Food Allergy Sensitization and Presentation in Siblings of Food Allergic Children

A comprehensive guide to food allergy management for the general pediatrician

There has been an increase in the prevalence of food allergy among children in the United States. Pediatricians play a pivotal role in caring for children with food allergy, as they are often the first point of contact and enjoy longitudinal relationships with families. In this review, we discuss the epidemiology, risk factors, presentation, diagnosis, and management of food allergy. We also discuss special considerations for patients with food allergy, including nutritional risks and psychosocial stressors that may negatively influence children's wellbeing. Our goal is to provide a concise yet comprehensive guide for general pediatricians so they may feel confident providing high-quality care for patients with food allergy.

The Role of Food Allergy in Atopic Dermatitis

Atopic dermatitis (AD) and food allergies are 2 atopic conditions that tend to develop early in life. Their interrelationship has been a topic of controversy and many studies. The presence of atopic dermatitis in infancy and early childhood, particularly if severe, is a risk factor for the development of immunoglobulin E (IgE) -mediated food allergies. While it is common for children with AD to demonstrate extensive sensitization to foods, serum IgE testing is not always indicative of clinical allergy.

Timing of Food Introduction and Allergy Prevention: An Update

Recommendations about allergy prevention through diet are rapidly changing. In just the past several years, multiple organizations have provided updated guidance and recommendations about infant feeding based on recent studies and meta-analyses. In addition to the increased number of studies supporting the benefit of early introduction of allergenic foods, in particular peanut and egg, recent studies demonstrate that infant and maternal diet diversity may also reduce risk of food allergy and atopy. Skin emollients have not been found to be helpful in prevention of food allergy, and more evidence is needed to determine if emollients play a role in prevention of atopic dermatitis.

Food Allergy

Food allergy is a growing health problem affecting both pediatric and adult patients. Food allergies are often immunoglobulin E (IgE) mediated but other food-induced non-IgE-mediated diseases exist. Diagnosis of food allergy relies on the combination of clinical and reaction history, skin and IgE testing as well as oral food challenges. Although oral immunotherapy has been able to achieve sustained unresponsiveness in some patients, no cure for food allergies has been found to date. Avoidance of the inciting food as well as availability of epinephrine autoinjectors remains the mainstay of treatment.

Targeting Food Allergy with Probiotics

The globally dramatic increase in food allergy prevalence and severity is demanding effective preventive and therapeutic strategies. Food allergy derives from a defect of immune tolerance mechanisms. Immune tolerance is modulated by gut microbiome composition and function, and gut microbiome dysbiosis has been associated with the development of food allergy. Selected probiotic strains could regulate immune tolerance mechanisms. The mechanisms are multiple and are still not completely defined. Increasing evidence is providing useful information on the choice of optimal bacterial species/strains, dosage, and timing for intervention. The increased knowledge on the crucial role played by postbiotic gut microbiome-derived metabolites, such as butyrate, is also opening the way to a post- biotic approach in the stimulation of immune tolerance.

Epithelial Barrier Theory: The Role of Exposome, Microbiome, and Barrier Function in Allergic Diseases

Allergic diseases are a major public health problem with increasing prevalence. These immune-mediated diseases are characterized by defective epithelial barriers, which are explained by the epithelial barrier theory and continuously emerging evidence. Environmental exposures (exposome) including global warming, changes and loss of biodiversity, pollution, pathogens, allergens and mites, laundry and dishwasher detergents, surfactants, shampoos, body cleaners and household cleaners, microplastics, nanoparticles, toothpaste, enzymes and emulsifiers in processed foods, and dietary habits are responsible for the mucosal and skin barrier disruption. Exposure to barrier-damaging agents causes epithelial cell injury and barrier damage, colonization of opportunistic pathogens, loss of commensal bacteria, decreased microbiota diversity, bacterial translocation, allergic sensitization, and inflammation in the periepithelial area. Here, we review scientific evidence on the environmental components that impact epithelial barriers and microbiome composition and their influence on asthma and allergic diseases. We also discuss the historical overview of allergic diseases and the evolution of the hygiene hypothesis with theoretical evidence.

