A population-based epidemiologic study of emergency department visits for anaphylaxis in Florida. J Allergy Clin Immunol. 2011;128:594-600.e1. [PMID: 21714994 DOI: 10.1016/j.jaci.2011.04.049]

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.

Anaphyl-Crisis: Rising Rates of Pediatric Anaphylaxis

OBJECTIVES

Anaphylaxis is a serious allergic reaction that has the potential to be life-threatening if not recognized and managed rapidly. Several regional studies have shown increased incidence of anaphylaxis over the past decade. The objectives of this study were to determine rates of pediatric anaphylaxis in southeast Michigan between January 1, 2010, and December 31, 2019, and to describe the epidemiology of pediatric patients presenting to emergency centers in southeast Michigan with anaphylaxis.

METHODS

We performed a retrospective chart review of all pediatric patients aged 0 to 17 years presenting to 2 large emergency centers from 2010 to 2019 with a diagnosis of anaphylaxis using International Classification of Diseases , Ninth and Tenth Revision , Clinical Modification codes. Epidemiological and visit data, including length of stay, use of intravenous medication, and emergency severity index, were extracted and analyzed. Pediatric anaphylaxis rates were calculated based on detected anaphylaxis cases divided by total pediatric emergency department visits to the 2 emergency centers. A Poisson regression model was used to predict rates of anaphylaxis per 100,000 emergency department visits.

RESULTS

One thousand three hundred ninety-one pediatric visits for anaphylaxis were identified during a period between January 1, 2010, and December 31, 2019. There was a significant rate of increase in pediatric anaphylaxis cases over the 10-year study period at both suburban emergency centers, with an annual increase of 21% and 13%. There was no significant change in trends in demographic factors. Most anaphylaxis cases were young, White males with private insurance. Most children did not receive intravenous medications (77%). The median length of stay increased by 1.5 hours over the study period and 92% of patients were discharged home.

CONCLUSIONS

Pediatric emergency center visits and length of stay for anaphylaxis in southeast Michigan have markedly increased over the past 10 years.

Improving epinephrine autoinjector usability and carriage frequency among patients at risk of anaphylaxis: a quality improvement initiative

Although epinephrine autoinjectors (EAIs) are crucial for the management of anaphylaxis, patient carriage frequency of EAI is as low as 57% and usage of EAIs is erroneous 35%–43% of the time. Our objective was to improve patient carrying frequency of EAI and understanding of EAI usage.

We implemented a quality improvement initiative using consistent closed-loop education, redesigned clinic workflow, electronic medical record reminder-based interventions, and educational materials to improve patient EAI carriage compliance and understanding of EAI indications and proper technique.

The percentage of our patients who carried the EAI at all times increased from 55% to 93% in 6 months. Participants knowledge of EAI indications also improved from 22% to 91%. Patient demonstration scores of the EAI device improved from 21% to 91% as well.

Our quality improvement interventions demonstrated a significant improvement>80% in EAI carriage frequency, knowledge of indications, and proper device technique.

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.

Acute Urticaria and Anaphylaxis: Differences and Similarities in Clinical Management

Acute urticaria is a common condition that presents with wheals and/or angioedema. However, these symptoms are also frequent in anaphylaxis, a life-threatening reaction that should be immediately diagnosed and treated. In both, mast cells play a central role in the physiopathology. Causes and triggers of acute urticaria and anaphylaxis are similar in general, but some peculiarities can be observed. The diagnostic approach may differ, accordingly to the condition, suspicious causes, age groups and regions. Adrenaline is the first-line treatment for anaphylaxis, but not for acute urticaria, where H1-antihistamines are the first choice. In this paper, we review the main aspects, similarities and differences regarding definitions, mechanisms, causes, diagnosis and treatment of acute urticaria and anaphylaxis.

Evaluation of adrenaline auto-injector prescription profiles: A population-based, retrospective cohort study within the National Insurance Claims Database of Japan

BACKGROUND

Adrenaline is the first-line medication for managing anaphylaxis. A better understanding of prescription trends for adrenaline auto-injectors (AAIs) is important to improving patient care as well as information on health education interventions and medical guidelines. However, it has been difficult to gather comprehensive data in a sustainable manner. Thus, we aimed to investigate trends in AAI prescriptions in Japan.

METHODS

We searched the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB), a unique and comprehensive database of health insurance claims, and investigated prescriptions for AAIs for all ages (April 2017 to March 2018). We assessed the annual number of prescriptions per person as well as prescription rates per 100,000 population per year by age, sex, and geographic region.

RESULTS

A total of 88,039 subjects (56,109 males, 31,930 female) and 116,758 devices (1.33 AAIs per patient per year) were prescribed AAIs at least once a year for all ages. The prescription rate for AAIs was 69.5 per 100,000 population-years. Patients aged 0-9 years were prescribed AAIs at the rate of 278.9 per 100,000 population-years. Patients aged 0-19 years were 6.4 times more likely to be prescribed AAIs than those over 20 years of age. Males were more frequently prescribed AAIs than females in all age groups, except for those aged 20-24 years. We also evaluated differences in prescription rates by geographic region.

CONCLUSIONS

This comprehensive evaluation revealed trends in AAI prescriptions, thus helping develop preventive strategies with respect to anaphylaxis in Japan.

ICD-10 anaphylaxis algorithm and the estimate of vaccine-attributable anaphylaxis incidence in Medicare

BACKGROUND

Anaphylaxis is a rare, serious allergic reaction. Its identification in large healthcare databases can help better characterize this risk.

OBJECTIVE

To create an ICD-10 anaphylaxis algorithm, estimate its positive predictive values (PPVs) in a post-vaccination risk window, and estimate vaccination-attributable anaphylaxis rates in the Medicare Fee For Service (FFS) population.

METHODS

An anaphylaxis algorithm with core and extended portions was constructed analyzing ICD-10 anaphylaxis claims data in Medicare FFS from 2015 to 2017. Cases of post-vaccination anaphylaxis among Medicare FFS beneficiaries were then identified from October 1, 2015 to February 28, 2019 utilizing vaccine relevant anaphylaxis ICD-10 codes. Information from medical records was used to determine true anaphylaxis cases based on the Brighton Collaboration's anaphylaxis case definition. PPVs were estimated for incident anaphylaxis and the subset of vaccine-attributable anaphylaxis within a 2-day post-vaccination risk window. Vaccine-attributable anaphylaxis rates in Medicare FFS were also estimated.

RESULTS

The study recorded 66,572,128 vaccinations among 21,685,119 unique Medicare FFS beneficiaries. The algorithm identified a total of 190 suspected anaphylaxis cases within the 2-day post-vaccination window; of these 117 (62%) satisfied the core algorithm, and 73 (38%) additional cases satisfied the extended algorithm. The core algorithm's PPV was 66% (95% CI [56%, 76%]) for identifying incident anaphylaxis and 44% (95% CI [34%, 56%]) for vaccine-attributable anaphylaxis. The vaccine-attributable anaphylaxis incidence rate after any vaccination was 0.88 per million doses (95% CI [0.67, 1.16]).

CONCLUSION

The ICD-10 claims algorithm for anaphylaxis allows the assessment of anaphylaxis risk in real-world data. The algorithm revealed vaccine-attributable anaphylaxis is rare among vaccinated Medicare FFS beneficiaries.

Identification and Validation of Anaphylaxis Using Electronic Health Data in a Population-based Setting

BACKGROUND

Anaphylaxis is a life-threatening allergic reaction that is difficult to identify accurately with administrative data. We conducted a population-based validation study to assess the accuracy of ICD-10 diagnosis codes for anaphylaxis in outpatient, emergency department, and inpatient settings.

METHODS

In an integrated healthcare system in Washington State, we obtained medical records from healthcare encounters with anaphylaxis diagnosis codes (potential events) from October 2015 to December 2018. To capture events missed by anaphylaxis diagnosis codes, we also obtained records on a sample of serious allergic and drug reactions. Two physicians determined whether potential events met established clinical criteria for anaphylaxis (validated events).

