Time trends in Australian hospital anaphylaxis admissions in 1998-1999 to 2011-2012

Paediatric food-induced anaphylaxis hospital presentations in New Zealand

AIM

Globally, rates of paediatric food-induced anaphylaxis (FIA) are increasing. Little data is available regarding the epidemiology of FIA among New Zealand (NZ) children. This study investigated the incidence of paediatric (0-14 years) FIA hospital presentations in NZ over a 10-year period.

METHODS

Ministry of Health public hospital discharge data from 2006 to 2015 were analysed using FIA-related International Classification of Diseases codes (T78.0 - anaphylactic shock due to adverse food reaction and T78.2 - anaphylactic shock unspecified and free text qualifier) to identify acute hospital presentations.

RESULTS

The overall annualised FIA hospital presentation rate was 16.2 per 100 000 children. Subgroup analysis indicated a significantly higher rate in males (19.1/100 000) than in females (13.1/100 000), and among children aged less than 2 years of age (50.5/100 000) compared with older children. Rates among Asian and Pacific children were higher than Māori and NZ European children. In 67.7% of cases, a single specific allergen was suggested by the information provided; among these cases, nuts (48%), specifically peanuts (26%), were the most commonly reported allergen, followed by cow's milk (21%). Time trend analysis showed a 2.8-fold increase in the overall annualised rate for the 10-year period.

CONCLUSION

These findings are consistent with other international studies indicating increasing rates of FIA in children. These data will provide information for a review of NZ paediatric allergy services to ensure current international standards with regard to the equitable delivery of timely, appropriate and accessible care are being met. Reasons for differences by gender, age and ethnicity require further investigation.

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.

IgE promotes type 2 innate lymphoid cells in murine food allergy

BACKGROUND

Mast cells serve an important sentinel function at mucosal barriers and have been implicated as key early inducers of type 2 immune responses in food allergy. The generation of Th2 and IgE following food allergen ingestion is inhibited in the absence of mast cells. Group 2 innate lymphoid cells are also thought to play an important early role in nascent allergic responses.

OBJECTIVE

To test whether IgE-mediated mast cell activation promotes intestinal ILC2 responses following ingestion of food allergens and whether ILC2 amplify food allergy.

METHODS

Two different mouse models of food allergy, one using intraperitoneally ovalbumin (OVA)-primed BALB/c animals and the other using enterally peanut-sensitized inherently atopic IL4raF709 mice, were applied to test the contributions of IgE antibodies and mast cells to ILC2 responses. The effect of ILC2 on mast cell activation and on anaphylaxis was tested.

RESULTS

ILC2 responses were significantly impaired in both models of food allergy in Igh7^-/- mice harbouring a targeted deletion of the gene encoding IgE. A similar reduction in food allergen-induced ILC2 was observed in mast cell-deficient Il4raF709 Kit^W-sh mice, and this was partially corrected by reconstituting these animals using cultured bone marrow mast cells. Mast cells activated ILC2 for IL-13 production in an IL-4Rα-dependent manner. Activated ILC2 amplified systemic anaphylaxis by increasing target tissue sensitivity to mast cell mediators.

CONCLUSIONS AND CLINICAL RELEVANCE

These findings support an important role for IgE-activated mast cells in driving intestinal ILC2 expansion in food allergy and reveal that ILC2, in turn, can enhance responsiveness to the mediators of anaphylaxis produced by mast cells. Strategies designed to inhibit IgE signalling or mast cell activation are likely to inhibit both type 2 immunity and immediate hypersensitivity in food allergy.

Self-reported adverse food reactions and anaphylaxis in the SchoolNuts study: A population-based study of adolescents

BACKGROUND

Adolescents are at the highest risk of death from anaphylaxis, yet few population-based studies have described the frequencies and risk factors for allergic reactions caused by accidental allergen ingestion in this group.

METHODS

We describe the prevalence, frequency, and associated risk factors for recent adverse food reactions in 10- to 14-year-olds in Melbourne, Australia, recruited from a stratified, random, population-based sample of schools (SchoolNuts, n = 9663; 48% response rate). Self-reported food allergy and adverse reaction details, including anaphylaxis, were identified by using a student questionnaire over the past year.

RESULTS

Of 547 students with possible IgE-mediated food allergy, 243 (44.4%; 95% CI, 40.3% to 48.7%) reported a reaction to a food. Fifty-three (9.7%; 95% CI, 7.2% to 12.2%) students reported 93 anaphylaxis episodes. Peanut and tree nuts were the most common food triggers. Among students with current IgE-mediated food allergy, those with resolved or current asthma (adjusted odds ratio [aOR], 1.9 [95% CI, 1.1-1.3] and 1.7 [95% CI, 1.1-2.6]) and those with more than 2 food allergies (aOR, 1.9 [95% CI, 1.1-3.1]) were at greatest risk of any adverse food reaction, and those with nut allergy were most at risk of severe reactions (aOR, 2.9 [95% CI, 1.1-4.4]). Resolved or current asthma was not associated with increased risk of severe reactions (aOR, 0.8 [95% CI, 0.3-2.2] and 1.6 [95% CI, 0.7-3.7]).

