Multicenter study of repeat epinephrine treatments for food-related anaphylaxis

Preventing food allergy fatalities

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

Evaluation and Management of Food Allergies in the Emergency Department

Food allergies are a common and serious cause of illness, accounting for an increasing number of emergency department visits annually. Although definite diagnosis lays outside of an emergency department visit, the clinical management of the most serious food allergies highlights emergency care. The staple of acute care remains epinephrine in association with antihistamines and steroids. The greatest threat remains undertreatment for this group of disorders and underutilization of epinephrine. Those who have been treated for a food allergy need a follow-up allergist evaluation, guidance of food avoidance, and avoidance of foods with cross-sensitivities as well as ready access to epinephrine.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

DISCUSSION

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

Healthcare Providers' Perception and Practice Toward Anaphylaxis in Children in the Qassim Region of Saudi Arabia

INTRODUCTION

Anaphylaxis is described as a severe allergic reaction, and prompt assistance is required by the patient to avoid any complications. The healthcare provider's knowledge plays an important role in the diagnosis and treatment of these cases. The aim of this study was to evaluate the knowledge among the primary healthcare providers working in the Qassim region of Saudi Arabia regarding the diagnosis and treatment of anaphylaxis.

METHOD

This cross-sectional study was conducted in the four different governments of the Qassim region of Saudi Arabia. The calculated sample size for the study was 119 primary healthcare providers. A self-administered questionnaire was devised to collect data regarding the diagnosis and treatment of anaphylaxis patients.

RESULTS

Thirty-six (28.8%) out of 119 physicians were 25-30 years old, followed by 33 (26.4%) who were more than 40 years old; 53 (42.4%) and 47 (36.7%) had less than five and more than 10 years of experience, respectively. Age and experience were found to be significantly associated with knowledge about the diagnostic criterion (p=0.003 and p=0.000, respectively), while experience was significantly associated with the correct identification of signs and symptoms (p=0.031).

CONCLUSION

Knowledge about the diagnosis and management of anaphylaxis patients among primary healthcare providers was poor. Physicians are required to be educated to increase their level of knowledge to promptly diagnose and treat anaphylaxis cases.

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.

EAACI guidelines: Anaphylaxis (2021 update)

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

Clinical features of anaphylaxis in children

Background: Despite the considerable increase in anaphylaxis frequency, there are limited studies on clinical features of anaphylaxis in children in developing countries. Objective: We aimed to analyze the demographic and clinical features of anaphylaxis in children in Turkey by comparing different age groups and triggers. Methods: Medical records of 147 children, ages 0-18 years, diagnosed with anaphylaxis between 2010 and 2019 were retrospectively analyzed. Results: The mean ± standard deviation age at first anaphylaxis episode was 5.9 ± 5.2 years, with a male predominance (63.9%); 25.2% were infants and 52.4% were < 6 years of age at their first anaphylaxis episode; 78.2% were atopic, with the highest frequency in children with food-induced anaphylaxis (FIA). The home (51.7%) was the most frequent setting. The overall leading cause of anaphylaxis was food (44.2%), which was more frequent at < 6 years of age, followed by drugs (28.6%) and bee venom (22.4%), both were more frequent among older children (>6 years). The patients with venom allergy had the highest rate of rapid onset of symptoms (p < 0.001). Gastrointestinal symptoms were observed significantly more in infants (48.6%) and in children with FIA (38.5%); cardiovascular symptoms were more frequently observed in children > 6 years of age (48.6%) and in children with drug-induced anaphylaxis (64.3%). Although recurrent anaphylaxis was reported for 23.1% of the patients, it was highest in the patients with FIA (35.9%). Overall, only 47.6% of the patients received epinephrine in the emergency department (ED) and 27.3% were referred to an allergy specialist, with the patients with FIA having the lowest rate for both, 32.3% and 10.8%, respectively. Children with drug-induced anaphylaxis had the highest rate of severe anaphylaxis (57.1%). Conclusion: There is a need to improve anaphylaxis recognition and management in all children regardless of age and trigger. Inadequate treatment was most evident in infants and patients with FIA.

Evaluation and Management of Food Allergies in the Emergency Department

Food allergies are a common and serious cause of illness, accounting for an increasing number of emergency department visits annually. Although definite diagnosis lays outside of an emergency department visit, the clinical management of the most serious food allergies highlights emergency care. The staple of acute care remains epinephrine in association with antihistamines and steroids. The greatest threat remains undertreatment for this group of disorders and underutilization of epinephrine. Those who have been treated for a food allergy need a follow-up allergist evaluation, guidance of food avoidance, and avoidance of foods with cross-sensitivities as well as ready access to epinephrine.

Emergency medicine updates: Anaphylaxis

INTRODUCTION

Anaphylaxis is a potentially deadly condition that requires emergent therapy. While frequently treated in the emergency department (ED), recent evidence updates may improve the diagnosis and management of this condition.

OBJECTIVE

This paper evaluates key evidence-based updates concerning the diagnosis and management of anaphylaxis for the emergency clinician.

