.01−1.42]) and adults (ROR 2.63 [2.21−3.14]). The systematic review included 37 studies. ED visits related to allergy and anaphylaxis ranged from 0.004% to 88%, and drug-related allergies and anaphylaxis ranged from 0.007% to 88%. Both in our analysis and in primary studies, antibacterials, analgesics, and radiocontrast agents were identified as the most common triggers of hypersensitivity.

Changing pattern of pediatric anaphylaxis in Hong Kong, 2010-2019

BACKGROUND

Anaphylaxis is a significant health burden in most Western countries, but there are little published data on the incidence and pattern of anaphylaxis in Asia. We aim to determine the incidence rate and pattern of anaphylaxis over the past decade among the pediatric population in Hong Kong.

METHODS

Medical records of patients presenting with allergy-related symptoms during the period 2010 to 2019 were examined. Pediatric patients aged below 18 years who fulfilled the diagnostic criteria for anaphylaxis laid out by the NIAID/FAAN were analyzed. Incidence rates were calculated using population statistics as the denominator. All information pertaining to the anaphylaxis events and patients' characteristics was retrieved using standardized data collection forms.

RESULTS

The overall 10-year estimated incidence of anaphylaxis was 9.76 per 100,000 person-years, with a rising trend of anaphylaxis incidence across time. Food-induced anaphylaxis accounted for the majority of hospital presentations, of which peanut and shellfish were the top food triggers in our population. Majority of anaphylaxis episodes were of Grade 4 severity, and young age was a significant predictor of severe allergic reactions. Half of the anaphylaxis episodes were misdiagnosed and adrenaline was only utilized in 42.2% of cases, of which 9.4% were administered adrenaline prior to hospital arrival.

CONCLUSIONS

An increasing trend of anaphylaxis incidence over the past decade is evident in Hong Kong children, with a discrepantly low accuracy in diagnosis and suboptimal management of anaphylaxis. There is a pressing need to heighten public and physicians' awareness of the distinctive features of anaphylaxis in the pediatric age-group.

Anaphylaxis to Drugs, Biological Agents, and Vaccines

Anaphylaxis is a multi-system syndrome resulting from the release of mediators from mast cells and basophils. Drugs are common causes. Anaphylaxis to certain drugs, vaccines, and biological agents present clinical challenges, and merit referral to a board-certified allergist/immunologist for further evaluation and management.

Overview of Allergy and Anaphylaxis

Allergic reactions and anaphylaxis occur on a severity continuum from mild and self-limited to potentially life-threatening or fatal reactions. Anaphylaxis is typically a multiorgan phenomenon involving a broad range of effector cells and mediators. Emergency department visits for anaphylaxis are increasing, especially among children. There is a broad differential diagnosis for anaphylaxis, and the diagnosis of anaphylaxis can be aided by the use of the National Institutes of Allergy and Infectious Disease/Food Allergy and Anaphylaxis Network clinical diagnostic criteria. Risk factors for severe anaphylaxis include older age, delayed epinephrine administration, and cardiopulmonary comorbidities.

Drug Hypersensitivity Reactions

Drug hypersensitivity reactions are a diverse group of reactions mediated by the immune system after exposure to a drug. The Gell and Coombs classification divides immunologic DHRs into 4 major pathophysiologic categories based on immunologic mechanism. Anaphylaxis is a Type I hypersensitivity reaction that requires immediate recognition and treatment. Severe cutaneous adverse reactions (SCARs) are a group of dermatologic diseases that result from a Type IV hypersensitivity process and include drug reaction with eosinophilia and systemic symptom (DRESS) syndrome, Stevens-Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN), and acute generalized exanthematous pustulosis (AGEP). Other types of reactions are slow to develop and do not always require rapid treatment. Emergency physicians should have a good understanding of these various types of drug hypersensitivity reactions and how to approach the patient regarding evaluation and treatment.

Association of Self-reported High-Risk Allergy History With Allergy Symptoms After COVID-19 Vaccination

IMPORTANCE

Allergic history in individuals with confirmed anaphylaxis to a messenger RNA (mRNA) COVID-19 vaccine is common. However, the risk factors for allergy symptoms after receiving the vaccine are unknown.

OBJECTIVE

To assess the association between self-reported history of high-risk allergy and self-reported allergic reactions after mRNA COVID-19 vaccination of health care employees.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study obtained demographic, medical, and vaccine administration data of employees of Mass General Brigham from the institutional electronic health record. Employees who received at least 1 dose of an mRNA COVID-19 vaccine between December 14, 2020, and February 1, 2021, and who completed at least 1 postvaccination symptom survey in the 3 days after vaccination were included.

EXPOSURES

Self-reported history of high-risk allergy, defined as a previous severe allergic reaction to a vaccine, an injectable medication, or other allergen.