RESULTS

Out of 239 potential events with anaphylaxis diagnosis codes, the overall positive predictive value (PPV) for validated events was 64% (95% CI = 58 to 70). The PPV decreased with increasing age. Common precipitants for anaphylaxis were food (39%), medications (35%), and insect bite or sting (12%). The sensitivity of emergency department and inpatient anaphylaxis diagnosis codes for all validated events was 58% (95% CI = 51 to 65), but sensitivity increased to 95% (95% CI = 74 to 99) when outpatient diagnosis codes were included. Using information from all validated events and sampling weights, the incidence rate for anaphylaxis was 3.6 events per 10,000 person-years (95% CI = 3.1 to 4.0).

CONCLUSIONS

In this population-based setting, ICD-10 diagnosis codes for anaphylaxis from emergency department and inpatient settings had moderate PPV and sensitivity for validated events. These findings have implications for epidemiologic studies that seek to estimate risks of anaphylaxis using electronic health data.

U.S. Population-Based background incidence rates of medical conditions for use in safety assessment of COVID-19 vaccines

The Coronavirus Disease 2019 (COVID-19) pandemic has had a devastating impact on global health, and has resulted in an unprecedented, international collaborative effort to develop vaccines to control the outbreak, protect human lives, and avoid further social and economic disruption. Mass vaccination campaigns are underway in multiple countries and are expected worldwide once more vaccine becomes available. Some early candidate vaccines use novel platforms, such as mRNA encapsulated in lipid nanoparticles, and relatively new platforms, such as replication-deficient viral vectors. While these new vaccine platforms hold promise, limited safety data in humans are available. Serious health outcomes linked to vaccinations are rare, and some outcomes may occur incidentally in the vaccinated population. Knowledge of background incidence rates of these medical conditions is a critical component of vaccine safety monitoring to aid in the assessment of adverse events temporally associated with vaccination and to put these events into context with what would be expected due to chance alone. A list of 22 potential adverse events of special interest (AESI), including neurologic, autoimmune, and cardiovascular disorders, was compiled by subject matter experts at the U.S. Food and Drug Administration and the Centers for Disease Control and Prevention. The most recently available U.S. background rates for these medical conditions, overall and by age, sex, and race/ethnicity (when available), were sourced from reported statistics (data published by medical panels/ associations or federal government reports), and literature reviews in PubMed. This review provides estimates of background incidence rates for medical conditions that may be monitored or studied as AESI during safety surveillance and research for COVID-19 vaccines and other new vaccines.

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.

Increasing anaphylaxis events in Western Australia identified using four linked administrative datasets

Background

Anaphylaxis events are increasing worldwide, based on studies of single administrative datasets including hospital admissions, emergency room presentations, and prescription and medical claims data. Linking multiple administrative datasets may provide better epidemiological estimates, by capturing a greater number of anaphylaxis events occurring at the individual level. In this linked data study in Western Australia, we combined 4 population-based datasets to identify anaphylaxis events, factors influencing occurrence, and change in event rates from 2002 to 2013.

Methods

Four linked administrative datasets from the Western Australian Data Linkage System were used, representing ambulance attendances, emergency department presentations, hospital inpatient admissions and death registrations. An anaphylaxis cohort was identified using ICD-9-CM, ICD-10-AM and additional anaphylaxis diagnosis codes, with event rates calculated. We explored the impact of age, gender, cause, Indigenous status and socioeconomic index on event rates. Standard Poisson regression models were used to examine the significance of the change in anaphylaxis event rates over time.

Results

A total 12,637 individuals (mean age 31.8 years, 49.6% female) experienced 15,462 anaphylaxis events between 2002 and 2013 (97.5% in non-Indigenous patients and 59.5% residing in the area of greatest socioeconomic advantage). Anaphylaxis event rates increased from 15.4 to 82.5/10⁵ population between 2002 and 2013. The greatest increase in anaphylaxis events was seen in those coded as unspecified anaphylaxis (all ages, males and females combined, p < 0.001), with the highest rates of unspecified anaphylaxis in males 0–4 years (171.9/10⁵ population in 2013), and females 15–19 years (104.0/10⁵ in 2013). The average annual percent increase (95% CI) for food-related anaphylaxis was 9.2% (6.6–12.0); for medication-related anaphylaxis was 5.8% (4.5–7.1); and for unspecified anaphylaxis was 10.4% (9.8–11.0); all p < 0.001. There was a significant increase in ambulance attendance, emergency presentations and inpatient admissions for anaphylaxis between 2002 and 2013, with emergency presentations (56.0/10⁵ population), inpatient admissions (43.2/10⁵), and ambulance attendance (21.6/10⁵) highest in 2013. Only 25 anaphylaxis-related deaths were recorded in the mortality register with no significant change in rates over time.

Conclusion

Using multiple linked administrative datasets, we identified significantly higher rates of total anaphylaxis than previously reported, with more than 5-fold increases in anaphylaxis events between 2002 and 2013. While the combination of 4 population-level datasets provides a more comprehensive capture of cases, even at the individual dataset level, admission rates for anaphylaxis in Western Australia are substantially higher than those previously reported for similar time periods, both in Australia and worldwide.

Overview of registries for anaphylaxis: a scoping review protocol

OBJECTIVE

This review will describe the scope and operational features of global registries for anaphylaxis and assess their contribution to improving knowledge and care of anaphylaxis by measuring their research output.

INTRODUCTION

The incidence of anaphylaxis is increasing around the world. Structured reporting systems, such as patient registries, are needed to better understand the burden of anaphylaxis and protect the growing number of allergic patients.

INCLUSION CRITERIA

The concept to be mapped is registries across the world that enroll patients who have experienced anaphylaxis. Published and gray literature sources will be considered if they describe the scope and operational features of anaphylaxis registries. Only full-text studies published in English will be included. There will be no date restriction.

METHODS

The JBI methodology for scoping reviews will be followed. Embase, MEDLINE, Scopus, and CINAHL will be searched from inception date for relevant articles. Identified keyword and index terms will be adapted for searches of gray literature sources, using Google advanced search functions. The authors and developers of identified registries will be contacted, where possible, to obtain additional information about the development and structure of systems. Data will be extracted by two independent reviewers. Any discrepancies will be resolved by a third reviewer. Tables and a narrative summary will be used to describe and compare the scope and features of anaphylaxis registries and outline their output to assess their contribution to research, clinical practice, and public health policy for anaphylaxis.

Food allergy epidemiology and racial and/or ethnic differences

In recent decades, immunoglobulin E (IgE) mediated food allergy has become a growing public health concern. Converging evidence from cross-sectional prevalence studies, health care utilization records, and cohort studies indicate that food allergies are increasingly prevalent and often severe. Although IgE-mediated food allergy has long been considered a predominantly pediatric concern, analysis of recent self-reported data suggests that food allergies may be more prevalent among adult populations than previously acknowledged, with many reported cases of adult-onset allergies as well as persistent childhood-onset allergies. Results of studies also suggest that food allergy-related health care utilization is increasing as more individuals seek emergency treatment for food-induced anaphylaxis. Analysis of epidemiologic data also indicates that the burden of food allergies is unequally distributed. Published prevalence rates are highest in Western countries, e.g., the United States, United Kingdom, and Australia. Within these countries, there also is heterogeneity across racial and/or ethnic groups, with non-White and second-generation immigrant populations disproportionately affected. Importantly, such observations can shed light on the etiology of food allergy and inform improved clinical management, treatment, and prevention efforts. For example, there is a growing consensus that earlier introduction of allergenic foods, e.g., peanut, promotes oral tolerance and can dramatically reduce food allergy risk. In addition, much attention has been paid to the potentially deleterious effects of cutaneous allergen exposure, e.g., through eczematous skin, which can skew the immune response away from tolerance and toward allergic sensitization, thereby increasing food allergy risk. Furthermore, there is a growing appreciation for the potential protective effects of diverse microbial exposures, given mounting evidence for the immunomodulatory effects of the human microbiome. Also, when considering the geographic variability in the prevalence of certain food and environmental allergies as well as their structural similarities at the molecular level, it is believed that co-sensitization between food and environmental allergens may be a key driver of rising food allergy prevalence.

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.