A review of food allergy panels and their consequences

Serum immunoglobulin E (IgE) assays to food specific IgE (s-IgE) are useful tools for the confirmation of clinical suspicion of food allergy. However, the specificity of these assays is poor given that sensitization is much more common than clinical food allergy. Therefore, the use of broad panels to assess sensitization to multiple foods often leads to overdiagnosis and unnecessary food avoidance. Unintended consequences that may occur as a result include physical harm, psychological harm, financial cost, opportunity cost, and even worsening of existing health care disparities. Although current guidelines recommend against the use of s-IgE food panel testing, these tests are widely available and frequently used. To limit the negative impacts of s-IgE food panel testing, further work is needed to effectively spread the message that these food panels may cause unintended harm to patients and families.

Allergen Differences and Correlation Analysis in Siblings Diagnosed with Respiratory Allergic Diseases

INTRODUCTION

Many parents of children with allergies are worried whether their subsequent children will have allergic reactions to the same allergens. Much of the current research on sibling allergens has been focused on twins; however, in real life, very few children are twins. Our study provides an opportunity to initially explore the sensitivity to allergens in siblings diagnosed with respiratory allergic diseases.

METHODS

Siblings diagnosed with bronchial asthma and/or allergic rhinitis in the Outpatient Department of Allergy Department of Yantai Yuhuangding Hospital from January 2018 to December 2021 were selected. The siblings were divided into elder group and younger group. Data of gender, age, feeding history, serum total IgE (TIgE), absolute eosinophil counts, and allergen-specific IgE (sIgE) were collected and analyzed. The sIgEs of allergens were divided into six categories and analyzed.

RESULTS

A total of 98 sibling pairs of patients were included in this study. There were no differences in the positive rates of the different types of allergens, TIgE values, and the absolute eosinophil values between the elder and younger groups and between different genders. Logistic regression analysis indicated that the elder siblings allergic to dust mites, fungi, weed pollens, or food had a statistically significant increased risk of having their younger sibling sensitive to these types of allergens (all p <0.05), and the risk of allergy to dust mites, weed pollens, and tree pollens of younger group increased with age (all p <0.05). Except for the sIgE values of dust mites, the sIgE values of the other allergens were significantly correlated between the two groups (all p <0.05).

CONCLUSION

The positive rates of different allergens were similar between siblings. Elder siblings with dust mites, fungi, weed pollen, or food allergen positivity will have younger siblings sensitive to the same types of allergens.

Multi-omics profiling approach in food allergy

The prevalence of food allergy (FA) among children is increasing, affecting nearly 8% of children, and FA is the most common cause of anaphylaxis and anaphylaxis-related emergency department visits in children. Importantly, FA is a complex, multi-system, multifactorial disease mediated by food-specific immunoglobulin E (IgE) and type 2 immune responses and involving environmental and genetic factors and gene-environment interactions. Early exposure to external and internal environmental factors largely influences the development of immune responses to allergens. Genetic factors and gene-environment interactions have established roles in the FA pathophysiology. To improve diagnosis and identification of FA therapeutic targets, high-throughput omics approaches have emerged and been applied over the past decades to screen for potential FA biomarkers, such as genes, transcripts, proteins, and metabolites. In this article, we provide an overview of the current status of FA omics studies, namely genomic, transcriptomic, epigenomic, proteomic, exposomic, and metabolomic. The current development of multi-omics integration of FA studies is also briefly discussed. As individual omics technologies only provide limited information on the multi-system biological processes of FA, integration of population-based multi-omics data and clinical data may lead to robust biomarker discovery that could translate into advances in disease management and clinical care and ultimately lead to precision medicine approaches.