MAIN OUTCOMES AND MEASURES

The primary outcome was 1 or more self-reported allergic reactions in the first 3 days after dose 1 or dose 2 of an mRNA COVID-19 vaccine. Multivariable log binomial regression was used to assess the association between allergic reactions and high-risk allergy status.

RESULTS

A total of 52 998 health care employees (mean [SD] age, 42 [14] years; 38 167 women [72.0%]) were included in the cohort, of whom 51 706 (97.6%) received 2 doses of an mRNA COVID-19 vaccine and 474 (0.9%) reported a history of high-risk allergy. Individuals with vs without a history of high-risk allergy reported more allergic reactions after receiving dose 1 or 2 of the vaccine (11.6% [n = 55] vs 4.7% [n = 2461]). In the adjusted model, a history of high-risk allergy was associated with an increased risk of allergic reactions (adjusted relative risk [aRR], 2.46; 95% CI, 1.92-3.16), with risk being highest for hives (aRR, 3.81; 95% CI, 2.33-6.22) and angioedema (aRR, 4.36; 95% CI, 2.52-7.54).

CONCLUSIONS AND RELEVANCE

This cohort study found that self-reported history of high-risk allergy was associated with an increased risk of self-reported allergic reactions within 3 days of mRNA COVID-19 vaccination. However, reported allergy symptoms did not impede the completion of the 2-dose vaccine protocol among a cohort of eligible health care employees, supporting the overall safety of mRNA COVID-19 vaccine.

Risk factors of beta-lactam anaphylaxis in Korea: A 6-year multicenter retrospective adult case-control study

Background

Beta-lactams (BLs) are commonly used antibiotics and leading causative agents of drug-induced anaphylaxis. Few studies on the culprit drugs and risk factors of BL-induced anaphylaxis are available. Our goal was to evaluate the culprit drugs and compare the risk factors in patients with BL-induced anaphylaxis to matched tolerant controls in a hospital setting.

Methods

We retrospectively enrolled all patients who developed anaphylaxis from intravenous BL during hospitalization from 9 Korean hospitals. We compared clinical parameters between patients with BL-induced anaphylaxis and 4-fold BL-tolerant controls matched by age, sex, BL use, and the purpose of BL administration.

Results

Seventy-four cases of BL-induced anaphylaxis and 296 BL-tolerant controls were enrolled. Cephalosporin accounted for 77% of total BL-induced anaphylaxis, and the top derivatives were ceftriaxone (23.0%), cefazedone (10.8%), and cefbuperazone (9.5%). Among penicillin derivatives, piperacillin (16.2%) was the most common, followed by ampicillin (2.7%). History of drug allergy (odds ratio [OR], 19.91; 95% confidence interval [CI] 5.33–74.44), previous exposure to the causative BL (OR, 7.71; 95% CI, 1.62–36.76), and concurrent administration of angiotensin-converting enzyme inhibitors (ACEIs) (OR, 5.97; 95% CI, 1.28–27.91) were independent risk factors associated with BL-induced anaphylaxis. Food allergy (OR, 13.93; 95% CI 1.31–148.9) and previous exposure to BL (OR, 6.59; 95% CI, 1.30–33.31) were identified as risk factors for cephalosporin-induced anaphylaxis.

Conclusions

To prevent BL-induced anaphylaxis, attention should be paid to histories of drug or food allergy, previous exposure to BLs, and ACEI use. The risk factors and clinical outcomes might vary according to the BL classes.

Assessment of Allergic and Anaphylactic Reactions to mRNA COVID-19 Vaccines With Confirmatory Testing in a US Regional Health System

IMPORTANCE

As of May 2021, more than 32 million cases of COVID-19 have been confirmed in the United States, resulting in more than 615 000 deaths. Anaphylactic reactions associated with the Food and Drug Administration (FDA)-authorized mRNA COVID-19 vaccines have been reported.

OBJECTIVE

To characterize the immunologic mechanisms underlying allergic reactions to these vaccines.

DESIGN, SETTING, AND PARTICIPANTS

This case series included 22 patients with suspected allergic reactions to mRNA COVID-19 vaccines between December 18, 2020, and January 27, 2021, at a large regional health care network. Participants were individuals who received at least 1 of the following International Statistical Classification of Diseases and Related Health Problems, Tenth Revision anaphylaxis codes: T78.2XXA, T80.52XA, T78.2XXD, or E949.9, with documentation of COVID-19 vaccination. Suspected allergy cases were identified and invited for follow-up allergy testing.

EXPOSURES

FDA-authorized mRNA COVID-19 vaccines.