DISCUSSION

The presentation of anaphylaxis can vary. Current diagnostic criteria can be helpful when evaluating patients for anaphylaxis, though multiple criteria exist. While the most common causes of anaphylaxis include medications, insect venom, and foods, recent literature has identified an IgE antibody response to mammalian galactose alpha-1,3-galactose, known as alpha-gal anaphylaxis. Epinephrine is the first-line therapy and is given in doses of 0.01 mg/kg (up to 0.5 mg in adults) intramuscularly (IM) in the anterolateral thigh. Intravenous (IV) epinephrine administration is recommended in patients refractory to IM epinephrine and IV fluids, or those with cardiovascular collapse. Antihistamines and glucocorticoids should not delay administration of epinephrine and do not demonstrate a significant reduction in risk of biphasic reactions. Biphasic reactions may affect 1-7% of patients with anaphylaxis. Risk factors for biphasic reaction include severe initial presentation and repeated doses of epinephrine. Disposition of patients with anaphylaxis requires consideration of several factors.

CONCLUSIONS

Emergency clinicians must be aware of current updates in the evaluation and management of this disease.

European Resuscitation Council Guidelines 2021: First aid

The European Resuscitation Council has produced these first aid guidelines, which are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. The topics include the first aid management of emergency medicine and trauma. For medical emergencies the following content is covered: recovery position, optimal positioning for shock, bronchodilator administration for asthma, recognition of stroke, early aspirin for chest pain, second dose of adrenaline for anaphylaxis, management of hypoglycaemia, oral rehydration solutions for treating exertion-related dehydration, management of heat stroke by cooling, supplemental oxygen in acute stroke, and presyncope. For trauma related emergencies the following topics are covered: control of life-threatening bleeding, management of open chest wounds, cervical spine motion restriction and stabilisation, recognition of concussion, cooling of thermal burns, dental avulsion, compression wrap for closed extremity joint injuries, straightening an angulated fracture, and eye injury from chemical exposure.

Community Use of Epinephrine for the Treatment of Anaphylaxis: A Review and Meta-Analysis

BACKGROUND

Community use of epinephrine for the treatment of anaphylaxis is low. Knowledge of rates of epinephrine use in the pre-hospital setting along with identification of barriers to its use will contribute to the development of policies and guidelines.

OBJECTIVES

A search was conducted on PubMed and Embase in April 2020. Our systematic review focused on 4 domains: (1) epinephrine use in the pre-hospital setting; (2) barriers to epinephrine use in the pre-hospital setting; (3) cost evaluation and cost-effectiveness of epinephrine use; and (4) programs and strategies to improve epinephrine use during anaphylaxis.

METHODS

Two meta-analyses with logit transformation were conducted to: (1) calculate the pooled estimate of the rate of epinephrine use in the pre-hospital setting among cases of anaphylaxis and (2) calculate the pooled estimate of the rate of biphasic reactions among all cases of anaphylaxis.

RESULTS

Epinephrine use in the pre-hospital setting was significantly higher for children compared with adults (20.98% [95% confidence interval (CI): 16.38%, 26.46%] vs 7.17% [95% CI: 2.71%, 17.63%], respectively, P = .0027). The pooled estimate of biphasic reactions among all anaphylaxis cases was 3.92% (95% CI: 2.88%, 5.32%). Our main findings indicate that pre-hospital use of epinephrine in anaphylaxis remains suboptimal. Major barriers to the use of epinephrine were identified as low prescription rates of epinephrine autoinjectors and lack of stock epinephrine in schools, which was determined to be cost-effective. Finally, in reviewing programs and strategies, numerous studies have engineered effective methods to promote adequate and timely use of epinephrine.

CONCLUSION

The main findings of our study demonstrated that across the globe, prompt epinephrine use in cases of anaphylaxis remains suboptimal. For practical recommendations, we would suggest considering stock epinephrine in schools and food courts to increase the use of epinephrine in the community. We recommend use of pamphlets in public areas (ie, malls, food courts, etc.) to assist in recognizing anaphylaxis and after that with prompt epinephrine administration, to avoid the rare risk of fatality in anaphylaxis cases.

What the COVID-19 Pandemic Can Teach Us About Resource Stewardship and Quality in Health Care

The coronavirus disease 2019 pandemic has forever changed how we view health care service delivery. Although there are undoubtedly some unintended consequences that will result from current health care service reallocation, it provides a unique opportunity to consider how to deliver quality care currently, and after the pandemic. In the context of lessons learned, moving forward some of what was previously routine could remain reserved for more exceptional circumstances. To determine what is "routine," what is "essential," and what is "exceptional," it is necessary to view medical decisions within the paradigm of high-quality care. The Institute for Healthcare Improvement definition of the dimensions of quality is based on whether the care is safe, effective, patient-centered, timely, efficient, and equitable. This type of stewardship has been applied to many interventions already deemed unnecessary by organizations such as the Choosing Wisely initiative, but the coronavirus disease 2019 pandemic provides a lens from which to consider other aspects of care. The following will provide examples from Allergy/Immunology that outline how we can reconsider what quality means in the post-coronavirus disease health care system.