CONCLUSIONS

Adolescents with food allergy are frequently exposed to food allergens. Those with asthma and more than 2 food allergies were at the greatest risk for adverse food reactions. Those with nut allergies were most at risk of severe reactions.

Food allergy: is prevalence increasing?

It is generally accepted that the prevalence of food allergy has been increasing in recent decades, particularly in westernised countries, yet high-quality evidence that is based on challenge confirmed diagnosis of food allergy to support this assumption is lacking because of the high cost and potential risks associated with conducting food challenges in large populations. Accepting this caveat, the use of surrogate markers for diagnosis of food allergy (such as nationwide data on hospital admissions for food anaphylaxis or clinical history in combination with allergen-specific IgE (sIgE) measurement in population-based cohorts) has provided consistent evidence for increasing prevalence of food allergy at least in western countries, such as the UK, United States and Australia. Recent reports that children of East Asian or African ethnicity who are raised in a western environment (Australia and United States respectively) have an increased risk of developing food allergy compared with resident Caucasian children suggest that food allergy might also increase across Asian and African countries as their economies grow and populations adopt a more westernised lifestyle. Given that many cases of food allergy persist, mathematical principles would predict a continued increase in food allergy prevalence in the short to medium term until such time as an effective treatment is identified to allow the rate of disease resolution to be equal to or greater than the rate of new cases.

Food Challenge and Community-Reported Reaction Profiles in Food-Allergic Children Aged 1 and 4 Years: A Population-Based Study

BACKGROUND

Oral food challenge is the main tool for diagnosing food allergy, but there is little data on the reaction profiles of young children undergoing challenges, nor how these reactions compare to reactions on accidental ingestion in the community.

OBJECTIVES

To compare reaction profiles from food challenges and parent-reported reactions on accidental ingestion, and assess predictors of severe reactions.

METHODS

HealthNuts is a longitudinal population-based cohort study of 5276 1-year-old infants. Infants underwent skin prick tests and those with identifiable wheals were offered food challenges. Food challenges were repeated at age 4 years in those with previous food allergy or reporting new food allergies. Community-reported reactions were ascertained from parent questionnaires.

RESULTS

Food challenges were undertaken in 916 children at age 1 year and 357 children at age 4 years (a total of 2047 peanut, egg, or sesame challenges). Urticaria was the most common sign in positive challenges at both ages (age 1 year, 88.7%, and age 4 years, 71.2%) although angioedema was significantly more common at age 4 years (40.1%) than at age 1 year (12.9%). Anaphylaxis was equally uncommon at both ages (2.1% and 2.8% of positive challenges at ages 1 and 4 years, respectively) but more common for peanut than for egg (4.5% and 1.2% of positive challenges at ages 1 and 4 years, respectively). The patterns of presenting signs reported during community reactions were similar to those observed in formal food challenges. Serum food-specific IgE levels of 15 kU/L or more were associated with moderate to severe reactions but skin prick test was not.

CONCLUSIONS

There was a shift from the most common presenting reaction of urticaria during food challenges toward more angioedema in older children. Serum food-specific IgE levels were associated with reaction severity.

A Retrospective Study of Korean Adults With Food Allergy: Differences in Phenotypes and Causes

PURPOSE

Increasing in prevalence, food allergy (FA) is becoming an important public health concern. In Korean adults, however, clinical phenotypes and causes of FA have not been studied. We aimed to study common causative allergens and clinical manifestations of FA in Korean adults.

METHODS

This study was conducted as a retrospective review of medical records for 95 patients (≥19 years old) diagnosed with FA from September 2014 to August 2015 at a single university hospital.

RESULTS

In the 95 patients, 181 FA events were recorded. The mean age of first onset of FA symptoms was 34.7±15.8 years. The most frequent causative food was seafood (34.8%); shrimp and crab allergies ranked highest, regardless of age and sex. Among all FA events, there were 47 (26.0%) cases of anaphylaxis and 26 (14.4%) cases of oral allergy syndrome (OAS). Seafood (51.1%) was the most frequent cause of anaphylaxis, followed by grains (14.9%). Most OAS cases were associated with fruits (95.7%). The frequency of fruit-induced FA was significantly higher in males than in females (23.0% vs 8.4%, P=0.011). While no cases of vegetables-induced FA were noted in younger individuals (19 to 30 years), vegetables accounted for 20.5% of FA symptoms in older subjects (≥51 years, P<0.001). Allergic rhinitis (44.2%) and drug allergy (20.0%) were major comorbidities associated with FA. Overall, 29 FA events had cofactors, of which 10 were combined with exercise.