Simulation of Health and Economic Benefits of Extended Observation of Resolved Anaphylaxis

IMPORTANCE

Biphasic anaphylaxis may occur in up to 20% of patients with anaphylaxis; however, the optimal observation time of patients with resolved anaphylaxis is unknown.

OBJECTIVE

To characterize the cost-effectiveness of short vs prolonged medical observation times after resolved anaphylaxis.

DESIGN, SETTING, AND PARTICIPANTS

An economic evaluation was performed of computer-simulated adult patients observed in outpatient allergy clinics and emergency departments, with rates of biphasic anaphylaxis derived from a 2019 meta-analysis.

EXPOSURES

Computer-simulated patients (10 000 per strategy) were randomized to undergo 1 hour of medical observation (associated with 95% negative predictive value of biphasic anaphylaxis) or 6 or more hours of observation (associated with a 97.3% negative predictive value of biphasic anaphylaxis).

MAIN OUTCOMES AND MEASURES

Cost-effectiveness of 6- to 24-hour medical observation of resolved anaphylaxis evaluated at willingness-to-pay thresholds of $10 000 per case of biphasic anaphylaxis observed and $10 million per death prevented, assuming that observation is associated with a 10- to 1000-fold reduction in the risk of death due to biphasic anaphylaxis.

RESULTS

Biphasic anaphylaxis occurred after hospital discharge in 365 patients observed for 1 hour and in 213 patients undergoing prolonged observation. From a health care sector perspective, with medical observation costs of $286.92 per hour, the incremental cost of extended medical observation of resolved anaphylaxis (1 hour vs 6 hours) was $62 374 per case of biphasic anaphylaxis identified ($68 411 from the societal perspective). In Monte Carlo simulations, with hourly costs ranging from $100 to $500 and extended observation ranging from 6 to 24 hours (health care sector perspective), the mean (SD) costs were $295.36 ($81.22) for 1 hour of observation vs $3540.42 ($1626.67) for extended observation. The incremental cost-effectiveness ratio was $213 439 per biphasic anaphylaxis observed ($230 202 from the societal perspective). A 6-hour observation could be cost-effective if the risk of biphasic anaphylaxis after 1-hour observation of resolved anaphylaxis was 17% or if hourly observation costs were less than $46 in the base case. Cost-effectiveness could also be achieved (willingness-to-pay of $10 million per death prevented, health care sector perspective) when a baseline fatality rate of 0.33% per biphasic anaphylactic event was assumed, with a no greater than 24% relative risk of fatality associated with 6-hour observation.

CONCLUSIONS AND RELEVANCE

This study indicates that prolonged medical observation (6-24 hours) for resolved anaphylaxis may not be cost-effective for patients at low risk for biphasic anaphylaxis; however, in particular clinical circumstances of low observation costs, high postdischarge risk of biphasic anaphylaxis, or large incremental fatality risk reduction associated with extended observation, longer medical observation can be justified.

Serological investigation of IgG and IgE antibodies against food antigens in patients with inflammatory bowel disease

BACKGROUND

Food antigens have been shown to participate in the etiopathogenesis of inflammatory bowel disease (IBD), but their clinical value in IBD is still unclear.

AIM

To analyze the levels of specific immunoglobulin G (IgG) and E (IgE) antibodies against food antigens in IBD patients and to determine their clinical value in the pathogenesis of IBD.

METHODS

We performed a retrospective study based on patients who visited the First Affiliated Hospital of Nanjing Medical University between August 2016 and January 2018. A total of 137 IBD patients, including 40 patients with ulcerative colitis (UC) and 97 patients with Crohn’s disease (CD), and 50 healthy controls (HCs), were recruited. Serum food-specific IgG antibodies were detected by semi-quantitative enzyme-linked immunosorbent assay, and serum food-specific IgE antibodies were measured by Western blot. The value of food-specific IgG antibodies was compared among different groups, and potent factors related to these antibodies were explored by binary logistic regression.

RESULTS

Food-specific IgG antibodies were detected in 57.5% of UC patients, in 90.72% of CD patients and in 42% of HCs. A significantly high prevalence and titer of food-specific IgG antibodies were observed in CD patients compared to UC patients and HCs. The number of IgG-positive foods was greater in CD and UC patients than in HCs (CD vs HCs, P = 0.000; UC vs HCs, P = 0.029). The top five food antigens that caused positive specific IgG antibodies in CD patients were tomato (80.68%), corn (69.32%), egg (63.64%), rice (61.36%), and soybean (46.59%). The foods that caused positive specific IgG antibodies in UC patients were egg (60.87%), corn (47.83%), tomato (47.83%), rice (26.09%), and soybean (21.74%). Significantly higher levels of total food-specific IgG were detected in IBD patients treated with anti-TNFα therapy compared to patients receiving steroids and immunosuppressants (anti-TNFα vs steroids, P = 0.000; anti-TNFα vs immunosuppressants, P = 0.000; anti-TNFα vs steroids + immunosuppressants, P = 0.003). A decrease in food-specific IgG levels was detected in IBD patients after receiving anti-TNFα therapy (P = 0.007). Patients who smoked and CD patients were prone to developing serum food-specific IgG antibodies [Smoke: OR (95%CI): 17.6 (1.91-162.26), P = 0.011; CD patients: OR (95%CI): 12.48 (3.45-45.09), P = 0.000]. There was no difference in the prevalence of food-specific IgE antibodies among CD patients (57.1%), UC patients (65.2%) and HCs (60%) (P = 0.831).

CONCLUSION

CD patients have a higher prevalence of food-specific IgG antibodies than UC patients and HCs. IBD patients are prone to rice, corn, tomato and soybean intolerance. Smoking may be a risk factor in the occurrence of food-specific IgG antibodies. Food-specific IgG antibodies may be a potential method in the diagnosis and management of food intolerance in IBD.

Urban/rural residence effect on emergency department visits arising from food-induced anaphylaxis

BACKGROUND

Anaphylaxis is a severe and potentially fatal allergic response. Early-life exposure to rural environments may help protect against allergic reaction. This study assesses urban/rural differences by age and race/ethnicity in emergency department (ED) pediatric visit rates for food-induced anaphylaxis.

METHODS

This observational study examined 2009-2014 inpatient and ED data from New York and Florida, using ICD-9-CM diagnostic code (995.6) to identify food-induced anaphylaxis cases <18 y/o. Primary predictor of interest was urban/rural setting, with race/ethnicity and age also evaluated. Associations between ED visit rates and urban/rural setting were evaluated by multivariable hierarchical negative binomial regression with state and year fixed effects.

RESULTS

ED visit rates (per 100,000) for food-induced anaphylaxis were 12.31 and 4.60 in urban and rural settings, respectively. Rates were highest among Blacks (15.26) younger urban children (17.29) and older rural children (6.99). Compared to rural, urban children had significantly higher anaphalaxis ED visit rates (IRR 2.77).

CONCLUSIONS

Food-induced anaphylaxis ED visit rates were highest among younger urban children and Black children, with a notable contrast in age distribution between urban and rural rates. Higher urban rates may be attributed to Hygiene Hypothesis, though racial, economic and emergency care access disparities may also influence these outcomes.

Understanding adverse drug-related emergency department visits: development of a conceptual model through a systematic review

Background

The burden of adverse drug event (ADE)-related emergency department (ED) visits is increasing despite several preventive measures. The objective of this paper was to develop and validate a conceptual model for a better understanding of ADE-related ED visits and to guide the design and implementation of effective interventions.

Methods

The development of the model involved a systematic review of the literature using PubMed and Embase databases. Studies reporting the risk factors associated with ADE-related ED visits were included. The methodological qualities of the included studies were assessed using the Mixed Methods Appraisal Tool (MMAT). The model was mapped and validated using face and content validity by an expert panel. Deficiencies and targeted interventions were identified, and steps for the design and implementation were recommended.

Results

The literature search generated 1361 articles, of which 38 were included in the review; 41 risk factors associated with ADE-related ED visits were identified. All factors were mapped, and the model was validated through face and content validity. The model consisted of six concepts related to sociodemographic factors, clinical factors, ADE-related to ED visits, ADE while in the ED, outcomes, and consequences. Interventions could be targeted at the factors identified in each concept to prevent ADE-related ED burden.