Second Dose of Epinephrine for Anaphylaxis in the First Aid Setting: A Scoping Review

Anaphylaxis is a life-threatening hypersensitivity reaction where rapid, early administration of epinephrine (adrenaline) can be lifesaving in the first aid setting. There are instances where a single dose of epinephrine does not relieve symptoms and a second dose may be required to further mitigate symptoms and preserve life. We performed a scoping review as part of an update to a previously conducted International Liaison Committee on Resuscitation First Aid Task Force (ILCOR) review. PubMed and Embase were searched using the strategy from the 2015 ILCOR review (dates January 1, 2015 to October 22, 2019) and a review of the grey literature (all dates up to November 18, 2019) was performed to identify data on the requirement, use, and effectiveness of a second dose of epinephrine. Each search was rerun on June 26, 2020. We included all human studies of adults and children with an English abstract. Critical outcomes included resolution of symptoms, adverse effects, and complications of second dosing of epinephrine in the treatment of acute anaphylaxis. Included studies are presented descriptively. Our updated search identified 909 potential sources, 890 from the published literature and 19 from the grey literature. After full text review, two studies met our eligibility criteria (Campbell et al. and Akari et al.). For the outcome of resolution of symptoms, both studies found that two or more doses of epinephrine were required in 8% of 582 patients and 28% of 18 patients, respectively, with anaphylaxis requiring treatment with epinephrine. The other a priori outcomes were not reported. This scoping review identified limited evidence regarding the use of a second dose of epinephrine for anaphylaxis in the first aid setting, however, due to the potential benefit, it is reasonable to administer a second dose when symptoms of severe anaphylaxis fail to resolve following an initial dose. Given the potential mortality associated with anaphylaxis, further research is needed to better identify individuals who may benefit from a second dose of epinephrine.

Novel Approaches to Food Allergy Management During COVID-19 Inspire Long-Term Change

The SARS-CoV2 pandemic has prompted a re-evaluation of our current practice of medicine. The seemingly abrupt worldwide spread of this disease resulted in immediate changes and a reduction in many allergy-focussed services and procedures. The reality of the long-term circulation of this virus in our communities requires us to evolve as a specialty. In this article, we outline current and future challenges in the management of food allergy in light of coronavirus disease 2019 (COVID-19). We focus on infant food allergy prevention, management of anaphylaxis, accurate diagnosis with oral food challenges, and active management of food allergy with oral immunotherapy. This article identifies the challenges of conflicting guidelines, shortcomings of acute management approaches, and inherent system deficiencies. We offer perspectives and strategies that can be implemented now, including an evaluation of virtual care and telemedicine for the management of food allergy. The use of a shared decision-making model results in novel approaches that can benefit our patients and our specialty for years to come. COVID-19 has forced us to re-evaluate our current way of thinking about food allergy management to better treat our patients.

Shared decision-making in the care of a patient with food allergy

OBJECTIVE

Shared decision-making is a patient-centered approach that involves a mutual discussion about management or treatment options, which account for the patient's underlying values and preferences for therapy. Little is known about the role of shared decision-making in the care of patients with food allergy.

DATA SOURCES

A narrative review of the shared decision-making and food allergy outcomes literature in the past 20 years was performed.

RESULTS

In shared decision-making, care must be taken to help clarify the patient's values regarding their care options, but not instill the clinician's values or preferences into that choice. It is essential to understand the mutual roles of the clinician in the process of providing evidence-based options for care, advocating for treatments that are aligned with their goals and preferences, and allowing patients to make fully informed decisions within this paradigm. Decision support tools such as decision aids can assist patients in the values clarification process, particularly in which preference-sensitive care exists, in which options hold significant tradeoffs and varying outcomes, and the decision is reflective of personal values and preferences. There are multiple potential preference-sensitive care scenarios in food allergy in which shared decision-making could be optimized, including the development of decision aids. These areas include early allergenic solid introduction, preemptive epinephrine use in which there is allergen exposure but no symptoms, automatic activation of EMS after using epinephrine, and choices of food allergy treatment. Only one decision aid in food allergy exists.

CONCLUSION

Shared decision-making is an approach that could greatly enhance food allergy care and improve patient-reported outcomes.

Are Children with a History of Asthma More Likely to Have Severe Anaphylactic Reactions? A Retrospective Cohort Study

OBJECTIVE

To assess whether a history of asthma was associated with anaphylaxis severity in children hospitalized for anaphylaxis.

STUDY DESIGN

Retrospective cohort study of children ≤21 years old hospitalized for anaphylaxis from 2009 to 2016. The primary outcome was severe anaphylactic reactions defined by examination findings (stridor, respiratory distress, or hypotension) or administered therapies (≥2 dose of intramuscular epinephrine, continuous albuterol, vasopressors, or positive pressure ventilation). Multivariable analyses were used to assess whether a history of asthma was associated with severe anaphylactic reactions, adjusting for patient age, allergen, and history of atopic dermatitis or anaphylaxis.