CONCLUSIONS

The major causes of FA in Korean adults were crustacean, fruits, and grains. Interestingly, the clinical manifestations of FA and demographics varied according to type of food allergen.

Individual healthcare plan for allergic children at school: Lessons from a 2015-2016 school year survey

BACKGROUND

The individual healthcare plan (IHP) was implemented in schools in France in 2003 to improve management of allergic children. Our objectives were to assess the practical aspects of IHP (excluding asthma) and allergic reactions occurring at school.

METHODS

Prospective study conducted in the North Department (France) during the 2015/2016 school year. Two questionnaires were developed: one for the school doctors (n = 67) and one for the school principals (n = 2372).

RESULTS

Data from 336 (25%) of the 1325 IHPs (0.24% of children) were collected (mean age: 8 years; food allergy [FA]: 94% [peanut = 44%, nuts = 54%], venom: 4%). Wide variations in emergency kit (EK) medications were observed: antihistamines (84%), oral corticosteroids (79%), adrenaline auto-injectors (70%), and inhaled bronchodilators (65%). Six hundred and seventy (28%) school principals' responses, representing 81% of all IHPs, were analyzed. A total of 1935 EKs were stored (mean: 2.8/school), one or more with adrenaline, by 213 (32%) schools: in the class room (33%), the nursery (14%), or the principal's office (10%). Sixty, mainly, mild-to-moderate allergic reactions (adrenaline injection: 2) occurred in 44 schools (0.09/school/year), in children with previously undocumented allergy in 50%. FA was highly suspected in 92%.

CONCLUSION

Individual healthcare plan is mainly implemented for FA. Anaphylaxis remains rare in the school setting, and FA is often a suspected cause of reaction. Staff training should be improved. Application of the recommendations regarding the content and accessibility of EK and a widespread emergency action plan is needed.

Prevention of Food Allergies

This review summarizes the current state of play with regard to food allergy prevention. Food allergy prevention strategies focused on promoting timely introduction of allergenic foods (predominantly peanut) into the infant diet have recently been introduced in several countries. Additional prevention strategies currently under investigation include optimizing infant vitamin D levels, modulating the gut microbiota through use of probiotics, and preventing eczema to reduce the risk of food sensitization through a damaged skin barrier.

Epidemiology of severe anaphylaxis: can we use population-based data to understand anaphylaxis?

PURPOSE OF REVIEW

The observed increase in incidence of allergic disease in many regions over the past 3 decades has intensified interest in understanding the epidemiology of severe allergic reactions. We discuss the issues in collecting and interpreting these data and highlight current deficiencies in the current methods of data gathering.

RECENT FINDINGS

Anaphylaxis, as measured by hospital admission rates, is not uncommon and has increased in the United Kingdom, the United States, Canada, and Australia over the last 10-20 years. All large datasets are hampered by a large proportion of uncoded, 'unspecified' causes of anaphylaxis. Fatal anaphylaxis remains a rare event, but appears to be increasing for medication in Australia, Canada, and the United States. The rate of fatal food anaphylaxis is stable in the United Kingdom and the United States, but has increased in Australia. The age distribution for fatal food anaphylaxis is different to other causes, with data suggesting an age-related predisposition to fatal outcomes in teenagers and adults to the fourth decade of life.

SUMMARY

The increasing rates of food and medication allergy (the latter exacerbated by an ageing population) has significant implications for future fatality trends. An improved ability to accurately gather and analyse population-level anaphylaxis data in a harmonized fashion is required, so as to ultimately minimize risk and improve management.

Advice about infant feeding for allergy prevention: A confusing picture for Australian consumers?

AIM

Early feeding plays an important role in programming the immune system, particularly the risk of food allergy. There are many infant feeding guides published for consumers available in Australia, with most based on the National Health and Medical Research Council (NHMRC) 2012 Infant Feeding Guidelines for Health Workers and the Australasian Society of Clinical Immunology and Allergy (ASCIA) Infant Feeding Advice for allergy prevention. We sought to compare allergy-specific content of infant feeding educational material written for parents with these two documents.

METHODS

Australian websites of children's hospitals, early child health organisations and consumer groups providing information about diet during pregnancy, breastfeeding and early infancy were compared with NHMRC and ASCIA guidelines.

RESULTS

Twenty-five sets of infant feeding information were identified. Food allergy was discussed in 18 resources. Recommended length of exclusive breastfeeding and timing of commencing solid foods was consistently around 6 months, with some variation in wording. Advice regarding to include and not delay introduction of common allergens into babies' diets was generally consistent with NHMRC and ASCIA recommendations, however the audit identified some resources that still recommended delayed introduction of common allergens.

CONCLUSION

As consumers have access to a plethora of health information it is imperative that information about infant feeding from health-care authorities is simple, evidence-based and consistent to avoid confusion. Use of consensus wording related to infant feeding guidelines to prevent allergies will provide clear messages related to the timing of introduction to solid foods and inclusion of allergens in the early diet.