Food Allergy

Food allergy is a growing health problem affecting both pediatric and adult patients. Food allergies are often immunoglobulin E (IgE) mediated but other food-induced non-IgE-mediated diseases exist. Diagnosis of food allergy relies on the combination of clinical and reaction history, skin and IgE testing as well as oral food challenges. Although oral immunotherapy has been able to achieve sustained unresponsiveness in some patients, no cure for food allergies has been found to date. Avoidance of the inciting food as well as availability of epinephrine autoinjectors remains the mainstay of treatment.

B cell repertoire in children with skin barrier dysfunction supports altered IgE maturation associated with allergic food sensitization

The skin is a major immune organ and skin barrier dysfunction is a major risk factor for the development of the inappropriate immune response seen in allergic disease. Skin barrier disruption alters the landscape of antigens experienced by the immune system and the downstream impacts on the antibody repertoire remain poorly characterized, particularly for the IgE isotype responsible for allergic specificity and in early life, when allergic disease is developing. In this study, we sequenced antibody gene repertoires from a large and well-characterized cohort of children with atopic dermatitis and found that food sensitization was associated with lower mutation frequencies in the IgE compartment. This trend was abrogated in children living with pets during the first year of life. These results elucidate potential molecular mechanisms underlying the protective effects of pet ownership and non-antiseptic environs reported for allergic disease, and the hygiene hypothesis more broadly. We also observed increased IgE diversity and increased isotype-switching to the IgE isotype, suggesting that B cell development, particularly isotype-switching, is heavily altered in the those with food allergen sensitizations relative to those without food allergen sensitizations. Unlike for food antigens, aeroallergen sensitization exhibited no effect on IgE mutation or diversity. Consistent patterns of antibody rearrangement were associated with food allergen sensitization in subjects with atopic dermatitis. Thus, we propose the Immune Repertoire in Atopic Disease (IRAD) score, to quantify this repertoire shift and to aid clinically in patient diagnosis and risk stratification.

Anaphyl-Crisis: Rising Rates of Pediatric Anaphylaxis

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Biomarkers and their Clinical Applications in Pediatrics

Biomarker studies are becoming increasingly interesting for many fields of medicine. The use of biomarkers in medicine is involved in detecting diseases and supporting diagnosis and treatment decisions. New research and new discoveries on the molecular basis of the disease show that there may be a number of promising new biomarkers for use in daily clinical practice. Clinical trials in children lag behind adult research both in quality and quantity. The number of biomarkers validated to optimize pediatric patient management is limited. In the pathogenesis of many diseases, it should not be extrapolated to the pediatric clinical setting, taking into account that biomarkers that are effective in adults are clearly different in children and that ontogeny directly affects disease development and therapeutic response in children. The search for ideal biomarkers or markers that can make an early and definitive diagnosis in neonatal sepsis is still ongoing. The ideal biomarker for pediatric diseases should be costeffective, noninvasive, applicable to pediatric specific diseases, and its results should correspond to age-related physiological changes. Lactate, troponin and B-type natriuretic peptide are valuable biomarkers in the evaluation and management of critically ill children with cardiac disease. Tumor markers in children are biochemical substances used in the clinical treatment of pediatric tumors and to detect the presence of cancer (regression or progression). In this chapter, current and brief information about biomarkers and their clinical applications used in the diagnosis and monitoring of pediatric diseases is presented.;

The links between allergen exposure and sensitization in children and adolescents: an overview for the clinician

INTRODUCTION

The links between allergen exposure and sensitization are complex and depend not only on the type of allergen but on various genetic and environmental factors.

AREAS COVERED

This review discusses the link between allergen exposure and atopic sensitization for different types of allergens and the factors that mediate or affect this link. For the purposes of this review search of PubMed was undertaken to identify English language articles using the terms 'sensitization' and 'allergen exposure' and 'children/or adolescents.'