RESULTS

Among 603 children hospitalized for anaphylaxis, 231 (38.3%) had a history of asthma. Children with a history of asthma were older (median age, 6.6 years [IQR, 3.6-12.1] vs 4.0 years [IQR, 1.6-9.3]), more likely to have a history of anaphylaxis (38.1% vs 18.0%), and have food as the inciting allergen (68.0% vs 52.2%). Children with a history of asthma were not more likely to have severe anaphylactic reactions (OR, 0.97; 95% CI, 0.67-1.39).

CONCLUSIONS

Children hospitalized for anaphylaxis with a history of asthma were not more likely to have severe anaphylactic reactions compared with children without asthma. This study supports managing children with anaphylaxis based on the severity of symptomatology, and, if validated, clinicians should not consider asthma comorbidity as a stand-alone criterion for hospitalization.

Characteristics and Treatment of Anaphylaxis in Children Visiting a Pediatric Emergency Department in Korea

Anaphylaxis is a serious life-threatening allergic disease in children. This study is aimed at determining the characteristics of pediatric patients who experienced anaphylaxis along with treatments administered in order to determine the usefulness of tryptase level assessment as a marker of anaphylaxis in Korean children. A total of 107 patients who were diagnosed with anaphylaxis in a single pediatric emergency center over a 3-year period were included in the study. Patient clinical characteristics, symptoms, signs, allergy history, trigger factors, treatments, and laboratory findings, including serum tryptase levels, were included in the analysis. Food allergies (39.3%) were the most commonly reported patient allergic history, and 58 patients (54.2%) were triggered by food. Among this group, nuts and milk exposure were the most common, affecting 15 patients (25.9%). History of anaphylaxis and asthma were more common in severe anaphylaxis compared to mild or moderate anaphylaxis cases. Epinephrine intramuscular injection was administrated to 76 patients (71.0%), and a self-injectable epinephrine was prescribed to 18 patients (16.8%). The median tryptase level was 4.80 ng/mL (range: 2.70-10.40) which was lower than the 11.4 ng/mL value commonly documented for standard evaluation in adults with anaphylaxis. The most common cause of pediatric anaphylaxis was food including nuts and milk. The rate of epinephrine injection was relatively high in our pediatric emergency department. The median tryptase level associated with anaphylaxis reactions in children was lower than 11.4 ng/mL. Further studies are needed to help improve diagnostic times and treatment accuracy in pediatric patients who develop anaphylaxis.

Changes in Emergency Department Concordance with Guidelines for the Management of Food-Induced Anaphylaxis: 1999-2001 versus 2013-2015

BACKGROUND

Awareness about food allergy and food-induced anaphylaxis (FIA) has increased dramatically over the past decade. It remains unclear, however, whether concordance with guidelines for FIA management has improved over time.

OBJECTIVE

Our objective was to describe changes in emergency department (ED) concordance with guidelines for FIA management.

METHODS

We analyzed data from 2 multicenter retrospective studies of patients with food-related acute allergic reactions seen in 1 of 17 EDs during 2 time periods: 1999 to 2001 and 2013 to 2015. Visits were identified similarly across years-for example, using International Classification of Diseases, Ninth Revision, Clinical Modification codes 693.1, 995.60, 995.61-995.69, 995.0, and 995.3. Anaphylaxis was defined as an acute allergic reaction with involvement of 2+ organ systems or hypotension. We compared concordance between time periods for 4 guideline recommendations: (1) treatment with epinephrine, (2) discharge prescription for an epinephrine autoinjector (EAI), (3) referral to an allergist/immunologist, and (4) instructions to avoid offending allergen.

RESULTS

We compared 290 patients with FIA during 1999 to 2001 and 459 during 2013 to 2015. Any treatment with epinephrine (pre-ED or in the ED) for patients with FIA increased over time (38% vs 56%; P < .001). Prescriptions for EAI at discharge (24% vs 54%; P < .001) and documentation for referral to an allergist/immunologist (14% vs 24%; P = .001) approximately doubled, whereas instructions to avoid the offending allergen did not change significantly (37% vs 43%; P = .08). Receipt of 3+ guideline recommendations remained low but almost quadrupled over the study interval (6% vs 23%; P < .001).

CONCLUSIONS

Over the nearly 15-year study interval, we observed clinically and statistically significant increases in ED concordance with epinephrine-related guidelines for FIA. Management gaps remain and interventions to standardize care still appear warranted.

Utilization of high-fidelity simulation for medical student and resident education of allergic-immunologic emergencies

BACKGROUND

The advantages of clinical simulation used in medical education include the acquisition of clinical skills in a controlled setting, promoting a multidisciplinary approach to patient care, and a high degree of learner satisfaction.

OBJECTIVE

We aimed to identify knowledge gaps among Internal Medicine residents and students in the diagnosis and treatment of anaphylaxis and angiotensin-converting enzyme (ACE)-inhibitor-induced angioedema through their participation in a simulation course.