The revolving door: antibiotic allergy labelling in a tertiary care centre

BACKGROUND

Patients frequently report antibiotic allergies; however, only 10% of labelled patients have a true allergy.

AIM

We investigated the documentation of antibiotic 'allergy' labels (AAL) and the effect of labelling on clinical outcomes, in a West Australian adult tertiary hospital.

METHODS

Retrospective cross-sectional analysis of patients captured in the 2013 and 2014 National Antimicrobial Prescribing Surveys was carried out. Data were collected on documented antibiotic adverse drug reactions, antibiotic cost, prescribing appropriateness, prevalence of multi-drug resistant organisms, length of stay, intensive care admission and readmissions.

RESULTS

Of the 687 patients surveyed, 278 (40%) were aged 70 or above, 365 (53%) were male and 279 (41%) were prescribed antibiotics. AAL were recorded in 122 (18%) patients and the majority were penicillin labels (n = 87; 71%). Details of AAL were documented for 80 of 141 (57%) individual allergy labels, with 61 describing allergic symptoms. Patients with beta-lactam allergy labels received fewer penicillins (P = 0.0002) and more aminoglycosides (P = 0.043) and metronidazole (P = 0.021) than patients without beta-lactam labels. Five patients received an antibiotic that was contraindicated according to their allergy status. Patients with AAL had significantly more hospital readmissions within 4 weeks (P = 0.001) and 6 months (P = 0.025) of discharge, compared with unlabelled patients. The majority (81%) of readmitted labelled patients had major infections.

CONCLUSIONS

AAL are common, but poorly documented in hospital records. Patients with AAL are significantly more likely to require alternative antibiotics and hospital readmissions. There may be a role for antibiotic allergy delabelling to mitigate the clinical and economic burdens for patients with invalid allergy labels.

Death by food

Although death from food is not an uncommon finding in forensic facilities worldwide, the range of underlying lethal mechanisms and associated conditions that should be sought at the time of autopsy is quite disparate. Deaths may occur from i) infectious agents including bacteria, viruses, protozoa, cestodes, nematodes and prions; ii) natural toxins including amanita toxins, tetrodotoxin, ciguatera and scombroid; iii) anaphylaxis; iv) poisoning; v) mechanical issues around airway and gut obstruction and/or perforation; and vi) miscellaneous causes. Food-related deaths are important in terms of global mortality, and thus autopsies need to be comprehensive with full ancillary testing. Medicolegal matters may involve issues concerning likely exposure to infectious agents, possible foods ingested, the declared content and possible components of food, the significance of toxicological analyses, and aspects of duty of care in cases of café coronary syndrome and gastroenteritis while in care.

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.

Anaphylaxis: epidemiology, aetiology and relevance for the clinic

INTRODUCTION

Anaphylaxis is responsible for considerable morbidity and may in some cases prove fatal. Areas covered: This review summarises the findings from recent studies on the epidemiology and aetiology of anaphylaxis and draws on the insights from this work and recent international guidelines to consider the implications for clinical care. Acute management of anaphylaxis is centred on early recognition, treatment with adrenaline (epinephrine) and other essential life-support measures. The importance of longer-term care of patients with a history of or at risk of anaphylaxis are also considered with a view to minimising the risk of further reactions. Tailored individual anaphylaxis management plans should be a routine component of this longer-term care with provision of adrenaline auto-injectors to those at risk of further episodes of anaphylaxis. More generally, there is a need to ensure that there are standard protocols in place to ensure that risks of triggering anaphylaxis are minimised and appropriate acute and long-term care are provided if reactions occur. Expert commentary: It is important to be aware that anaphylaxis may occur in patients of any age, sex or ethnicity. Early recognition and prompt treatment with adrenaline are potentially life-saving. Careful assessment of risk and appropriate long-term management are key to improving long-term outcomes in those at risk of repeat episodes of anaphylaxis.

The prevalence of food allergy and other allergic diseases in early childhood in a population-based study: HealthNuts age 4-year follow-up

BACKGROUND

The HealthNuts study previously reported interim prevalence data showing the highest prevalence of challenge-confirmed food allergy in infants internationally. However, population-derived prevalence data on challenge-confirmed food allergy and other allergic diseases in preschool-aged children remain sparse.

OBJECTIVE

This study aimed to report the updated prevalence of food allergy at age 1 year from the whole cohort, and to report the prevalence of food allergy, asthma, eczema, and allergic rhinitis at age 4 years.

METHODS

HealthNuts is a population-based cohort study with baseline recruitment of 5276 one-year-old children who underwent skin prick test (SPT) to 4 food allergens and those with detectable SPT results had formal food challenges. At age 4 years, parents completed a questionnaire (81.3% completed) and those who previously attended the HealthNuts clinic at age 1 year or reported symptoms of a new food allergy were invited for an assessment that included SPT and oral food challenges. Data on asthma, eczema, and allergic rhinitis were captured by validated International Study of Asthma and Allergies in Childhood questionnaires.