Conclusion

A conceptual model to guide the successful design and implementation of strategies to prevent ADE-related ED visits and the occurrence of ADE at ED was developed. Clinicians should take these factors into consideration to prevent untoward events, especially when treating high-risk patients.

A longitudinal study of hymenoptera stings in preschool children

BACKGROUND

Insect venom is the second most common cause of anaphylaxis outside of medical encounters. Stings cause over 20% of all anaphylactic deaths and 7% of anaphylaxis in children. To date, there have been no longitudinal studies of insect sting events or allergy in preschool children.

METHODS

A prospective longitudinal nested observational study in the BASELINE Birth Cohort Study (n = 2137). Sting-related questions were asked at 6 and 12 months and 2 and 5 years. Skin prick testing (SPT) was performed at 2 and 5 years. SpIgE testing was performed on selected cases at 2 years.

RESULTS

Seventy-seven children (6.8%) were stung by the age of 2. Of these, 25 (32.5%) reported adverse reactions (four systemic). Eleven (0.9%) had positive SPT at 2 years (eight bee, two wasp, one both). Four stung children had positive SPT. Two (one stung, one never stung) had positive spIgE to a venom component at 2 years. A total of 268 children (21.9%) were stung by 5 years, 144 (52.1%) reporting local reactions and none systemic. Four children (0.4%) had positive SPT at 5 years: one bee and three wasp. Of the 11 SPT-positive children at 2 years, none were still positive at 5 years.

CONCLUSION

This is the first longitudinal study of the natural history of hymenoptera stings and allergy in preschool children. Hymenoptera venom allergy is less common in this cohort than in adults. Systemic reactions were not medically documented in this population, in keeping with previous literature. This study confirms the poor correlation of IgE sensitization to venom with sting allergy and does not support the common parental request to screen children for sting allergy.

A survey of anaphylaxis etiology and treatment

Identifying the causes of anaphylaxis which is an acute, potentially fatal systemic reaction is very important in every community. Treatment strategies and pitfalls should also be determined. We sought to determine the most common triggers of anaphylaxis, clinical manifestations and treatment strategies in Mashhad, northeast of Iran. An observational cross-sectional study was conducted to evaluate all patients with a history of anaphylactic reaction who were referred to University Allergy Clinics between 2006 and 2016 in Mashhad Iran. We used a combination of patient’s clinical history and allergy diagnostic testing including radioallergosorbant test and skin prick test in order to determine the etiology of anaphylaxis. We identified 172 anaphylactic reactions in 70 patients. Median age was 15 years with a range from 6 months to 48 years. The triggers included: foods, 61.4%; drugs, 15.7%; hymenoptera venom, 8.6%; idiopathic, 5.7%; immunotherapy, 4.3% and other etiologies: 5.7%. Nuts and seeds were the most important triggers of food induced anaphylaxis, especially in school children, adolescents and young adults, followed by fruits. However, Cow’s milk and hen’s egg were the main triggers of anaphylaxis in children aged under 2 years. The most common symptoms were cutaneous and cardiovascular. Corticosteroids (94.3%) and/or antihistamines (85.7%) were used most frequently for treatment followed by intravenous fluids (54.3%), whereas epinephrine was only used in 17.1% of the cases. Food related anaphylaxis and other typical triggers of anaphylaxis are age dependent and the risks and triggers change with age. Epinephrine injection should be increased by improving the awareness of physician and medical teams. The study was approved by the Ethics Committee of the Faculty of Medicine of Mashhad University of Medical Sciences (approved number: IR.MUMS.REC.1393.960).

Common causes of emergency department visits for anaphylaxis in Korean community hospitals: A cross-sectional study

Anaphylaxis can cause death and requires immediate management. For prevention and education programs for anaphylaxis, it is important to be aware of the common triggering factors. We investigated the triggers of anaphylaxis in the emergency departments (EDs) of community hospitals in Korea.Patients who visited the EDs of 7 community hospitals for anaphylaxis from January 1, 2012 to December 31, 2016 were enrolled. Anaphylaxis was defined according to the World Allergy Organization criteria and identified via a thorough review of the medical records of patients who were diagnosed with anaphylaxis (ICD-10 codes: T780, T782, T805, and T886) at the ED or administered epinephrine in the ED. Triggers of anaphylaxis were also evaluated by a review of the medical records.We identified 1021 ED visits for anaphylaxis. The incidence of anaphylaxis ED visits was 0.08%. The triggers of ED visits for anaphylaxis were bee venom (55.0%), foods (21.3%), and drugs (13.2%); 9.6% of cases were idiopathic. However, food was the most common trigger among the patients aged <20 years old. The frequency of ED visits for anaphylaxis was highest in summer (47.9%), followed by autumn (28.2%), spring (12.3%), and winter (11.6%). The incidence of anaphylaxis ED visits was highest in August, during which bee venom was the trigger for 80% of anaphylaxis cases. For the 55 patients with repeat ED visits for anaphylaxis, Bee venom was also the most common trigger.The number of ED visits for anaphylaxis showed marked seasonal variation, peaking in summer. Bee venom was the most common trigger for adults and the main reason for seasonal variations of anaphylaxis ED visits in Korean community hospitals.

Drug-Induced Anaphylaxis Documented in Electronic Health Records

BACKGROUND

Although drugs represent a common cause of anaphylaxis, few large studies of drug-induced anaphylaxis have been performed.

OBJECTIVE

To describe the epidemiology and validity of reported drug-induced anaphylaxis in the electronic health records (EHRs) of a large United States health care system.

METHODS

Using EHR drug allergy data from 1995 to 2013, we determined the population prevalence of anaphylaxis including anaphylaxis prevalence over time, and the most commonly implicated drugs/drug classes reported to cause anaphylaxis. Patient risk factors for drug-induced anaphylaxis were assessed using a logistic regression model. Serum tryptase and allergist visits were used to assess the validity and follow-up of EHR-reported anaphylaxis.

RESULTS

Among 1,756,481 patients, 19,836 (1.1%) reported drug-induced anaphylaxis; penicillins (45.9 per 10,000), sulfonamide antibiotics (15.1 per 10,000), and nonsteroidal anti-inflammatory drugs (NSAIDs) (13.0 per 10,000) were most commonly implicated. Patients with white race (odds ratio [OR] 2.38, 95% CI 2.27-2.49), female sex (OR 2.20, 95% CI 2.13-2.28), systemic mastocytosis (OR 4.60, 95% CI 2.66-7.94), Sjögren's syndrome (OR 1.94, 95% CI 1.47-2.56), and asthma (OR 1.50, 95% CI 1.43-1.59) had an increased odds of drug-induced anaphylaxis. Serum tryptase was performed in 135 (<1%) anaphylaxis cases and 1,587 patients (8.0%) saw an allergist for follow-up.

CONCLUSIONS

EHR-reported anaphylaxis occurred in approximately 1% of patients, most commonly from penicillins, sulfonamide antibiotics, and NSAIDs. Females, whites, and patients with mastocytosis, Sjögren's syndrome, and asthma had increased odds of reporting drug-induced anaphylaxis. The low observed frequency of tryptase testing and specialist evaluation emphasize the importance of educating providers on anaphylaxis management.

Changes in emergency department concordance with guidelines for the management of stinging insect-induced anaphylaxis: 1999-2001 vs 2013-2015

BACKGROUND

Changes in emergency department (ED) concordance with guidelines for the management of stinging insect-induced anaphylaxis (SIIA) are not known.

OBJECTIVE

To describe temporal changes in ED concordance with guidelines for the management of SIIAs.

METHODS

We analyzed data from 2 multicenter retrospective studies of patients with stinging insect-related acute allergic reactions seen in 1 of 14 North American EDs during 2 periods: 1999 through 2001 and 2013 through 2015. Visits were identified similarly across studies (eg, using International Classification of Diseases, Ninth Revision, Clinical Modification codes 989.5, 995.0, and 995.3). Anaphylaxis was defined as an acute allergic reaction with involvement of at least 2 organ systems or hypotension. We compared concordance between periods with 4 guideline recommendations: (1) treatment with epinephrine, (2) discharge prescription for epinephrine auto-injector, (3) referral to an allergist/immunologist, and (4) instructions to avoid the offending allergen.