METHODS

We conducted a cohort study involving clinical simulations with a high-fidelity, patient-simulator. The cases (antibiotic-induced anaphylaxis and ACE-inhibitor-induced angioedema) were standardized and algorithmic. Participants completed a pre- and post- simulation knowledge assessment and course evaluation. A follow-up knowledge survey was sent out 6 to 12 months after the course completion.

RESULTS

Twelve groups comprising 45 medical students and residents completed the anaphylaxis course. All groups diagnosed anaphylaxis after more than 2-organ-system involvement had manifested, and half of the groups made the diagnosis after the patient-simulator was in anaphylactic shock. Half gave an incorrect dose of epinephrine, and most of the participants were inexperienced in epinephrine auto-injector (EAI) administration. Eight groups comprising 27 participants completed the ACE-inhibitor-angioedema course. Six of the groups correctly diagnosed the patient-simulator, but multiple incorrect treatments were given, and only 1 group successfully intubated the patient-simulator. Knowledge improved immediately after the simulation, and knowledge specific to EAI treatment seemed to be retained long-term. All participants agreed that the simulation was practical to their education.

CONCLUSION

Clinical simulation improves knowledge on the diagnosis and treatment of anaphylaxis and ACE-inhibitor-induced angioedema. We advocate that clinical simulation be incorporated at institutions with appropriate capabilities.

Identification of children with anaphylaxis at low risk of receiving acute inpatient therapies

OBJECTIVE

Opportunity exists to reduce unnecessary hospitalizations for children with anaphylaxis given wide variation in admission rates across U.S. emergency departments (EDs). We sought to identify children hospitalized with anaphylaxis at low risk of receiving epinephrine and other acute inpatient therapies, as these patients may be candidates for ED discharge rather than inpatient hospitalization.

METHODS

We conducted a single-center retrospective cohort study of children 1-21 years of age hospitalized with anaphylaxis from 2009 to 2016. Acute inpatient therapies included intramuscular (IM) or racemic epinephrine, bronchodilators, fluid boluses, vasopressors, non-invasive ventilation, or intubation. We derived age-specific (pre-verbal [<36 months] vs. verbal [≥ 36 months]) prediction rules using recursive partitioning to identify children at low risk of receiving acute inpatient therapies.

RESULTS

During the study period 665 children were hospitalized for anaphylaxis, of whom 108 (16.2%) received acute inpatient therapies. The prediction rule for patients < 36 months (no wheezing, no cardiac involvement [hypotension or wide pulse pressure]) had a sensitivity of 90.5% (CI 69.6-98.8%) and a negative predictive value of 98.3% (CI 94.1-99.8%) for identifying children at low risk of receipt of acute inpatient therapies during hospitalization. For children ≥ 36 months, the prediction rule (no wheezing, no cardiac involvement, presence of gastrointestinal symptoms) had a sensitivity of 90.8% (CI 82.7-96.0%) and a negative predictive value of 92.4% (CI 85.6-96.7%).

CONCLUSIONS

We derived age specific prediction rules for children hospitalized with anaphylaxis at low risk of receiving epinephrine and other acute inpatient therapies. These children may be candidates for ED discharge rather than inpatient hospitalization.

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.

An economic evaluation of immediate vs non-immediate activation of emergency medical services after epinephrine use for peanut-induced anaphylaxis

BACKGROUND

Layperson food allergy management plans commonly stipulate that if epinephrine is used to immediately call 911 and seek care in the nearest medical facility for observation.

OBJECTIVE

To evaluate the cost-effectiveness of this strategy, vs a watchful waiting approach before activating emergency medical services (EMS).

METHODS

We performed a cost-effectiveness analysis using Markov modeling simulated over a 20-year horizon comparing activating EMS immediately after epinephrine use for allergic reactions to peanut vs a "wait and see" approach in which EMS was only activated if symptoms of the reaction did not promptly resolve after treatment. The base-case model assumed a 10-fold increased fatality risk with delayed EMS activation.

RESULTS

The fatality risk associated with early EMS use was minimal, with a per-patient fatality rate over a 20-year horizon of 1.2 × 10^-6, vs 1.9 × 10^-6 for a wait and see approach. The incremental cost per life-year saved was $142,943,447 for early EMS vs wait and see, with the cost per death prevented reaching $1,349,335,651 as the simulation concluded. Cost of early EMS activation rose to $321,625,534 per life-year saved ($3,035,454,848 per death prevented) if a 5-fold increase in fatality risk was assumed, and was $12,997,173 per life-year saved ($122,689,936 per death prevented) if a 100-fold increase in fatality risk was assumed.

CONCLUSION

Medical observation of a treated and promptly resolved peanut allergic reaction has minimal benefit and excessive costs. Immediately activating EMS after using epinephrine for a peanut allergic reaction in this context is not cost-effective.