RESULTS

The prevalence of challenge-confirmed food allergy at age 1 and 4 years was 11.0% and 3.8%, respectively. At age 4 years, peanut allergy prevalence was 1.9% (95% CI, 1.6% to 2.3%), egg allergy was 1.2% (95% CI, 0.9% to 1.6%), and sesame allergy was 0.4% (95% CI, 0.3% to 0.6%). Late-onset peanut allergy at age 4 years was rare (0.2%). The prevalence of current asthma was 10.8% (95% CI, 9.7% to 12.1%), current eczema was 16.0% (95% CI, 14.7% to 17.4%), and current allergic rhinitis was 8.3% (95% CI, 7.2% to 9.4%). Forty percent to 50% of this population-based cohort experienced symptoms of an allergic disease in the first 4 years of their life.

CONCLUSIONS

Although the prevalence of food allergy decreased between age 1 year and age 4 years in this population-based cohort, the prevalence of any allergic disease among 4-year-old children in Melbourne, Australia, is remarkably high.

Adrenaline overdose in pediatric anaphylaxis: a case report

Background

Adrenaline is the standard treatment for anaphylaxis but appropriate administration remains challenging, and iatrogenic overdose is easily overlooked. Despite the established importance of pediatric blood pressure measurement, its use remains inconsistent in clinical practice.

Case presentation

We report a case of adrenaline overdose in a 9-year-old white boy with anaphylaxis, where signs of adrenaline overdose were indistinguishable from progressive shock until blood pressure measurement was taken.

Conclusions

The consequences of under-dosing adrenaline in anaphylaxis are well-recognized, but the converse is less so. Blood pressure measurement should be a routine part of pediatric assessment as it is key to differentiating adrenaline overdose from anaphylactic shock.

In-flight allergic emergencies

Allergic and hypersensitivity reactions such as anaphylaxis and asthma exacerbations may occur during air travel. Although the exact incidence of in-flight asthma and allergic emergencies is not known, we have concerns that this subject has not received the attention it warrants. There is a need to provide passengers at risk and airlines with the necessary measures to prevent and manage these emergencies. A review of the epidemiology, management and approaches to prevention of allergic and asthma emergencies during air travel is presented with the goal of increasing awareness about these important, potentially preventable medical events.

Allergen Immunotherapy

Allergies affect a large proportion of the population. Allergies can adversely affect productivity, sleep, and quality of life and can lead to life-threatening reactions. Allergies can spread to affect multiple organ systems. Allergen immunotherapy is the only therapy that can change the natural history of allergic disease.

Changes to infant feeding guidelines: Relevance to dermatologists

The newly revised Australian Infant Feeding Guidelines recommends that all infants, including those at high risk of allergy, be introduced foods traditionally considered allergenic (such as peanut butter, dairy, wheat and egg) within the first year of life. High-risk infants are those with early onset eczema (<3-months old) or with moderate to severe eczema not responding to treatment (<6-months old). Eczema can also represent a symptom of allergy presentation and the recommended introduction of some foods in this group may lead to allergic reactions at home. Although there have been no reported deaths from gradual food introduction to infants at home and cohort studies have only reported mild to moderate reactions, there is anecdotal evidence that more severe reactions can occur rarely. Allergic reactions, even if they are not life-threatening, can be a terrifying experience for parents. Dermatologists play an important role when dealing with high-risk infants in promoting the message of early allergenic food introduction yet also instigating appropriate allergy testing when necessary. This short review aims to provide an update to Australasian dermatologists on the newly revised Australian Infant Feeding Guidelines and provide a food allergy screening pathway for high-risk infants prior to commencement of allergenic foods.

[Food-induced anaphylaxis - data from the anaphylaxis registry]

Anaphylactic reactions due to food occur in the context of food allergy and, together with venom and drugs, are the most frequent elicitors of severe allergic reactions. In small children the most frequent elicitors of severe allergic reactions according to data from the anaphylaxis registry are hen's egg and milk, whereas in school children peanut and hazelnut are frequent elicitors of allergic reactions. Other frequent elicitors of anaphylactic reactions in childhood are wheat and soy. In adults the most frequent elicitors of severe allergic reactions due to food, based on data from the anaphylaxis registry, are wheat, soy, celery, shellfish and hazelnut. Rare elicitors of food-induced anaphylaxis in German-speaking countries are mustard and cabbage. However, the panel of rare elicitors of food-induced anaphylaxis show regional differences. As of March 2015, 17 cases of fatal anaphylaxis were registered and among these seven were food-induced. Co-factors can either trigger the elicitation of a severe allergic reaction or affect its severity. Among such co-factors are physical activity, the intake of certain drugs, and psychological stress. The data on the role of cofactors is sparse. The management of food-induced anaphylaxis includes acute management according to current guidelines, but also long-term management, which should include educational measures regarding treatment but also information about the food allergen in daily life.