MAIN OUTCOMES AND MEASURES

Allergic reactions were graded using standard definitions, including Brighton criteria. Skin prick testing was conducted to polyethylene glycol (PEG) and polysorbate 80 (P80). Histamine (1 mg/mL) and filtered saline (negative control) were used for internal validation. Basophil activation testing after stimulation for 30 minutes at 37 °C was also conducted. Concentrations of immunoglobulin (Ig) G and IgE antibodies to PEG were obtained to determine possible mechanisms.

RESULTS

Of 22 patients (20 [91%] women; mean [SD] age, 40.9 [10.3] years; 15 [68%] with clinical allergy history), 17 (77%) met Brighton anaphylaxis criteria. All reactions fully resolved. Of patients who underwent skin prick tests, 0 of 11 tested positive to PEG, 0 of 11 tested positive to P80, and 1 of 10 (10%) tested positive to the same brand of mRNA vaccine used to vaccinate that individual. Among these same participants, 10 of 11 (91%) had positive basophil activation test results to PEG and 11 of 11 (100%) had positive basophil activation test results to their administered mRNA vaccine. No PEG IgE was detected; instead, PEG IgG was found in tested individuals who had an allergy to the vaccine.

CONCLUSIONS AND RELEVANCE

Based on this case series, women and those with a history of allergic reactions appear at have an elevated risk of mRNA vaccine allergy. Immunological testing suggests non-IgE-mediated immune responses to PEG may be responsible in most individuals.

Validity of hospital ICD-10-GM codes to identify anaphylaxis

PURPOSE

Anaphylaxis (ANA) is an important adverse drug reaction. We examined positive predictive values (PPV) and other test characteristics of ICD-10-GM code algorithms for detecting ANA as used in a multinational safety study (PASS).

METHODS

We performed a cross-sectional study on routine data from a German academic hospital (2004-2019, age ≥ 18). Chart review was used for case verification. Potential cases were identified from the hospital administration system. The main outcome required at least one of the following: any type of specific in-hospital code (T78.2, T88.6, and T80.5) OR specific outpatient code in combination with a symptom code OR in-hospital non-specific code (T78.4, T88.7, and Y57.9) in combination with two symptom codes. PPV were calculated with 95% confidence interval. Sensitivity analyses modified type of codes, unit of analysis, verification criteria and time period. The most specific algorithm used only primary codes for ANA (numbers added in brackets).

RESULTS

Four hundred and sixteen eligible cases were evaluated, and 78 (37) potential ANA cases were identified. PPV were 62.8% (95% CI 51.1-73.5) (main) and 77.4% (58.9-90.4) (most specific). PPV from all modifications ranged from 12.9% to 80.6%. The sensitivity of the main algorithm was 66.2%, specificity 91.5%, and negative predictive value 92.6%. Corresponding figures for the most specific algorithm were 32.4%, 98.0%, and 87.0%.

CONCLUSIONS

The PPV of the main algorithm seems of acceptable validity for use in comparative safety research but will underestimate absolute risks by about a third. Restriction to primary discharge codes markedly improves PPV to the expense of reducing sensitivity.

Vaccines and allergic reactions: The past, the current COVID-19 pandemic, and future perspectives

Vaccines are essential public health tools with a favorable safety profile and prophylactic effectiveness that have historically played significant roles in reducing infectious disease burden in populations, when the majority of individuals are vaccinated. The COVID-19 vaccines are expected to have similar positive impacts on health across the globe. While serious allergic reactions to vaccines are rare, their underlying mechanisms and implications for clinical management should be considered to provide individuals with the safest care possible. In this review, we provide an overview of different types of allergic adverse reactions that can potentially occur after vaccination and individual vaccine components capable of causing the allergic adverse reactions. We present the incidence of allergic adverse reactions during clinical studies and through post-authorization and post-marketing surveillance and provide plausible causes of these reactions based on potential allergenic components present in several common vaccines. Additionally, we review implications for individual diagnosis and management and vaccine manufacturing overall. Finally, we suggest areas for future research.

Mechanisms of human drug-induced anaphylaxis

Drug-induced anaphylaxis is a hyperacute reaction affecting multiple organs that can be of fatal consequence. Its incidence is increasing, consistent with a global increased sensitization to various allergens and drugs in the population. Few risk factors and mechanisms have been identified from human studies due to the rarity of anaphylactic events and their unpredictability. This systemic reaction is caused by the rapid release of a large range of functionally diverse mediators, including histamine and platelet-activating factor as the main drivers identified. Mechanisms defined from models of experimental anaphylaxis identify drug-specific antibodies of the IgE and IgG class that link the drug to antibody receptors on multiple cell types, causing their activation and mediator release. In the case of drugs with peculiar chemical structures, antibodies may not be necessary because drug-binding receptors, such as Mas-related G protein-coupled receptor member X2, have been identified. This review describes the complex reaction leading to drug-induced anaphylaxis that can involve various antibody classes, various cell types-including mast cells, neutrophils, platelets, basophils, macrophages, and monocytes-and their mediators and receptors that, importantly, can be activated alone or in association to participate in the severity of the reaction.