Risk factors for multiple epinephrine doses in food-triggered anaphylaxis in children

BACKGROUND

Food-related anaphylactic reactions may require treatment with more than 1 dose of epinephrine. Current guidelines advise patients at risk of anaphylaxis to carry 2 epinephrine autoinjectors.

OBJECTIVE

The objective of this study was to determine risk factors of multiple-dose epinephrine treatment in pediatric food-related anaphylaxis.

METHODS

Parents of children with physician-confirmed diagnosis of food allergy were administered a standardized questionnaire at the time of their clinic visit. These patients were then followed-up prospectively by phone.

RESULTS

Six hundred forty-two subjects had allergic reactions. Twenty-six percent of patients reported at least 1 reaction treated with epinephrine, for a total of 221 reactions. Among reactions treated with epinephrine, 24 reactions (11%) received 2 or more doses of epinephrine. The most common triggers were milk (30%) and peanut (18%). Milk-triggered allergic reactions (odds ratio [OR] 3.2; 95% confidence interval [CI] 1.2-8.4) and treatment with oxygen (OR 5.0, 95% CI 2.0-12.4) were significant risk factors for requiring multiple doses of epinephrine to treat an allergic reaction.

CONCLUSION

This study demonstrates that treatment of anaphylaxis may require more than 1 epinephrine injection. Reactions triggered by milk or requiring treatment with oxygen are at higher risk for needing more than 1 dose of epinephrine. Families of food-allergic children should be counseled on the importance of carrying 2 epinephrine auto-injectors.

Guidelines for Bystander First Aid 2016

Cardiac life support is a form of first aid for cardiac emergencies. However, research and evidence in this field is lacking compared with other forms of first aid. Having identified the common emergencies that are encountered in the hospital, based on the available evidence, we have put together what could be an evidence-based approach to the first aid management of some of these common emergencies, viz. breathlessness, chest pain, allergies, stroke, heat injury, poisoning, unconsciousness, seizures, and trauma situations such as bleeding, wounds, contusions, head injury, burns and fractures. Educating the public is the key to developing a first responder bystander. These guidelines could become the basis for training of the public.

Environmental exposure to peanut and the risk of an allergic reaction

OBJECTIVE

To review the evidence of the risk of environmental exposure to peanut to a peanut allergic individual.

DATA SOURCES AND STUDY SELECTION

A narrative review was performed using a PubMed search of relevant articles involving peanut environmental distribution, environmental peanut abatement, and public policy regarding peanut restriction.

RESULTS

Data from 4 studies have shown that peanut butter vapors and smeared peanut butter on skin do not cause systemic reactions, that peanut can be abated from hands and surfaces using appropriate cleaning agents, and that shelled peanut dust does not become airborne. Studies have recently confirmed dose of 1.5 mg of peanut protein would be generally tolerated by approximately 95% of the peanut-allergic population based on objective symptoms in challenge-based studies, affirming earlier research. Restrictive policies that focus on bans (or restricted presence in certain areas) of peanuts or peanut-containing products in environments such as schools or on commercial aircraft are not backed by evidence that such measures work, which may raise an uncomfortable clash between accommodations that lack any medical evidence of necessity and a desire to provide measures that comfort our patients.

CONCLUSION

There is little risk posed from non-oral exposure to peanut in the environment, from casual contact, proximity, or inhalation. If 5% of the population may tolerate a threshold of approximately 1.5 mg of peanut protein, this may help liberate behavior and situational-decision making regarding the necessity of certain avoidances and restrictions. Continued work is needed to dispel myths about the mechanisms of how peanut may induce an allergic reaction.

Downstream consequences of diagnostic error in pediatric anaphylaxis

Background

Pediatric anaphylaxis is commonly misdiagnosed in the Emergency Department (ED). We aimed to determine the impact of inaccurate diagnosis on the management and follow-up of pediatric anaphylaxis presenting to the ED.

Methods

Retrospective chart review of ED management of children aged 0–18 years with allergic presentations to three EDs in Melbourne, Australia in 2014. Cases were included if an ED diagnosis of anaphylaxis was recorded, or the presentation met international consensus criteria for anaphylaxis.

Results

Of the 60,143 pediatric ED presentations during the study period, 1551 allergy-related presentations were identified and reviewed. 187 met consensus criteria for anaphylaxis, and another 24 were diagnosed with anaphylaxis without meeting criteria. Of the 211 presentations, 105 cases were given an ED diagnosis of anaphylaxis and 106 cases were given an alternative diagnosis in ED.

Those diagnosed with anaphylaxis were more likely to receive epinephrine [85.7% vs 31.1% (OR = 13.27, 95% CI: 6.09–26.3)], to be observed for the recommended four hours [56.2% vs 29.2% (OR = 3.10, 95% CI 1.76–5.48, p < 0.001)], to have an epinephrine autoinjector available on discharge [81.9% vs 35.8% (OR = 4.12, 95% CI 2.07–8.22, p < 0.001)] and to be referred to an allergist [35.2% vs 16.0% (OR = 2.85, 95% CI 1.48–5.49, p < 0.01)]. Provision of anaphylaxis action plans and allergen avoidance advice was poorly documented for all patients.