Maternal Folic Acid Supplementation during Pregnancy and Childhood Allergic Disease Outcomes: A Question of Timing?

Since the early 1990s, maternal folic acid supplementation has been recommended prior to and during the first trimester of pregnancy, to reduce the risk of infant neural tube defects. In addition, many countries have also implemented the folic acid fortification of staple foods, in order to promote sufficient intakes amongst women of a childbearing age, based on concerns surrounding variable dietary and supplementation practices. As many women continue to take folic acid supplements beyond the recommended first trimester, there has been an overall increase in folate intakes, particularly in countries with mandatory fortification. This has raised questions on the consequences for the developing fetus, given that folic acid, a methyl donor, has the potential to epigenetically modify gene expression. In animal studies, folic acid has been shown to promote an allergic phenotype in the offspring, through changes in DNA methylation. Human population studies have also described associations between folate status in pregnancy and the risk of subsequent childhood allergic disease. In this review, we address the question of whether ongoing maternal folic acid supplementation after neural tube closure, could be contributing to the rise in early life allergic diseases.

True rise in anaphylaxis incidence: Epidemiologic study based on a national health insurance database

The incidence trend of anaphylaxis in Asia is not well investigated. The aim of this study is to estimate the entire population-based incidence of anaphylaxis in Korea using a nationwide administrative database.Data over a 7-year period (2008-2014) was obtained from the Korean National Health Insurance (NHI) claims database which covers 97.9% of the entire Korean population. Using diagnosis codes from the International Classification of Diseases-10 for anaphylaxis (T78.0, T78.2, T80.5, and T88.6), we identified the annual number of patients who had visited any hospital with a primary diagnosis of anaphylaxis. Incidence rates were calculated using the population distribution data of all NHI beneficiaries.The incidence of anaphylaxis in Korea was 32.19 episodes per 100,000 person-years in 2014, which nearly doubled from 2008 (16.02 episodes per 100,000 person-years). The incidence of anaphylaxis increased continuously throughout these years regardless of gender and age groups (P for trend < 0.001). Female was significantly less predisposed than male (adjusted odds ratio [OR], 0.69; 95% confident interval [CI], 0.66-0.72; P < 0.001). The incidence was the lowest in 0 to 19 age group and the highest in 40 to 69 age group (adjusted OR, 2.41; 95% CI, 2.29-2.54; P < 0.001).In conclusion, we report the increasing time trend of anaphylaxis incidence rates using nationwide claims database for the first time in Asia.

Nut allergy prevalence and differences between Asian-born children and Australian-born children of Asian descent: a state-wide survey of children at primary school entry in Victoria, Australia

BACKGROUND

Asian infants born in Australia are three times more likely to develop nut allergy than non-Asian infants, and rates of challenge-proven food allergy in infants have been found to be unexpectedly high in metropolitan Melbourne. To further investigate the risk factors for nut allergy, we assessed the whole-of-state prevalence distribution of parent-reported nut allergy in 5-year-old children entering school.

METHODS

Using the 2010 School Entrant Health Questionnaire administered to all 5-year-old children in Victoria, Australia, we assessed the prevalence of parent-reported nut allergy (tree nut and peanut) and whether this was altered by region of residence, socio-economic status, country of birth or history of migration. Prevalence was calculated as observed proportion with 95% confidence intervals (CI). Risk factors were evaluated using multivariable logistic regression and adjusted for appropriate confounders.

RESULTS

Parent-reported nut allergy prevalence was 3.1% (95% CI 2.9-3.2) amongst a cohort of nearly 60 000 children. It was more common amongst children of mothers with higher education and socio-economic index and less prevalent amongst children in regional Victoria than in Melbourne. While children born in Australia to Asian-born mothers (aOR 2.67, 95% CI 2.28-3.27) were more likely to have nut allergy than non-Asian children, children born in Asia who subsequently migrated to Australia were at decreased risk of nut allergy (aOR 0.1, 95% CI 0.03-0.31).

CONCLUSION

Migration from Asia after the early infant period appears protective for the development of nut allergy. Additionally, rural regions have lower rates of nut allergy than urban areas.

Specific oral tolerance induction in childhood

Food allergy continues to be a significant public health concern for which there are no approved treatments and management strategies primarily include allergen avoidance and pharmacological measures for accidental exposures. Food allergy is thought to result from either a failure to establish oral tolerance or the breakdown of existing oral tolerance, and therefore, experimental preventative and treatment strategies are now aimed at inducing specific oral tolerance. This may occur in infancy prior to the development of food allergy through the optimal timing of dietary exposure (primary oral tolerance induction) or as a treatment for established food allergy through oral immunotherapy (secondary oral tolerance induction). Trials examining the effectiveness of early dietary allergen exposure to prevent food allergy have yielded promising results for peanut allergy but not so for other allergens, although the results of several trials are yet to be published. Although infant feeding guidelines no longer advise to avoid allergenic foods and exposure to food allergens orally is an important step in inducing food tolerance by the immune system, evidence regarding the optimal timing, dose and form of these foods into the infant's diet is lacking. Likewise, oral immunotherapy trials appear promising for inducing desensitization; however, the long-term efficacy in achieving sustained desensitization and optimal protocols to achieve this is unknown. More research is needed in this emerging field.