Trends in Emergency Department Visits and Hospitalizations for Acute Allergic Reactions and Anaphylaxis Among US Older Adults: 2006-2014

BACKGROUND

The US older adult population (age ≥65 years) is increasing and may be at increased risk for severe anaphylaxis. Little is known about the health care use for acute allergic reactions (AAR), including anaphylaxis, among older adults.

OBJECTIVE

To characterize trends in emergency department (ED) visits and hospitalizations for AAR and anaphylaxis among US older adults from 2006 to 2014 and examine factors associated with severe anaphylaxis.

METHODS

We performed cross-sectional analyses of trends in ED visits and hospitalizations among older adults using data from the Nationwide Emergency Department Sample and the National (Nationwide) Inpatient Sample in 2006 to 2014. We used International Classification of Diseases, Ninth Revision, Clinical Modification diagnostic codes to identify visits for AAR, including anaphylaxis. Multivariable logistic regression modeling was used to identify factors associated with severe anaphylaxis (cardiac arrest, intubation, and death).

RESULTS

In 2006 to 2014, older adults experienced approximately 1,019,967 AAR-related ED visits, 173,844 AAR-related hospitalizations, 93,795 anaphylaxis-related ED visits, and 72,677 anaphylaxis-related hospitalizations. Whereas AAR-related ED visit and hospitalization rates remained stable (P = .28 and .16, respectively), anaphylaxis-related ED visit and hospitalization rates increased significantly over time (37 visits/100,000 in 2006 to 51 in 2014, P < .001; and from 13 hospitalizations/100,000 in 2006 to 23 in 2014, P < .001), especially hospitalization rates for drug-related anaphylaxis (47 hospitalizations/100,000 in 2006 to 85 in 2014; P < .001). Risk factors for anaphylaxis-related death included older age and drug-related trigger.

CONCLUSIONS

In a nationally representative sample of US older adults, the rate of anaphylaxis-related ED visits and hospitalizations increased over time. Drug-related triggers represented a substantial portion of increased health care use and are a growing risk in this vulnerable population.

Management of Anaphylaxis During the SARS-CoV-2 Pandemic

Purpose of Review

Management of anaphylaxis during the SARS-CoV-2 pandemic should consider local infection rates so as to not burden local ED at times of pandemic, while also protecting patients from infection risks and progression of anaphylaxis. In this review, we identify a treatment strategy for anaphylaxis that balances the risks versus benefits of ED versus home management in this unprecedented time.

Recent Findings

Physicians and patients have had to adapt new approaches to medical care during the SARS-CoV-2 pandemic due to restricted access to health care facilities. Telemedicine has substituted in-person visits, and such a drastic change in the patient care paradigm presents a need to revise the acute management of anaphylaxis.

Summary

Physicians should utilize telemedicine during this time to engage in shared decision-making with patients and their families to devise an anaphylaxis plan of management that emphasizes home care when symptoms are mild with an exception for ED care if a patient has had severe, near-fatal anaphylaxis episodes in the past. Previous anaphylaxis recommendations should remain in place despite the pandemic, including prompt use of epinephrine when needed, avoidance of known allergens, training of patients and their caregivers, and carrying of epinephrine autoinjector devices at all times to remain prepared in the event of an anaphylaxis episode.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40521-021-00284-0.

A Cost-Effectiveness Evaluation of Hospitalizations, Fatalities, and Economic Outcomes Associated with Universal Versus Anaphylaxis Risk-Stratified COVID-19 Vaccination Strategies

BACKGROUND

Vaccine-associated anaphylaxis is a rare event (1.34 events/million doses; 0.00017% occurrence over 26 years). Several reports of allergic reactions concerning for anaphylaxis have been reported early into the Pfizer-BioNTech and Moderna coronavirus disease 2019 (COVID-19) vaccine campaign in the United States, Canada, and the United Kingdom.

OBJECTIVE

To perform a cost-effectiveness analysis characterizing the risks of COVID-19 versus vaccine anaphylaxis, comparing universal COVID-19 vaccination versus risk-stratified vaccination approaches.

METHODS

Cohort analysis models were created to evaluate the cost-effectiveness of universal vaccination versus risk-stratified vaccination (eg, contraindicated in persons with a history of any previous episode of anaphylaxis) with a threshold for cost-effective care at $10,000,000 per death prevented. In the base case, risk of anaphylaxis was estimated at 0.1%, with case-fatality estimated at 0.3%.