RESULTS

We compared 182 patients with SIIA during 1999 to 2001 with 204 during 2013 to 2015. Any treatment with epinephrine (before arrival to the ED or in the ED) increased over time (30% vs 49%; P < .001). Prescriptions for epinephrine auto-injector at discharge increased significantly (34% vs 57%; P < .001), whereas documentation of referral to an allergist/immunologist decreased (28% vs 12%; P = .002), and instructions to avoid the offending allergen did not change (23% vs 24%; P = .94). Receipt of at least 3 guideline recommendations increased over time; however, the comparison was not statistically significant (10% vs 16%; P = .15).

CONCLUSION

During the nearly 15-year study interval, we observed increased ED concordance with epinephrine-related guideline recommendations for the management of SIIA. Reasons for the decrease in allergy/immunology referrals merit further study.

The Epidemiology of Anaphylaxis

Anaphylaxis is a dramatic expression of systemic allergy. The lifetime prevalence of anaphylaxis is currently estimated at 0.05-2 % in the USA and ~3 % in Europe. Several population-specific studies have noted a rise in the incidence, particularly in the hospitalizations and ER visits due to anaphylaxis. The variable signs and symptoms that constitute the diagnostic criteria for anaphylaxis, the differences in diagnostic algorithms, and the limitations in the current coding systems have made summarizing epidemiologic data and comparing study results challenging. Nevertheless, across all studies, the most common triggers continue to be medications, food, and venom. Various risk factors for more severe reactions generally include older age, history of asthma, and having more comorbid diseases. Interesting seasonal, geographic, and latitude differences have been observed in anaphylaxis prevalence and incidence rates, suggesting a possible role of vitamin D and sun exposure in modifying anaphylaxis risk. While the incidence and prevalence of anaphylaxis appear to be increasing in certain populations, the overall fatality rate remains relatively low.

Critical view of anaphylaxis epidemiology: open questions and new perspectives

In contrast to the majority of allergic or hypersensitivity conditions, worldwide anaphylaxis epidemiological data remain sparse with low accuracy, which hampers comparable morbidity statistics. Data can differ widely depending on a number of variables. In the current document we reviewed the forms on which anaphylaxis has been defined and classified; and how it can affect epidemiological data. With regards to the methods used to capture morbidity statistics, we observed the impact of the anaphylaxis coding utilizing the World Health Organization's International Classification of Diseases. As an outcome and depending on the anaphylaxis definition, we extracted the cumulative incidence, which may not reflect the real number of new cases. The new ICD-11 anaphylaxis subsection developments and critical view of morbidity statistics data are discussed in order to reach new perspectives on anaphylaxis epidemiology.

Anaphylaxis triggers in a large tertiary care hospital in Qatar: a retrospective study

BACKGROUND

Anaphylaxis is a serious allergic disease that may lead to death if not immediately recognized and treated. Triggers of anaphylaxis including food, drugs, and insect stings can vary widely. The incidence of anaphylaxis seems to be affected by age, sex, atopy, and geographic location. This study aims to examine the common triggers of anaphylaxis in Qatar.

METHODS

A total of 1068 electronic medical records were audited using power chart system: 446 from the medical coding system of anaphylaxis and 622 from the epinephrine auto-injectors (EAIs) dispensed during January 2012-December 2017.

RESULTS

Of 1068 patients, 574 (53.5%) had anaphylaxis; male to female ratio was 1.2, and 300 patients (77.9%) were less than 10 years old. The common triggers were food (n = 316, 55.0%), insect stings (n = 161, 28.0%), and drugs (n = 103, 17.9%). Common anaphylaxis food triggers were nuts (n = 173, 30.1%), eggs (n = 89, 15.5%), and seafood (n = 72, 12.5%), and common anaphylaxis medication triggers were antibiotics (n = 49, 8.5%) and nonsteroidal anti-inflammatory drugs (n = 30, 5.2%). Interestingly, 135 anaphylactic patients (23.5%) were due to black ant stings. The anaphylaxis triggers varied significantly between children and adults. Among children (less than 10 years), three quarters of the events were triggered by food (223, 74.3%) while among adults (20-55 years), insect stings (n = 59, 43.0%) and drugs (n = 44, 32.0%) were dominant.

DISCUSSION

This is the first national study stratifying anaphylaxis triggers among different age groups in Qatar. This study will serve as a guide for clinical practice in allergy clinics in Qatar and will help to assess future trends of anaphylaxis in Qatar.

Anaphylaxis to foods in a population of adolescents: incidence, characteristics and associated risks

BACKGROUND

Information about severe reactions to foods in adolescence is limited.

OBJECTIVE

To describe reactions to foods, including anaphylaxis, with regard to incidence, characteristics and associated risks, among 16-year-olds (adolescents) in a large, population-based birth cohort.

METHODS

Parent-reported questionnaire data from ages 2-3 months, and 1, 2 and 16 years were used (N = 3153). Anaphylaxis at age 16 years was defined per NIAID/FAAN criteria. Immunoglobulin E (IgE) antibodies to 14 common food and inhalant allergens were analysed at ages 4 (n = 2283) and 16 years (n = 2510). Among adolescents with food-related symptoms (FRS) and for whom blood was available (n = 221), 25 additional food allergen extracts or allergen components were analysed. Associations between reactions to foods, and sensitization and allergic multimorbidity were investigated.

RESULTS

In the 12 months prior to the 16-year assessment, 8.5% of adolescents had FRS. This included 0.8% (n = 24) adolescents who were classified as having anaphylaxis, yielding an incidence rate of 761/100 000 person-years. One-third of adolescents accessed health care during anaphylaxis. Allergic multimorbidity in infancy, as well as sensitization to foods and airborne allergens at age 4 years, was associated with an increased risk for FRS in adolescence. Peanuts and tree nuts were the most common culprit foods for anaphylaxis, and fruits and vegetables for non-anaphylactic reactions. Adolescents with anaphylaxis were significantly more likely to be sensitized to storage proteins (Ara h 2, Cor a 9, Cor a 14) and to be polysensitized to foods (P < 0.001 vs. non-anaphylactic reactions).

CONCLUSIONS AND CLINICAL RELEVANCE

The incidence of food-induced anaphylaxis during adolescence in our population-based birth cohort is higher than previously reported. Adolescents with anaphylaxis differ from adolescents with non-anaphylactic FRS with regard to culprit foods and sensitization. Adolescents with previous anaphylaxis are likely to be polysensitized to foods, particularly tree nut and peanut storage proteins, and which warrants consideration at follow-up.

Epidemiology of Food Allergy

Understanding the epidemiology of food allergy is complicated by the difficulty of identifying it on a large scale. The prevalence of food allergy is higher in younger age groups and decreases with age. Allergy to peanut and egg seems to be more common in Northern Europe, the United States, Canada and Australia compared with Southern Europe, Eastern Europe and Asia, whereas shellfish and fish allergies may be more common in Asia. The rate of transient unrecognized food allergy may be high and variable recognition of food allergy may explain some of the differences seen in food allergy prevalence.

Epidemiology of anaphylaxis at a tertiary care center: A report of 730 cases

BACKGROUND

Recent data reveal that the rate of anaphylaxis is increasing and suggest that idiopathic anaphylaxis may account for most of these cases.

OBJECTIVE

To determine the pattern of anaphylaxis at a tertiary care referral center.

METHODS

A retrospective electronic medical record review spanning 12 years (2002-2013) identified patients with anaphylaxis.

RESULTS

Of the 4,777 records reviewed, 730 patients met our anaphylaxis definition. Median age was 34.0 years; 72.7% were adults, 58.6% were female, and 86.8% were white. Median time to evaluation by an allergist was 8.8 months. Foods were the most common cause (29.9%), followed by Hymenoptera venom (24.6%), idiopathic anaphylaxis (13.7%), and medications (13.3%). The most common foods were peanuts (23.9%), tree nuts (21.6%), shellfish (16.1%), and egg and milk (both 10.1%). The most common cause of anaphylaxis in adults was Hymenoptera venom. The most frequent symptoms were urticaria and/or angioedema, reported in 84.7% of cases. Atopy was present in 43.8%. In 15.4% of cases, anaphylaxis was not the chief reason for the office visit.