EXPERT OPINION

Regarding food sensitization, the available data for peanuts and eggs suggest that there is a window period between 4 and 6 months of age when the introduction of these foods may limit sensitization and clinically overt allergy to the respective foods. As far as it concerns aeroallergens, it seems that there is a complex and variable relationship between mite exposure and specific sensitization especially if the exposure occurs early in life. Early exposure to dog allergens does not seem to be associated with specific sensitization; regarding cats, the results are still inconsistent. Several factors may mediate the relationship between early exposure to allergens and the development of sensitization or clinical allergy.

Trends in the contributions of atopic family history to pediatric food sensitization and allergy

OBJECTIVE

Family history of atopic diseases (FHA) contributes to food allergy (FA). But little is known whether FHA primarily increases IgE-mediated, non-IgE-mediated FA, or both. And the trends in the contributions of FHA to food sensitization (FS) and FA remain unclear. We aim to clarify the associations among FHA, FS and FA and to understand the trends in the contributions of FHA to FS and FA.

METHODS

We used chi-square test and mediating effect model to analyze the associations among FHA, FS and FA through comparisons between two cross-sectional investigations on FA in children under 2 years old in 2009 and 2019.

RESULTS

In 2009 and 2019, the positive FHA proportion tended to be increasing without significance (28.9% to 31.6%, P = 0.39). Subgroup analysis showed the FS rate in FA group decreased significantly (37/39 to 44/62, P = 0.003). In 2009, the FS rate and FA prevalence were higher in FHA (+) group than in FHA (-) group (26% vs. 14.7%, P = 0.008 and 15% vs. 7.7%, P = 0.03), and FS had a complete mediating effect on the association between FHA and FA (Z = 2.54, P = 0.011), but the results lost significance in 2019.

CONCLUSIONS

The association between FHA and FA was completely mediated by FS, which means FHA mainly increases IgE-mediated FA. And the contributions of FHA to FS and FA tended to be stabilized or even diminished, which means FHA alone could no longer be enough to screen high-risk children.

Differences in oral food challenge reaction severity based on increasing age in a pediatric population

BACKGROUND

Food allergy reactions range from mild to severe with differences in age appearing to be an important factor associated with reaction severity.

OBJECTIVE

To define differences in oral food challenge (OFC) reaction severity in pediatric patients from infancy to adolescence using objective clinical outcomes and standardized reaction grading tools.

METHODS

Retrospective review of all positive OFC results at 2 large institutions between September 2016 and February 2019. Reaction severity was defined by presence of cardiovascular, neurologic, lower respiratory, or laryngeal symptoms, epinephrine requirement, and grading using 2 established food allergy reaction scales.

RESULTS

Infants and toddlers had fewer reactions involving cardiovascular, neurologic, lower respiratory, or laryngeal symptoms compared with older age groups. Epinephrine was also required less frequently during reactions in infants and toddlers, compared with older age groups. There was no difference in reaction severity in infants and toddlers based on clinical history of eczema. Increasing age was significantly correlated with increased epinephrine requirement (R² = 0.12, P = .002), elevated Consortium of Food Allergy Research score (R² = .012, P = .003), and approached significance for increased Practical Allergy score (R² = .005, P = .05). History of asthma and sesame allergy were identified to be positively correlated with more severe reactions.

CONCLUSION

Infants and young toddlers have less severe reactions during OFCs compared with older age groups supporting early food introduction practices. In children under 12 months of age, severe reactions are most rare calling into question screening practices using specific allergy testing before food introduction. Standardized reaction grading tools may be valuable instruments to categorize reaction severity during OFCs.

Stem Cell Factor Neutralization Protects From Severe Anaphylaxis in a Murine Model of Food Allergy