RESULTS

On a population level (n = 300,000,000 simulated persons), universal vaccination was associated with a cost-savings of $503,596,316 and saved 7,607 lives, but the cost-savings was sensitive to increasing rates of vaccine-associated anaphylaxis. The universal strategy dominated at higher rates of COVID-19 infection and low rates of vaccine-associated anaphylaxis in both the health care and societal perspectives. When the risk of vaccine-associated anaphylaxis exceeded 0.8%, the risk-stratified approach to vaccination was the most cost-effective strategy. There was also an interaction between anaphylaxis risk and anaphylaxis fatality, with a risk-stratified approach becoming cost-effective as each risk increased concurrently. Stratified observation time by anaphylaxis history (15 minutes vs 30 minutes) was not cost-effective until a 1% anaphylaxis case-fatality was assumed and risk of vaccine anaphylaxis exceeded 6%.

CONCLUSIONS

This study demonstrates that unless vaccine anaphylaxis rates exceed 0.8%, a universal vaccination approach dominates a risk-stratified approach where persons with any history of anaphylaxis would be contraindicated from vaccination, with lower cost and superior health outcomes.

Consensus on DEfinition of Food Allergy SEverity (DEFASE) an integrated mixed methods systematic review

BACKGROUND AND AIMS

The term "Food Allergy" refers to a complex global health problem with a wide spectrum of severity. However, a uniform definition of severe food allergy is currently missing. This systematic review is the preliminary step towards a state-of-the-art synopsis of the current evidence relating to the severity of IgE-mediated food allergy; it will inform attempts to develop a consensus to define food allergy severity by clinicians and other stakeholders.

METHODS

We undertook a mixed-methods systematic review, which involved searching 11 international biomedical databases for published studies from inception to 31 December 2019. Studies were independently screened against pre-defined eligibility criteria and critically appraised by established instruments. The substantial heterogeneity of included studies precluded meta-analyses and, therefore, narrative synthesis of quantitative and qualitative data was performed.

RESULTS

We found 23 studies providing eligible primary data on symptom-specific severity of food allergic reactions, and 31 previously published symptom-severity scoring systems referred to food allergic reactions. There were seven studies which assessed quality-of-life measures in patients (and family members) with different food allergy severity and two studies that investigated the economic burden of food allergy severity. Overall, the quality and the global rating of all included studies were judged as being moderate.

CONCLUSIONS

There is heterogeneity among severity scoring systems used and even outcomes considered in the context of severity of food allergy. No score has been validated. Our results will be used to inform the development of an international consensus to define the severity of food allergy.

SYSTEMATIC REVIEW REGISTRATION

A protocol was prospectively registered with the International Prospective Register of Systematic Reviews (PROSPERO) database with the registration number CRD42020183103 (https://www.crd.york.ac.uk/prospero/#recordDetails).

Comorbidities and Cofactors of Anaphylaxis in Patients with Moderate to Severe Anaphylaxis. Analysis of Data from the Anaphylaxis Registry for West Pomerania Province, Poland

Anaphylaxis is a severe, potentially life-threatening systemic hypersensitivity reaction that is still rarely diagnosed. For safety reasons, patients should visit an allergologist to identify potential causes and cofactors of this reaction. This paper presents the analysis of data from the Anaphylaxis Registry gathered over ten years at the Allergy Clinic, Pomeranian Medical University (PMU). A questionnaire-based survey was used for patients visiting the Allergy Clinic to identify potential augmentation factors/comorbidities and/or cofactors of anaphylaxis in patients with a history of moderate to severe anaphylaxis. The registry comprised patients with grade II or higher anaphylaxis. The gathered data concerned chronic comorbidities (cardiovascular diseases, respiratory diseases, and others), recurrence of anaphylaxis, and potential cofactors in anaphylaxis. In the analyzed group, the incidence rate of anaphylaxis was the highest for women aged 19–60 years. Most common comorbidities in patients with moderate to severe anaphylaxis included: cardiovascular diseases, respiratory tract diseases, features of atopy, and thyroid diseases. More than 30% of drug-induced reactions were anaphylactic reactions due to the re-exposure to the same drug, which points to the need for educational initiatives in this area. The incidence rate of anaphylaxis induced by Hymenoptera stings was comparable in patients who had a previous generalized reaction and those who had good tolerance to the previous sting. It is important to take these cofactors into consideration when evaluating patients with anaphylaxis as they may play a role in future anaphylactic reactions.

Risk Factors for Severe Anaphylaxis in Children

OBJECTIVE

To identify risk factors associated with severe anaphylaxis in children.

STUDY DESIGN

We carried out a multicenter prospective observational study including children less than 18 years old diagnosed with anaphylaxis in 7 Spanish pediatric emergency departments (EDs) between May 2016 and April 2018. Children were considered to have severe anaphylaxis if they met one or more of the following criteria: requirement for 2 or more doses of epinephrine, clinically important biphasic reaction, endotracheal intubation, intensive care unit admission, and/or death.