Conclusion

Accurate diagnosis of anaphylaxis in ED has a significant impact on observation times, prescription of epinephrine autoinjectors and referral to an allergist. These factors are key to reducing mortality and the significant morbidity that results from childhood anaphylaxis.

Electronic supplementary material

The online version of this article (10.1186/s12887-018-1024-z) contains supplementary material, which is available to authorized users.

Are Registration of Disease Codes for Adult Anaphylaxis Accurate in the Emergency Department?

Purpose

There has been active research on anaphylaxis, but many study subjects are limited to patients registered with anaphylaxis codes. However, anaphylaxis codes tend to be underused. The aim of this study was to investigate the accuracy of anaphylaxis code registration and the clinical characteristics of accurate and inaccurate anaphylaxis registration in anaphylactic patients.

Methods

This retrospective study evaluated the medical records of adult patients who visited the university hospital emergency department between 2012 and 2016. The study subjects were divided into the groups with accurate and inaccurate anaphylaxis codes registered under anaphylaxis and other allergy-related codes and symptom-related codes, respectively.

Results

Among 211,486 patients, 618 (0.29%) had anaphylaxis. Of these, 161 and 457 were assigned to the accurate and inaccurate coding groups, respectively. The average age, transportation to the emergency department, past anaphylaxis history, cancer history, and the cause of anaphylaxis differed between the 2 groups. Cutaneous symptom manifested more frequently in the inaccurate coding group, while cardiovascular and neurologic symptoms were more frequently observed in the accurate group. Severe symptoms and non-alert consciousness were more common in the accurate group. Oxygen supply, intubation, and epinephrine were more commonly used as treatments for anaphylaxis in the accurate group. Anaphylactic patients with cardiovascular symptoms, severe symptoms, and epinephrine use were more likely to be accurately registered with anaphylaxis disease codes.

Conclusions

In case of anaphylaxis, more patients were registered inaccurately under other allergy-related codes and symptom-related codes rather than accurately under anaphylaxis disease codes. Cardiovascular symptoms, severe symptoms, and epinephrine treatment were factors associated with accurate registration with anaphylaxis disease codes in patients with anaphylaxis.

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.

Children Covered by Medicaid/State Children's Health Insurance Program More Likely to Use Emergency Departments for Food Allergies

BACKGROUND

Food allergies (FAs) occur in 4% to 8% of children in the United States, and emergency department (ED) visits account for up to 20% of their costs. In 2010, the National Institute of Allergy and Infectious Diseases established diagnostic criteria and management practices for FAs, and recognition and treatment of FAs for pediatric ED practitioners has been described.

OBJECTIVE

This study identified trends and factors related to ED visits for pediatric FAs in the United States from 2001 to 2010. It was hypothesized that FAs increased and that differences existed in ED utilization based on age, insurance status, and geography. Low concordance with treatment guidelines for FAs was expected.

METHODS

Multivariate logistic regression, using National Hospital Ambulatory Medical Care Survey data, estimated factors associated with ED visits and treatment of FAs and nonspecific allergic reactions. Trends and treatment patters used weighted frequencies to account for the complex 4-stage probability survey design.

RESULTS

An estimated 239,303 (95% confidence interval [CI], 180,322-298,284) children visited the ED for FAs, demonstrating a significant rate increase during the period (53.08, P < 0.001). Logistic regression showed that the odds of ED visits for FAs were significantly associated with Medicaid/State Children's Health Insurance Program insurance (OR, 1.65 [95% CI, 1.01-2.69], P = 0.04), adolescents (OR, 1.92 [95% CI, 1.10-3.35], P = 0.02), and boys (OR, 1.55 [95% CI, 1.03-2.35], P = 0.04). Treatment with epinephrine for anaphylaxis diagnoses occurred in 57.4% of visits (95% CI, 42.3%-66.8%).

CONCLUSIONS

Medicaid/State Children's Health Insurance Program-insured pediatric patients had higher odds of visiting ED for recognized FAs and nonspecific allergic reactions and higher odds of receiving epinephrine than privately insured children.

Inaccurate diagnosis of paediatric anaphylaxis in three Australian Emergency Departments

AIM

To determine the accuracy of emergency department (ED) paediatric anaphylaxis diagnosis, and to identify factors associated with misdiagnosis.

METHODS

Retrospective chart review of children aged 0-18 years with allergic presentations to three Victorian EDs in 2014. Cases were included if an ED diagnosis of anaphylaxis was recorded, or the presentation met international consensus criteria for anaphylaxis.