[Anaphylaxis in children: What pediatricians should know]

Anaphylaxis is a severe potentially life-threatening allergic emergency that has been increasing over the last two decades, especially in young children. Anaphylaxis deaths remain rare, in particular in children, and their frequency is stable during this period. Food is the main anaphylaxis trigger in children, notably to cow's milk, peanuts, and tree nuts. In infants, the recognition of anaphylaxis may be difficult. Vomiting, urticaria, and laryngeal edema are more frequent at this age. Cardiovascular involvement is rare, most often encountered in adolescence. A history of asthma or atopy, allergy to particular foods such as peanuts and tree nuts, and adolescence are some risk factors for anaphylaxis and more severe reactions. First-line treatment is intramuscular adrenaline for all patients experiencing anaphylaxis. There are no absolute contra-indications. Guidelines for the prescription of the adrenaline auto-injector and for establishing a personalized care project in allergic children at school have recently been updated. Recognition of anaphylaxis and treatment should also be improved.

Mechanisms of anaphylaxis in human low-affinity IgG receptor locus knock-in mice

BACKGROUND

Anaphylaxis can proceed through distinct IgE- or IgG-dependent pathways, which have been investigated in various mouse models. We developed a novel mouse strain in which the human low-affinity IgG receptor locus, comprising both activating (hFcγRIIA, hFcγRIIIA, and hFcγRIIIB) and inhibitory (hFcγRIIB) hFcγR genes, has been inserted into the equivalent murine locus, corresponding to a locus swap.

OBJECTIVE

We sought to determine the capabilities of hFcγRs to induce systemic anaphylaxis and identify the cell types and mediators involved.

METHODS

hFcγR expression on mouse and human cells was compared to validate the model. Passive systemic anaphylaxis was induced by injection of heat-aggregated human intravenous immunoglobulin and active systemic anaphylaxis after immunization and challenge. Anaphylaxis severity was evaluated based on hypothermia and mortality. The contribution of receptors, mediators, or cell types was assessed based on receptor blockade or depletion.

RESULTS

The human-to-mouse low-affinity FcγR locus swap engendered hFcγRIIA/IIB/IIIA/IIIB expression in mice comparable with that seen in human subjects. Knock-in mice were susceptible to passive and active anaphylaxis, accompanied by downregulation of both activating and inhibitory hFcγR expression on specific myeloid cells. The contribution of hFcγRIIA was predominant. Depletion of neutrophils protected against hypothermia and mortality. Basophils contributed to a lesser extent. Anaphylaxis was inhibited by platelet-activating factor receptor or histamine receptor 1 blockade.

CONCLUSION

Low-affinity FcγR locus-switched mice represent an unprecedented model of cognate hFcγR expression. Importantly, IgG-related anaphylaxis proceeds within a native context of activating and inhibitory hFcγRs, indicating that, despite robust hFcγRIIB expression, activating signals can dominate to initiate a severe anaphylactic reaction.

Randomized placebo-controlled trial of hen's egg consumption for primary prevention in infants

BACKGROUND

Hen's egg is the most common cause of food allergy in early childhood.

OBJECTIVE

We investigated the efficacy and safety of early hen's egg introduction at age 4 to 6 months to prevent hen's egg allergy in the general population.

METHODS

This randomized, placebo-controlled trial included 4- to 6-month-old infants who were not sensitized against hen's egg, as determined based on specific serum antibodies (IgE). These infants were randomized to receive either verum (egg white powder) or placebo (rice powder) added to the first weaning food 3 times a week under a concurrent egg-free diet from age 4 to 6 until 12 months. The primary outcome was sensitization to hen's egg (increased specific serum IgE levels) by age 12 months. Hen's egg allergy (secondary outcome) was confirmed by double-blind, placebo-controlled food challenges.

RESULTS

Among 406 screened infants, 23 (5.7%) had hen's egg-specific IgE before randomization. Seventeen of 23 underwent subsequent double-blind, placebo-controlled food challenges, and 16 were confirmed as allergic, including 11 with anaphylactic reactions. Of the 383 nonsensitized infants (56.7% male), 184 were randomized to verum and 199 to placebo. At 12 months of age, 5.6% of the children in the verum group were hen's egg sensitized versus 2.6% in the placebo group (primary outcome; relative risk, 2.20; 95% CI, 0.68-7.14; P = .24), and 2.1% were confirmed to have hen's egg allergy versus 0.6% in the placebo group (relative risk, 3.30; 95% CI, 0.35-31.32; P = .35).