RESULTS

We included 453 episodes of anaphylaxis. Of these, 61 were classified as severe anaphylaxis (13.5%, 95% CI [10.6-16.9]): 53 (11.7%) required more than 1 dose of epinephrine, and there were 14 (3.1%) cases of clinically important biphasic reactions, 2 (0.4%) intubations in the ED, and 6 (1.3%) admissions to the intensive care unit. No patients died. In the multivariable regression, we identified 5 independent risk factors for severe anaphylaxis: history of asthma (P = .002; OR 2.705, 95% CI [1.431-5.113]), onset of the symptoms less than 5 minutes after the allergen exposure (P = .002; OR 2.619, 95% CI [1.410-4.866]), non-well appearance (P = .005; OR 2.973, 95% CI [1.380-6.405]), tachycardia (P = .014; OR 2.339, 95% CI [1.191-4.959]), and hypotension (P = .036; OR 3.725, 95% CI [1.087-12.762]).

CONCLUSIONS

Childhood anaphylaxis is usually well controlled in the ED. Children with a history of asthma, rapid onset of the symptoms, who are non-well appearing, or have tachycardia or hypotension upon arrival to the ED are more likely to have severe episodes.

Vaccine-related Anaphylaxis Cases Confirmed by KCDC from 2001-2016

BACKGROUND

A national immunization program (NIP) to prevent disease and reduce mortality from vaccine preventable diseases (VPD) is very important.

METHODS

We analyzed only the anaphylaxis cases that occurred between 2001 and 2016 that Korea Centers for Disease Control and Prevention (KCDC) determined had a definite causal relationship with a vaccine. The clinical symptoms were assessed according to the Brighton Collaboration case definition (BCCD) level.

RESULTS

During the period, there were 13 cases of vaccine-related anaphylaxis. The median age was 9 years (range, 1 month to 59 years). The incidence of anaphylaxis per million doses was 0.090 in 2005, 0.079 in 2012, 0.071 in 2013, 0.188 in 2015, and 0.036 in 2016. Of those cases, 23.1% were influenza vaccines, and 76.9% were BCCD level 2. Epinephrine was used in 46.2%.

CONCLUSION

Vaccine-related anaphylaxis seems to have been very rare in the past, but health care professionals must always be aware of anaphylaxis.

Health and Economic Outcomes of Home Maintenance Allergen Immunotherapy in Select Patients with High Health Literacy during the COVID-19 Pandemic: A Cost-Effectiveness Analysis During Exceptional Times

BACKGROUND

Allergen immunotherapy (AIT) is safe and effective but is typically administered under strict clinic observation to mitigate the risk of a systemic reaction to immunotherapy (SRIT). However, in the setting of the global coronavirus disease 2019 pandemic, alternative care models should be explored.

OBJECTIVE

To evaluate the cost-effectiveness of home immunotherapy self-administration (HITSA) in a highly idealized circumstance for provision of maintenance AIT in a shelter-in-place or other scenarios of unforeseen reduction in nonessential medical services.

METHODS

Markov modeling was used to compare in-office clinic AIT in selected patients using cohort analysis and microsimulation from the societal and health care perspectives.

RESULTS

Assuming similar SRIT rates, HITSA was found to be a cost-effective option with an incremental cost-effectiveness ratio of $44,554/quality-adjusted life-year when considering both incremental epinephrine autoinjector costs and coronavirus disease 2019 risks. Excluding epinephrine autoinjector costs, HISTA dominated other options. However, outside of pandemic considerations, HITSA was not cost-effective (incremental cost-effectiveness ratio, $198,877,286) at annual epinephrine autoinjector costs above $287. As the incremental HITSA SRIT rate increased above 15%, clinic AIT was the most cost-effective strategy. Excluding both pandemic risks and risk of motor vehicle accident fatality from round-trip clinic transit, clinic AIT dominated other strategies. Clinic AIT was the more cost-effective option at very high fatality relative risk for HITSA or at very low annual risk of contracting coronavirus disease 2019.

CONCLUSIONS

Under idealized assumptions HITSA can be a safe and cost-effective option during a global pandemic in appropriately selected patients provided home rates of SRIT remain stable.

Drug-Induced Anaphylaxis: An Update on Epidemiology and Risk Factors

Drug hypersensitivity is one of the most frequent causes of anaphylaxis, particularly in adults and in hospitalized patients. Drug-induced anaphylaxis (DIA) is also associated with more severe outcomes than other anaphylaxis triggers, and drugs are responsible for the majority of deaths due to anaphylaxis. We here review the current knowledge on the incidence, prevalence, drugs involved, mortality, and mortality risk factors for DIA. The incidence of both anaphylaxis and DIA seems to be increasing worldwide. Antibiotics and analgesics are the most frequently reported triggers of DIA. However, the importance of other drug groups should be taken into account, especially in particular settings (e.g., peri-operative and oncology). The identification of risk factors, geographical variables, and drugs associated with higher risk for DIA may improve the outcomes of this entity.