Food allergy is a growing public health problem with ~15 million people affected in the United States. In allergic food disease, IgE on mast cells bind to ingested antigens leading to the activation and degranulation of mast cells. Stem cell factor (SCF) is mast cell growth and activation factor that is required for peripheral tissue mast cells. We targeted a specific isoform of SCF, the larger 248 amino acid form, that drives peripheral tissue mast cell differentiation using a specific monoclonal antibody in a model of food allergy. Ovalbumin sensitized and intragastrically challenged mice were monitored for symptoms of anaphylaxis including respiratory distress, diarrhea, and a reduction in body temperature. During the second week of challenges, allergic mice were injected with an antibody to block SCF248 or given IgG control. Mice treated with α-SCF248 had a decreased incidence of diarrhea and no reduction in body temperature suggesting a reduction in anaphylaxis compared to IgG control treated animals. Re-stimulated mesenteric lymph nodes indicated that α-SCF248 treated mice had decreased OVA-specific Th2 cytokine production compared to IgG control treated allergic animals. The reduction of food induced anaphylaxis was accompanied by a significant reduction in gut leak. The mesenteric lymph node cells were analyzed by flow cytometry and showed a decrease in the number of type 2 innate lymphoid cells in mice injected with α-SCF248. Morphometric enumeration of esterase+ mast cells demonstrated a significant reduction throughout the small intestine. Using a more chronic model of persistent food-induced anaphylaxis, short term therapeutic treatment with α-SCF248 during established disease effectively blocked food induced anaphylaxis. Together, these data suggest that therapeutically blocking SCF248 in food allergic animals can reduce the severity of food allergy by reducing mast cell mediated disease activation.

Current insights into the genetics of food allergy

Food allergy (FA), a growing public health burden in the United States, and familial aggregation studies support strong roles for both genes and environment in FA risk. Deepening our understanding of the molecular and cellular mechanisms driving FAs is paramount to improving its prevention, diagnosis, and clinical management. In this review, we document lessons learned from the genetics of FA that have aided our understanding of these mechanisms. Although current genetic association studies suffer from low power, heterogeneity in definition of FA, and difficulty in our ability to truly disentangle FA from food sensitization (FS) and general atopy genetics, they reveal a set of genetic loci, genes, and variants that continue to implicate the importance of barrier and immune function genes across the atopic march, and FA in particular. The largest reported effects on FA are from MALT1 (odds ratio, 10.99), FLG (average odds ratio, ∼2.9), and HLA (average odds ratio, ∼2.03). The biggest challenge in the field of FA genetics is to elucidate the specific mechanism of action on FA risk and pathogenesis for these loci, and integrative approaches including genetics/genomics with transcriptomics, proteomics, and metabolomics will be critical next steps to translating these genetic insights into practice.

Advances and novel developments in environmental influences on the development of atopic diseases

Although genetic factors play a role in the etiology of atopic disease, the rapid increases in the prevalence of these diseases over the last few decades suggest that environmental, rather than genetic factors are the driving force behind the increasing prevalence. In modern societies, there is increased time spent indoors, use of antibiotics, and consumption of processed foods and decreased contact with farm animals and pets, which limit exposure to environmental allergens, infectious parasitic worms, and microbes. The lack of exposure to these factors is thought to prevent proper education and training of the immune system. Increased industrialization and urbanization have brought about increases in organic and inorganic pollutants. In addition, Caesarian birth, birth order, increased use of soaps and detergents, tobacco smoke exposure and psychosomatic factors are other factors that have been associated with increased rate of allergic diseases. Here, we review current knowledge on the environmental factors that have been shown to affect the development of allergic diseases and the recent developments in the field.

A Consensus Approach to the Primary Prevention of Food Allergy Through Nutrition: Guidance from the American Academy of Allergy, Asthma, and Immunology; American College of Allergy, Asthma, and Immunology; and the Canadian Society for Allergy and Clinical Immunology

Recently published data from high-impact randomized controlled trials indicate the strong potential of strategies to prevent the development of food allergy in high-risk individuals, but guidance in the United States at present is limited to a policy for only the prevention of peanut allergy, despite other data being available and several other countries advocating early egg and peanut introduction. Eczema is considered the highest risk factor for developing IgE-mediated food allergy, but children without risk factors still develop food allergy. To prevent peanut and/or egg allergy, both peanut and egg should be introduced around 6 months of life, but not before 4 months. Screening before introduction is not required, but may be preferred by some families. Other allergens should be introduced around this time as well. Upon introducing complementary foods, infants should be fed a diverse diet, because this may help foster prevention of food allergy. There is no protective benefit from the use of hydrolyzed formula in the first year of life against food allergy or food sensitization. Maternal exclusion of common allergens during pregnancy and/or lactation as a means to prevent food allergy is not recommended. Although exclusive breast-feeding is universally recommended for all mothers, there is no specific association between exclusive breast-feeding and the primary prevention of any specific food allergy.