CONCLUSION

We found no evidence that consumption of hen's egg starting at 4 to 6 months of age prevents hen's egg sensitization or allergy. In contrast, it might result in frequent allergic reactions in the community considering that many 4- to 6-month-old infants were already allergic to hen's egg.

Epigenetic modifications: mechanisms of disease and biomarkers of food allergy

The rise in IgE-mediated food allergy in recent times is the likely result of gene-environment interactions mediated via epigenetic pathways. As epigenetic modifications, including DNA methylation, are at the interface between the environment and the genome, they may be ideal biomarkers of modifiable disease pathways. High-throughput methylation profiling of immune cell subtypes or whole blood from patients allows the identification of disease specific epigenetic variants. If faithfully tracking with disease parameters, these 'signatures' may have clinical applications as biomarkers of disease or therapeutic response. Development of such tools will depend on a number of factors, including determining the most appropriate experimental approach, analysis methodology, patient groups, and informative target cells/tissues. Here we discuss these potential applications and their implications for food allergy practise.

Advances and highlights in mechanisms of allergic disease in 2015

This review highlights some of the advances in mechanisms of allergic disease, particularly anaphylaxis, including food allergy, drug hypersensitivity, atopic dermatitis (AD), allergic conjunctivitis, and airway diseases. During the last year, a mechanistic advance in food allergy was achieved by focusing on mechanisms of allergen sensitization. Novel biomarkers and treatment for mastocytosis were presented in several studies. Novel therapeutic approaches in the treatment of atopic dermatitis and psoriasis showed that promising supplementation of the infant's diet in the first year of life with immunoactive prebiotics might have a preventive role against early development of AD and that therapeutic approaches to treat AD in children might be best directed to the correction of a TH2/TH1 imbalance. Several studies were published emphasizing the role of the epithelial barrier in patients with allergic diseases. An impaired skin barrier as a cause for sensitization to food allergens in children and its relationship to filaggrin mutations has been an important development. Numerous studies presented new approaches for improvement of epithelial barrier function and novel biologicals used in the treatment of inflammatory skin and eosinophilic diseases. In addition, novel transcription factors and signaling molecules that can develop as new possible therapeutic targets have been reported.

Regional differences in vitamin D levels and incidence of food-induced anaphylaxis in South Korea

BACKGROUND

Previous studies have suggested low vitamin D as a potential risk factor for food allergy/anaphylaxis. However, few studies have investigated the association between vitamin D and food-induced anaphylaxis (FIA) in South Korea.

OBJECTIVE

To examine regional differences in serum vitamin D levels and FIA incidence.

METHODS

We used nationwide data collected from 2011 to 2013. Data on vitamin D were obtained from the Korea National Health and Nutrition Examination Survey; data on FIA were obtained from the Health Insurance and Assessment Service. Districts were grouped into region 1 (lower solar radiation) and region 2 (higher solar radiation). We examined differences in FIA incidence and vitamin D levels between the regions, adjusting for age.

RESULTS

The study included 2,814 patients with FIA and 15,367 people with available serum vitamin D measurements. Age-adjusted FIA incidence was 2.2 per 100,000 person-years in region 1 and 1.8 per 100,000 person-years in region 2 (relative risk, 1.23; 95% confidence interval, 1.09-1.39). Age-adjusted serum vitamin D levels were 16.5 ng/mL in region 1 and 17.8 ng/mL in region 2 (mean difference, 1.3 ng/mL; 95% confidence interval, 0.9-1.9). After stratification by age, sex, and area of residence, region 1 still had higher FIA incidence and lower vitamin D levels than region 2.

CONCLUSION

The present study found a higher incidence of FIA in regions with lower vitamin D levels in the population. Further investigation is necessary to identify any direct associations between vitamin D and food allergy/anaphylaxis.

2015 update of the evidence base: World Allergy Organization anaphylaxis guidelines

The World Allergy Organization (WAO) Guidelines for the assessment and management of anaphylaxis provide a unique global perspective on this increasingly common, potentially life-threatening disease. Recommendations made in the original WAO Anaphylaxis Guidelines remain clinically valid and relevant, and are a widely accessed and frequently cited resource. In this 2015 update of the evidence supporting recommendations in the Guidelines, new information based on anaphylaxis publications from January 2014 through mid- 2015 is summarized. Advances in epidemiology, diagnosis, and management in healthcare and community settings are highlighted. Additionally, new information about patient factors that increase the risk of severe and/or fatal anaphylaxis and patient co-factors that amplify anaphylactic episodes is presented and new information about anaphylaxis triggers and confirmation of triggers to facilitate specific trigger avoidance and immunomodulation is reviewed. The update includes tables summarizing important advances in anaphylaxis research.