Anaphylaxis-a 2020 practice parameter update, systematic review, and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) analysis

Anaphylaxis is an acute, potential life-threatening systemic allergic reaction that may have a wide range of clinical manifestations. Severe anaphylaxis and/or the need for repeated doses of epinephrine to treat anaphylaxis are risk factors for biphasic anaphylaxis. Antihistamines and/or glucocorticoids are not reliable interventions to prevent biphasic anaphylaxis, although evidence supports a role for antihistamine and/or glucocorticoid premedication in specific chemotherapy protocols and rush aeroallergen immunotherapy. Evidence is lacking to support the role of antihistamines and/or glucocorticoid routine premedication in patients receiving low- or iso-osmolar contrast material to prevent recurrent radiocontrast media anaphylaxis. Epinephrine is the first-line pharmacotherapy for uniphasic and/or biphasic anaphylaxis. After diagnosis and treatment of anaphylaxis, all patients should be kept under observation until symptoms have fully resolved. All patients with anaphylaxis should receive education on anaphylaxis and risk of recurrence, trigger avoidance, self-injectable epinephrine education, referral to an allergist, and be educated about thresholds for further care.

Managing food allergy and anaphylaxis: A new model for an integrated approach

There is an increasing public concern on food allergy and related anaphylactic reactions that occur mainly at the community level. The perception of the disease is huge among parents who believe that 1 out of 20 children suffers from severe food allergy. The discrepancy between this self-reported prevalence and the real one when a food challenge is performed, points out the gap in the implementation of guidelines for clinical practice. Health professionals as well show scarce adherence to the guidelines both at the Emergency Departments and at the primary care level. Anaphylactic reaction are not recognized, adrenaline is under-used and self-injectable devices are not prescribed. Although education and training are limited to local, spontaneous initiatives from patient's organization and few allergists, the data so far available demonstrate that improvement in knowledge and attitudes can be achieved further to a structured program. There is the need to establish good evidence -based practices for educational intervention that should be adopted in the context of public health policies for food allergy. This would imply a change in legislation in many countries to prevent prosecution for liability of lay people administering adrenaline when properly trained. In parallel an integrated clinical care pathway should be developed by multidisciplinary and multi-professional teams in the context of national Centres of Excellence -CoE. These CoE could drive the progression to digital health create, creating networks of CoE for best practices of care and for clinical trials.

Recurrent anaphylaxis in the United States: time of onset and risk factors

BACKGROUND

Studies have not yet examined the trends and risk factors of biphasic and recurrent anaphylaxis in the United States using International Classification of Diseases, tenth revision (ICD-10) CM codes. The goal of this study is to examine the trends of biphasic and recurrent anaphylaxis in all patient care settings (inpatient, outpatient, emergency department, and observation).

METHODS

We used the Clinformatics database from 2015 to 2017. Our main outcome measure was recurrent anaphylactic events occurring within 1 year after the initial event. We used Cox proportional hazards modeling to assess the factors associated with recurrent anaphylaxis and the Kaplan-Meier method to estimate time to recurrence.

RESULTS

There were a total of 19,039 patients with incident anaphylaxis in 2016 and, of these, 2017 had a recurrent anaphylaxis event in the 12-month period after the index date (10.6%). The most common trigger for recurrent anaphylaxis is venom followed by food allergens. Pediatric patients aged <18 years were more likely to develop recurrent anaphylaxis compared with patients aged 18 to 64 years (hazard ratio [HR], 1.53). Patients with allergic rhinitis and asthma were more likely to develop recurrent anaphylaxis compared to those without these comorbidities (HR, 1.15 and 1.27, respectively).

CONCLUSION

This is the first national study using ICD-10 CM codes looking at rates of biphasic and recurrent anaphylaxis in all patient care settings. Recurrent anaphylaxis is more common in the first 3 days after the initial event, in younger patients (<18 years), and in patients with allergic rhinitis and/or asthma. Physicians need to prescribe epinephrine auto-injectors and educate their patients about the risk of recurrence.

Estimation of Health and Economic Benefits of Clinic Versus Home Administration of Omalizumab and Mepolizumab

BACKGROUND

Biologic therapy is a paradigm-shifting management strategy for many patients with asthma and chronic urticaria, but concerns for therapy-associated anaphylaxis may limit access to these therapies for patients unable to travel to medical clinics.

OBJECTIVE

To characterize the cost-effectiveness of in-clinic versus at-home biologic therapy with omalizumab and mepolizumab.