CONCLUSION

We found food allergy was the most common overall cause of anaphylaxis, with peanut the most frequent food trigger. Idiopathic anaphylaxis was not the most common cause but accounted for 13.7% of all cases. Approximately 1 in 6 cases of anaphylaxis may be missed if a comprehensive evaluation is not performed.

Drug allergies documented in electronic health records of a large healthcare system

BACKGROUND

The prevalence of drug allergies documented in electronic health records (EHRs) of large patient populations is understudied.

OBJECTIVE

We aimed to describe the prevalence of common drug allergies and patient characteristics documented in EHRs of a large healthcare network over the last two decades.

METHODS

Drug allergy data were obtained from EHRs of patients who visited two large tertiary care hospitals in Boston from 1990 to 2013. The prevalence of each drug and drug class was calculated and compared by sex and race/ethnicity. The number of allergies per patient was calculated and the frequency of patients having 1, 2, 3…, or 10+ drug allergies was reported. We also conducted a trend analysis by comparing the proportion of each allergy to the total number of drug allergies over time.

RESULTS

Among 1 766 328 patients, 35.5% of patients had at least one reported drug allergy with an average of 1.95 drug allergies per patient. The most commonly reported drug allergies in this population were to penicillins (12.8%), sulfonamide antibiotics (7.4%), opiates (6.8%), and nonsteroidal anti-inflammatory drugs (NSAIDs) (3.5%). The relative proportion of allergies to angiotensin-converting enzyme (ACE) inhibitors and HMG CoA reductase inhibitors (statins) have more than doubled since early 2000s. Drug allergies were most prevalent among females and white patients except for NSAIDs, ACE inhibitors, and thiazide diuretics, which were more prevalent in black patients.

CONCLUSION

Females and white patients may be more likely to experience a reaction from common medications. An increase in reported allergies to ACE inhibitors and statins is noteworthy.

Incidence of food anaphylaxis in people with food allergy: a systematic review and meta-analysis

BACKGROUND

Food allergy is a common cause of anaphylaxis, but the incidence of anaphylaxis in food allergic people is unknown.

METHODS

We undertook a systematic review and meta-analysis, using the inverse variance method. Two authors selected studies by consensus, independently extracted data and assessed study quality using the Newcastle-Ottawa assessment scale. We searched Medline, Embase, PsychInfo, CINAHL, Web of Science, LILACS and AMED between January 1946 and September 2012 and recent conference abstracts. We included registries, databases or cohort studies which described the number of food anaphylaxis cases in a defined population and time period and applied an assumed population prevalence of food allergy.

RESULTS

We included data from 34 studies. There was high heterogeneity between study results, possibly due to variation in study populations, anaphylaxis definition and data collection methods. In food allergic people, medically coded food anaphylaxis had an incidence rate of 0.14 per 100 person-years (95% CI 0.05, 0.35; range 0.01, 1.28). In sensitivity analysis using different estimated food allergy prevalence, the incidence varied from 0.11 to 0.21 per 100 person-years. At age 0-19, the incidence rate for anaphylaxis in food allergic people was 0.20 (95% CI 0.09, 0.43; range 0.01, 2.55; sensitivity analysis 0.08, 0.39). At age 0-4, an incidence rate of up to 7.00 per 100 person-years has been reported. In food allergic people, hospital admission due to food anaphylaxis had an incidence rate of 0.09 (95% CI 0.01, 0.67; range 0.02, 0.81) per 1000 person-years; 0.20 (95% CI 0.10, 0.43; range 0.04, 2.25) at age 0-19 and 0.50 (0.26, 0.93; range 0.08, 2.82) at age 0-4.

CONCLUSION

In food allergic people, the incidence of food allergic reactions which are coded as anaphylaxis by healthcare systems is low at all ages, but appears to be highest in young children.

Differences in hospital attendance for anaphylaxis between immigrants and non-immigrants: a cohort study

BACKGROUND

The impact of migration on the risk of anaphylaxis remains unknown. We hypothesized that non-Western immigrants have a lower incidence of anaphylaxis compared to Danish-born. We investigated variations in hospital attendance for anaphylaxis between immigrants and Danish-born including time- and age- trends.

METHODS

A register-based, historical prospective cohort design. Refugees or family reunified immigrants (n = 127 250) who, between January 1, 1994 and December 31, 2010, obtained residency permits in Denmark were included and matched in a 1 : 6 ratio on age and sex with Danish-born individuals (n = 740 600). Personal identification numbers were cross-linked to the Danish National Patient Registry identifying all first-time hospital attendances for anaphylaxis from January 1, 1994 and December 31, 2010. Incidence rate ratios were estimated, stratified for sex and region of birth, adjusting for age using a Cox regression model including the influence of duration of residence and age when residence was obtained.

RESULTS

In total 1053 hospital attendances for anaphylaxis were identified: 89 among non-Western immigrants, 9 among Western immigrants and 955 among Danish-born patients. Both male (RR = 0.65; 95%CI: 0.46;0.90) and female (RR = 0.64; 95%CI: 0.48;0.85) non-Western immigrants had a significantly lower risk ratio of hospital attendance for anaphylaxis compared to Danish-born. Compared to Danish-born, non-Western immigrants living in Denmark during the entire follow-up period also showed a decreased risk (RR = 0.65; 95%CI: 0.34;1.25). Compared to Danish-born, non-Western immigrants who obtained residence permission as children had a decreased risk of hospital attendance for anaphylaxis (RR = 0.48; 95%CI: 0.25;0.91).

CONCLUSION

This Danish register-based study using nationwide data revealed fewer hospital attendances for anaphylaxis among non-Western immigrants compared to Danish-born; however this protection was lost over time.

Epidemiology of anaphylaxis

Knowledge about the epidemiology of anaphylaxis is based on data from various sources: clinical practice, large secondary clinical and administrative databases of primary care or hospitalized patients, and recent surveys with representative samples of the general population. As several similar results are often reported in several publications and populations, such findings are highly like to be robust. One such finding is that the incidence and prevalence of anaphylaxis are higher than previously thought. Publications from the last 5 years reveal an incidence of between 50 and 112 episodes per 100 000 person-years; estimated prevalence is 0.3-5.1% depending on the rigour of the definitions used. Figures are higher in children, especially those aged 0-4 years. Publications from various geographical areas based on clinical and administrative data on hospitalized patients suggest that the frequency of admissions due to anaphylaxis has increased (5-7-fold in the last 10-15 years). Other publications point to a geographic gradient in the incidence of anaphylaxis, with higher frequencies recorded in areas with few hours of sunlight. However, these trends could be the result of factors other than a real change in the incidence of anaphylaxis, such as changes in disease coding and in the care provided. Based on data from the records of voluntary declarations of death by physicians and from large national databases, death from anaphylaxis remains very infrequent and stands at 0.35-1.06 deaths per million people per year, with no increases observed in the last 10-15 years. Although anaphylaxis can be fatal, recurrence of anaphylaxis--especially that associated with atopic diseases and hymenoptera stings--affects 26.5-54% of patients.

Anaphylaxis and ethnicity: higher incidence in British South Asians

BACKGROUND

The incidence of anaphylaxis in South Asians (Indian, Pakistani and Bangladeshi ethnicity) is unknown. Birmingham is a British city with a disproportionately large population of South Asians (22.5%) compared with the rest of the UK (4.9%). The main aims of this study were to determine the incidence and severity of anaphylaxis in this population and to investigate the differences between the South Asian and White populations.

METHODS

A retrospective electronic search of emergency department attendances at three hospitals in Birmingham during 2012 was carried out. Wide search terms were used, medical notes were scrutinized, and the World Allergy Organization diagnostic criteria for anaphylaxis were applied. Patients' age, sex, ethnicity and home postal code were collected, reactions were graded by severity, and other relevant details including specialist assessment were extracted. Multivariate analysis was undertaken using 2011 UK census data.