RESULTS

Of the 60 143 paediatric ED presentations during the study period, 1551 allergy-related presentations were identified and reviewed. One hundred and eighty-seven met consensus criteria for anaphylaxis, and another 24 were diagnosed with anaphylaxis without meeting criteria. Of the 211 presentations, 105 cases were given an ED diagnosis of anaphylaxis and 106 cases were given an alternative diagnosis in ED. ED assessment had a sensitivity of 43.2% (95% confidence interval (CI) 36.1-50.7%) and specificity of 97.9% (95% CI 96.9-98.7%) for anaphylaxis. Multiple logistic regression demonstrated that an ED anaphylaxis diagnosis was associated with previous anaphylaxis (odds ratio (OR) 3.20; 95% CI 1.52-6.75), arrival by ambulance (OR 2.80; 95% CI 1.36-5.74), a high-acuity triage category (OR 4.51; 95% CI 2.20-9.25) and presentation to a tertiary hospital (OR 2.86; 95% CI 1.44-5.67). ED diagnosis of anaphylaxis was less likely in those with resolution of symptoms and signs in at least one organ system prior to arrival (OR 0.27; 95% CI 0.12-0.62).

CONCLUSION

In children with allergic presentations, ED assessment has a low sensitivity but high specificity for anaphylaxis. Attention to resolved pre-hospital symptoms and awareness of diagnostic criteria are important considerations for accurate ED diagnosis of anaphylaxis.

Update on the usage and safety of epinephrine auto-injectors, 2017

Anaphylaxis is a serious, potentially fatal allergic reaction. Guidelines recommend prompt intramuscular injections of epinephrine as the first-line therapy for anaphylaxis. Delayed epinephrine treatment may cause undesirable clinical outcomes, including death. In the community, epinephrine auto-injectors (EAIs) are commonly used to treat anaphylaxis. This literature review examines several recent concerns regarding the safety of EAIs that may prevent the timely administration of epinephrine. Reports of cardiovascular complications are linked with epinephrine administration, although recent studies suggest that these events are much more commonly associated with intravenous epinephrine rather than with EAIs. Recent studies have also highlighted accidental injections of EAIs in patients’ or caregivers’ fingers and lacerations associated with the use of EAI in children. However, the data suggest that both accidental injections and lacerations are rare and require limited medical intervention. In addition, patients may receive conflicting information on the safety and efficacy of using expired EAIs. Overall, it is believed that the benefits of using EAIs far outweigh the potential risks of not administering an EAI. Although legitimate safety concerns are associated with EAIs, adverse events are rare. Continued training of medical providers, caregivers, and patients may be beneficial to address these concerns and reduce EAI-associated injuries while ensuring that patients receive necessary medical care.

Conducting an Oral Food Challenge to Peanut in an Infant

Results from the Learning Early About Peanut trial and its follow-up study suggest that early peanut introduction in the diets of high-risk infants may prevent the development of peanut allergy. Allergy organizations around the world released a unified statement, the Consensus Communication on Early Peanut Introduction and the Prevention of Peanut Allergy in High Risk Infants, in response to results from the Learning Early About Peanut trial, which recommends early introduction of peanut into the diet of those children at greatest risk of development of peanut allergy. As a result, it is expected that practicing allergists will experience an increased demand to perform an oral food challenge (OFC) in infants. Allergists often perform OFCs; however, conducting an OFC in an infant creates unique circumstances that have not been considered in previously published OFC guideline documents. The purpose of this workgroup report is to provide guidance to practitioners regarding the proper approach for conducting a peanut challenge in an infant.

Variation and Trends in Anaphylaxis Care in United States Children's Hospitals

OBJECTIVES

We sought to determine the extent of variation in treatment of children with anaphylaxis.

METHODS

We identified children 1 month to 18 years of age presenting with a primary diagnosis of anaphylaxis to one of the 35 pediatric hospitals included in the Pediatric Health Information System between January 1, 2009, and September 30, 2013. We evaluated the variation in use of β2 agonists, glucocorticoids, histamine-1 (H1) antagonists, histamine-2 (H2) antagonists, inhaled epinephrine, intravenous fluids, and oxygen. We assessed whether variation exists in the rates of hospitalization and 3-day emergency department (ED) revisits and whether a temporal trend exists in the ED visit rate for anaphylaxis.

RESULTS

Among 10,351 children with anaphylaxis, the hospital-level median use of common anaphylaxis therapies varied for β2 agonists (22%, interquartile range [IQR] = 16%-26%), glucocorticoids (71%, IQR = 65%-76%), H1 blockers (60%, IQR = 57%-65%), H2 blockers (53%, IQR = 36%-64%), inhaled epinephrine (2.2%, IQR = 1.3%-3.5%), intravenous fluids (26%, IQR = 13%-41%), and oxygen (2.6%, IQR = 0.8%-4.1%). Hospitalization rates ranged from 12% to 95%, with a median rate of 41%. Anaphylaxis diagnoses rose from 5.7 to 11.7 patients per 10,000 ED visits between 2009 and 2013 (p < 0.001 for trend).

CONCLUSIONS

There is substantial variability in the use of common therapies and hospitalization rates for children cared for in U.S. children's hospitals. Additionally, ED visits for children with anaphylaxis are increasing at U.S. children's hospitals. These findings highlight the need for research defining optimal care for anaphylaxis.

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.