METHODS

Economic evaluation using microsimulations was performed from societal and health care sector perspectives for patients with asthma or chronic spontaneous urticaria receiving omalizumab or mepolizumab in an allergy clinic, primary care provider (PCP) office, or at home over a 1-year time horizon (12 injections per year in each base case with sensitivity analysis to 24 injections per year). Travel times and distances were applied to a population attending a tertiary care allergy clinic in Northern New England receiving omalizumab or mepolizumab, using a willingness-to-pay value of $10 million per death prevented and in-clinic administration reducing anaphylaxis fatality and hospitalization 10- to100-fold. Deterministic and probabilistic sensitivity analyses were performed.

RESULTS

One-way allergy clinic travel distances significantly exceeded local PCP offices (49 miles, 95% CI, 42-56, vs 12 miles, 95% CI, 10-15). In the omalizumab societal analysis, annual PCP and allergy clinic administration cost $1369.14 (mean) ± $51.33 (SD) and $1916.68 ± $40.86, respectively. Small reductions in medication-related fatalities with in-clinic administration were offset by the potential increase in automobile fatalities resulting from traveling to the allergy clinic (14.6 ± 15.0 per million person-years for this strategy). Compared with at-home administration, in-clinic omalizumab administration was not cost-effective, with an incremental cost-effectiveness ratio of $500,648,430 (PCP), and with allergy clinic administration dominated by higher costs and automobile-related fatalities. Routine mepolizumab clinic administration was dominated by at-home administration unless anaphylaxis rates or self-administration teaching costs were high.

CONCLUSIONS

For many patients, at-home administration of omalizumab or mepolizumab may be a cost-effective strategy.

The cost-effectiveness of requiring universal vs contextual self-injectable epinephrine autoinjector for allergen immunotherapy

BACKGROUND

Aeroallergen immunotherapy (AIT) is a safe and effective disease-modifying treatment associated with rare therapy-associated fatality. Significant practice variation surrounds universal or contextual prescription of self-injectable epinephrine (SIE) for patients receiving AIT.

OBJECTIVE

To characterize the cost-effectiveness of a universal vs contextual SIE requirement for patients receiving AIT.

METHODS

An economic evaluation using cohort and microsimulation was performed from both the societal and health care sector perspectives for patients undergoing AIT, assessing a universal requirement to fill SIE prescriptions at the outset of therapy compared with requiring this only after a systemic reaction to immunotherapy (SRIT).

RESULTS

A universal SIE requirement for AIT is not cost-effective, with the incremental cost-effectiveness ratio for this strategy estimated at $669,327,730 per quality-adjusted life-year (QALY). In the microsimulation (n = 10,000), the mean (SD) costs of a universal approach exceeded that of a more context-specific strategy where SIE was only prescribed for patients after an initial SRIT ($19,653.36 [$4296.66] vs $16,232.14 [$5204.32]), and given the effects on rates of AIT discontinuation, the universal approach was less effective (mean [SD], 25.555 [2.285] QALYs) compared with a contextualized approach (mean [SD], 25.579 [2.345] QALYs). Universal SIE prescription could be cost-effective if it provided a 1000 times protection against AIT fatality at a value-based cost of $24, and the annual AIT fatality rates unrealistically exceed 2.6 per 10,000 patients.

CONCLUSION

In a simulation of potential SIE-prescribing strategies for patients receiving AIT, a universal approach to an epinephrine autoinjector requirement was not cost-effective when compared with an approach in which an SIE is prescribed only to patients with prior SRIT.

Vaccine-associated hypersensitivity

Vaccine-associated hypersensitivity reactions are not infrequent; however, serious acute-onset, presumably IgE-mediated or IgG and complement-mediated anaphylactic or serious delayed-onset T cell-mediated systemic reactions are considered extremely rare. Hypersensitivity can occur because of either the active vaccine component (antigen) or one of the other components. Postvaccination acute-onset hypersensitivity reactions include self-limited localized adverse events and, rarely, systemic reactions ranging from urticaria/angioedema to full-blown anaphylaxis with multisystem involvement. Risk of anaphylaxis after all vaccines is estimated to be 1.31 (95% CI, 0.90-1.84) per million vaccine doses, respectively. Serious hypersensitivity reactions after influenza vaccines are particularly important because of the large number of persons vaccinated annually. Influenza vaccines are unique in requiring annual changes in the vaccines' antigenic composition to match the predicted circulating influenza strains. Recently, novel influenza vaccine types were introduced in the United States (recombinant vaccines, some with higher antigen content and a new adjuvanted vaccine). Providers should be aware of changing recommendations on the basis of recent published evidence for persons with a history of egg allergy to receive annual influenza vaccination. Further research is needed to elucidate the pathophysiology and risk factors for reported vaccine-associated adverse events. Further research is also needed to determine whether repeated annual inactivated influenza vaccination, the number of vaccine antigens administered at the same time, and the current timing of routine infant vaccinations are optimal for overall population well-being.