RESULTS

Age-, sex- and ethnicity-standardized incidence rate of anaphylaxis was 34.5 per 100 000 person-years. Multivariate logistic regression which controlled for the confounders of age, sex and level of socioeconomic deprivation showed that incidence was higher in the South Asian population (OR 1.48, P = 0.005). Incidence rate in the South Asian population was 58.3 cases per 100 000 person-years compared to 31.5 in the White population. South Asian children were more likely to present with severe anaphylaxis (OR 5.31, P = 0.002).

CONCLUSIONS

Incidence of anaphylaxis is significantly higher in British South Asians compared to the white population. British South Asian children are at a greater risk of severe anaphylaxis than White children.

Anaphylaxis to insect venom allergens: role of molecular diagnostics

Anaphylaxis due to Hymenoptera stings is one of the most severe consequences of IgE-mediated hypersensitivity reactions. Although allergic reactions to Hymenoptera stings are often considered as a general model for the underlying principles of allergic disease, diagnostic tests are still hampered by a lack of specificity and venom immunotherapy by severe side effects and incomplete protection. In recent years, the knowledge about the molecular composition of Hymenoptera venoms has significantly increased and more and more recombinant venom allergens with advanced characteristics have become available for diagnostic measurement of specific IgE in venom-allergic patients. These recombinant venom allergens offer several promising possibilities for an improved diagnostic algorithm. Reviewed here are the current status, recent developments, and future perspectives of molecular diagnostics of venom allergy. Already to date, it is foreseeable that component-resolution already has now or will in the future have the potential to discriminate between clinically significant and irrelevant sensitization, to increase the specificity and sensitivity of diagnostics, to monitor immunotherapeutic intervention, and to contribute to the understanding of the immunological mechanisms elicited by insect venoms.

Pediatric emergency department visits and hospitalizations due to food-induced anaphylaxis in Illinois

BACKGROUND

Rates of food-induced anaphylaxis among children remain uncertain. In addition, little is known about the demographics of children who have experienced food-induced anaphylaxis resulting in emergency department (ED) visits and/or subsequent hospitalizations.

OBJECTIVES

To evaluate trends in ED visits and hospital admissions due to food-induced anaphylaxis among Illinois children and to identify socioeconomic variation in trend distribution.

METHODS

Illinois hospital discharge data compiled by the Illinois Hospital Association were used to identify ED visits or hospitalizations for food-induced anaphylaxis in Illinois hospitals from 2008-2012. Data for children aged 0 to 19 years who were Illinois residents and received a diagnosis of food-induced anaphylaxis based on International Classification of Diseases, Ninth Revision, Clinical Modification codes (995.60 through 995.69) were included for analysis.

RESULTS

There was a significant increase in the rate of ED visits and hospital admissions due to food-induced anaphylaxis among children in Illinois during the 5-year period, with an annual percent increase of 29.1% from 6.3 ED visits and hospital admissions per 100,000 children in 2008 to 17.2 in 2012 (P < .001). Increases in visit frequency were observed for all study variables, including age, sex, race/ethnicity, insurance type, metropolitan status, hospital type, and allergenic food. Visits were most frequent each year for Asian children and children with private insurance. However, the annual percent increase in visits was most pronounced among Hispanic children (44.3%, P < .001) and children with public insurance (30.2%, P < .001).

CONCLUSION

ED visits and hospital admissions for food-induced anaphylaxis have increased during a 5-year period among children in Illinois, regardless of race/ethnicity and socioeconomic status.

Glucocorticoids and Hospital Length of Stay for Children with Anaphylaxis: A Retrospective Study

OBJECTIVE

To evaluate whether glucocorticoid administration is associated with improved outcomes in children with anaphylaxis.

STUDY DESIGN

We included children from the Pediatric Health Information System database who were diagnosed with anaphylaxis at 35 US children's hospitals between 2009 and 2013. Patients were stratified by disposition from the emergency department (ED), either hospitalized or discharged. We evaluated the association between glucocorticoid administration and prolonged length of stay (LOS), defined as hospital stay ≥ 2 days, and subsequent epinephrine administration among hospitalized children. Among discharged children, we assessed the association between glucocorticoid administration and ED revisits within 3 days. Analyses were adjusted for illness severity using ordering of laboratory tests, medications, oxygen, intravenous fluids, and admission to the intensive care unit.

RESULTS

Among 5203 children hospitalized with anaphylaxis, 424 (8.2%) had prolonged LOS. Glucocorticoid administration was inversely associated with prolonged LOS (aOR, 0.61; 95% CI, 0.41-0.93) and with subsequent epinephrine use (aOR, 0.63; 95% CI, 0.43-0.84) among hospitalized children. Glucocorticoid administration was not associated with the odds of a 3-day revisit (aOR, 1.01; 95% CI, 0.50-2.05) among discharged patients.

CONCLUSION

The use of glucocorticoids was inversely associated with prolonged LOS among children hospitalized with anaphylaxis, but was not associated with 3-day ED revisits among discharged children. These findings support the use of glucocorticoids in children hospitalized with anaphylaxis.

Anaphylaxis cases presenting to primary care paramedics in Quebec

Data on anaphylaxis cases in pre-hospital settings is limited. As part of the Cross Canada Anaphylaxis Registry (C-CARE), we assessed anaphylaxis cases managed by paramedics in Outaouais, Quebec. A software program was developed to prospectively record demographic and clinical characteristics as well as management of cases meeting the definition of the anaphylaxis. Univariate and multivariate logistic regressions were compared to assess factors associated with severity of reactions and epinephrine use. Among 33,788 ambulance calls of which 23,486 required transport, 104 anaphylaxis cases were identified (anaphylaxis rate of 0.31% [95%CI, 0.25%, 0.37%] among all ambulance calls and 0.44% [95%CI, 0.36%, 0.54%] among those requiring transport). The median age was 46.8 years and 41.3% were males. The common triggers included food (32.7% [95%CI, 24.0%, 42.7%]), drugs (24.0% [16.4%, 33.6%]), and venom (17.3% [10.8%, 26.2%]). Among all reactions, 37.5% (95%CI, 28.4%, 47.6%) were severe. Epinephrine was not administered in 35.6% (95%CI, 26.6%, 45.6%) of all cases. Males were more likely to have severe reactions (Odds ratio [OR]: 2.50 [95%CI, 1.03, 6.01]). Venom-induced reactions and severe anaphylaxis were more likely to be managed with epinephrine (OR: 6.9 [95%CI, 1.3, 35.3] and 4.2 [95%CI, 1.5, 12.0], respectively). This is the first prospective study evaluating anaphylaxis managed by paramedics. Anaphylaxis accounts for a substantial proportion of the cases managed by paramedics in Outaouais, Quebec and exceeds prior reports of the proportion of Quebec emergency room visits attributed to anaphylaxis. Although guidelines recommend prompt use of epinephrine for all cases of anaphylaxis, more than a third of cases did not receive epinephrine. It is crucial to develop educational programs targeting paramedics to promote the use of epinephrine in all cases of anaphylaxis regardless of the specific trigger.

Drug-induced anaphylactic reactions in Indian population: A systematic review

BACKGROUND

Epidemiological data on drug-induced anaphylactic reactions are limited in India and are largely depending on studies from developed countries.

AIM

The aim was to analyze the published studies of drug-induced anaphylaxis reported from India in relation with causative drugs and other clinical characteristics.

MATERIALS AND METHODS

The electronic databases were searched for Indian publications from 1998 to 2013 describing anaphylactic reactions. The information was collected for demographics, set up in which anaphylaxis occurred, causative drugs, incubation period, clinical features, associated allergic conditions, past reactions, co-morbid conditions, skin testing, IgE assays, therapeutic intervention and mortality. Reactions were analyzed for severity, causality, and preventability. Data were extracted and summarized by absolute numbers, mean (95% confidence interval [CI]), percentages and odds ratio (OR) (95% CI).

RESULTS

From 3839 retrieved references, 52 references describing 54 reactions were included. The mean age was 35.31 (95% CI: 30.52-40.10) years. Total female patients were 61.11%. Majority reactions were developed in perioperative conditions (53.70%), ward (20.37%) and home (11.11%). The major incriminated groups were antimicrobials (18.52%), nonsteroidal antiinflammatory drugs-(NSAIDs) (12.96%) and neuromuscular blockers (12.96%). Common causative drugs were diclofenac (11.11%), atracurium (7.41%) and β-lactams (5.96%). Cardiovascular (98.15%) and respiratory (81.48%) symptoms dominated the presentation. Skin tests and IgE assays were performed in 37.03% and 18.52% cases, respectively. The fatal cases were associated with complications (OR =5.04; 95% CI: 1.41-17.92), cerebral hypoxic damage (OR =6.80; 95% CI: 2.14-21.58) and preventable reactions (OR =14.33; 95% CI: 2.33-87.97).

CONCLUSION

Antimicrobials, NSAIDs, and neuromuscular blockers are common causative groups. The most fatal cases can be prevented by avoiding allergen drugs.

Immunization with Hypoallergens of shrimp allergen tropomyosin inhibits shrimp tropomyosin specific IgE reactivity

Designer proteins deprived of its IgE-binding reactivity are being sought as a regimen for allergen-specific immunotherapy. Although shrimp tropomyosin (Met e 1) has long been identified as the major shellfish allergen, no immunotherapy is currently available. In this study, we aim at identifying the Met e 1 IgE epitopes for construction of hypoallergens and to determine the IgE inhibitory capacity of the hypoallergens. IgE-binding epitopes were defined by three online computational models, ELISA and dot-blot using sera from shrimp allergy patients. Based on the epitope data, two hypoallergenic derivatives were constructed by site-directed mutagenesis (MEM49) and epitope deletion (MED171). Nine regions on Met e 1 were defined as the major IgE-binding epitopes. Both hypoallergens MEM49 and MED171 showed marked reduction in their in vitro reactivity towards IgE from shrimp allergy patients and Met e 1-sensitized mice, as well as considerable decrease in induction of mast cell degranulation as demonstrated in passive cutaneous anaphylaxis assay. Both hypoallergens were able to induce Met e 1-recognizing IgG antibodies in mice, specifically IgG2a antibodies, that strongly inhibited IgE from shrimp allergy subjects and Met e 1-sensitized mice from binding to Met e 1. These results indicate that the two designer hypoallergenic molecules MEM49 and MED171 exhibit desirable preclinical characteristics, including marked reduction in IgE reactivity and allergenicity, as well as ability to induce blocking IgG antibodies. This approach therefore offers promises for development of immunotherapeutic regimen for shrimp tropomyosin allergy.

International survey of knowledge of food-induced anaphylaxis

BACKGROUND

Studies show that anaphylaxis is under-recognized and epinephrine (adrenaline) is under-used by medical personnel as well as patients and their families. This study assesses the knowledge of food-induced anaphylaxis diagnosis and management across different populations of providers and caregivers and other interested respondents.

METHODS

An online survey embedded in a case discussion of food-induced anaphylaxis was distributed by Medscape to registered members.

RESULTS

A total of 7822 responders who started the activity chose to answer at least some of the questions presented (response rate 39.5%). Over 80% of responders in all groups correctly identified the case of anaphylaxis with prominent skin and respiratory symptoms; however, only 55% correctly recognized the case without skin symptoms as anaphylaxis. Only 23% of responders correctly selected risk factors for anaphylaxis, with physicians significantly more likely to choose the correct answers as compared to allied health, other health professionals, and medical students (p < 0.001). Ninety-five percent selected epinephrine (adrenaline) as the most appropriate treatment for anaphylaxis, and 81% correctly indicated that there are no absolute contraindications for epinephrine (adrenaline) in the setting of anaphylaxis. When presented a case of a child with no documented history of allergies who has symptoms of anaphylaxis, more physicians than any other group chose to administer stock epinephrine (adrenaline) (73% vs. 60%, p < 0.001).

CONCLUSION

Specific knowledge deficits for food-induced anaphylaxis persist across all groups. Further educational efforts should be aimed not only at the medical community but also for the entire caregiver community and general public, to optimize care for food allergic individuals.

Allergists' self-reported adherence to anaphylaxis practice parameters and perceived barriers to care: an American College of Allergy, Asthma, and Immunology member survey

BACKGROUND

Anaphylaxis is life-threatening and requires rapid medical intervention. Knowledge of treatment guidelines and addressing barriers to care are essential for appropriate management.

OBJECTIVE

To investigate allergists' self-reported practices in managing patients at risk for anaphylaxis, specifically in following practice parameters for diagnosis, treatment, and appropriate use of epinephrine, and to identify perceived barriers to care.

METHODS

Online questionnaires were distributed to members of the American College of Allergy, Asthma, and Immunology. The US physicians who self-identified as "allergist/immunologist" were eligible to participate. The first 500 completed questionnaires were analyzed.

RESULTS

Nearly all (≥95%) reported adherence to practice parameters in prescribing an epinephrine auto-injector and instructing patients on its use, taking a detailed allergy history, counseling patients on avoidance measures, and educating patients on the signs and symptoms of anaphylaxis. More than 90% stated they determined the best diagnostic procedures to identify triggers and coordinated laboratory and allergy testing. Adherence to practice parameters was less robust for providing patients with written action plans and in-office anaphylaxis preparedness. Perceived barriers to care included a significant proportion of patients who were uncomfortable using epinephrine auto-injectors and inadequate knowledge of anaphylaxis among referral physicians.

CONCLUSION

Allergists overwhelmingly adhere to practice parameter recommendations for the treatment and management of anaphylaxis, including appropriate use of epinephrine as first-line treatment, educating patients, and testing to diagnose anaphylaxis and identify its triggers. Opportunities for improvement include preparing staff and patients for anaphylactic events, providing written action plans, and improving knowledge of referring physicians.

Anaphylaxis on the other front line: perspectives from the emergency department

Although most cases of anaphylaxis are treated in the emergency department (ED), personnel may not immediately recognize anaphylaxis based on presenting symptoms because it has a wide range of clinical manifestations and variable progression. When symptoms happen to be atypical or mild and when no trigger is identified, the diagnosis of anaphylaxis can be challenging. Underdiagnosis of anaphylaxis can lead to delayed use of appropriate first-line epinephrine in favor of treatments that should be used as adjunctive only. Even when anaphylaxis is recognized, the choice between an epinephrine autoinjector or epinephrine ampule can still present a challenge. Treatment of anaphylaxis in the ED should include a combination of intramuscular epinephrine, supplemental oxygen, and intravenous fluids. If there is an incomplete response to the initial dose of epinephrine, additional doses or other measures may be considered. The most important management consideration is avoiding treatment delays, because symptoms can progress rapidly. Upon discharge from the ED, all patients with anaphylaxis should be given a prescription for at least 2 epinephrine autoinjectors, an initial emergency action plan, education about avoidance of triggers, and a referral to an allergist. A significant limitation of current studies is that clinical outcomes in anaphylaxis associated with established poor rates of diagnosis and use of recommended treatments are unclear; such trials must be conducted as supporting evidence for ED management guidelines for anaphylaxis.

An update on venom allergy

PURPOSE OF REVIEW

Allergic reactions to stinging insects may be unexpected, frightening, and severe. A clear understanding of recent advances in the field facilitates appropriate care of children who experience severe reactions to hymenoptera stings.

RECENT FINDINGS

Recent investigations have underscored the importance of appropriate patient selection for potentially life-saving venom immunotherapy. Venom immunotherapy is effective in preventing future anaphylaxis from hymenoptera stings. Immunotherapy is indicated for patients with a history of anaphylaxis. Children who develop large local swelling or strictly cutaneous systemic reactions generally do not require immunotherapy. Component resolved diagnostic testing has been investigated to clarify the possibility of multiple venom allergies in patients with sensitization to multiple venoms.

SUMMARY

Rapid recognition and treatment of anaphylaxis are critical. Subsequent education about avoiding future stings and attention to emergency preparedness with appropriate prescription of self-injectable epinephrine is important. Referral of patients who have experienced venom-associated anaphylaxis for possible venom immunotherapy can prevent future severe episodes of anaphylaxis resulting from stings.