Predictors of a positive oral food challenge to cow's milk in children sensitized to cow's milk

INTRODUCTION AND OBJECTIVES

The diagnosis of IgE-mediated cow's milk allergy (CMA) is often based on clinical history and on specific IgE levels and/or skin-prick tests (SPT), both of which are sensitive but not specific. The gold standard, oral food challenge (OFC), is expensive and time-consuming and involves a risk of severe allergic reactions. This study aimed to determine the value of specific IgEs, ratios of specific IgEs for cow's milk and its components to total IgE, and wheal size on SPT for predicting a positive OFC for CMA.

MATERIAL AND METHODS

We retrospectively studied 72 patients [median age, four years; age range 0.75-15 years] sensitized to cow's milk who underwent OFCs to milk. predictive variables between patients with positive and negative OFCs were compared. Receiver operator characteristic (ROC) curves were uses to assess variables' discriminatory capacity and Youden's index to determine the best cut-offs for predicting CMA.

RESULTS

The OFC was positive in 39 (54%) patients. Wheal size on SPT and all specific IgEs and specific-to-total IgE ratios were significantly different between patients with positive OFCs and those with negative OFCs (p<0.001). The variable with the greatest area under the ROC curve was casein-specific IgE (0.98), followed by β-lactoglobulin-specific IgE (0.923), casein-specific-to-total-IgE ratio (0.919), and α-lactalbumin-specific IgE (0.908). Casein-specific IgE ≥0.95kU/L yielded 88.9% sensitivity and 90.9% specificity.

CONCLUSIONS

In our center, casein-specific IgE >0.95kU/L can obviate an OFC to cow's milk for the diagnosis of CMA in patients sensitized to cow's milk with a compatible history.

Pros and cons of pre-emptive screening programmes before peanut introduction in infancy

Peanut allergy is an important public health concern and causes substantial psychosocial comorbidity. Although fatal anaphylaxis is rare (occurring at 0·03-0·3 per million person-years in the general population), peanuts are one of the most frequent causes of food allergy mortality. The Learning Early About Peanut study transformed prevention of peanut allergy by showing that early introduction of peanut into the diet of children at high risk (ie, those with an egg allergy or severe eczema) reduced the relative risk of peanut allergy at age 5 years by 81%. Following publication of this study, the US National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, convened an expert panel, which recommended that, for infants with severe eczema or egg allergy, health professionals should strongly consider evaluation with peanut-specific serological IgE or skin prick test (or both) and, if necessary, an oral food challenge before peanut introduction. In the USA, depending on test results, peanut-containing foods are recommended to be introduced from age 4-6 months in infants with severe eczema or egg allergy. Early introduction to peanuts is also advocated for children with either mild to moderate or no eczema, and in children who are not allergic to egg, but without screening before peanut introduction. However, the NIAID addendum guidelines contrast with other international approaches that do not advocate for allergy screening at a population level before introducing peanuts into infants' diets. In this Review, we evaluate the advantages and disadvantages of a pre-emptive screening approach before the early introduction of peanuts in infants at high risk of peanut allergy.

Eating fish and fruits are associated with lower prevalence of allergic diseases

BACKGROUND

Allergic diseases are recognized as a burden on the public health. They stand as one of the most common chronic diseases, especially in developed countries. Therefore, the objective of this study is to evaluate the association between the development of atopic allergy and the presence of food allergy in children, and food consumption.

METHODS

This multidisciplinary cross-observational epidemiological study was conducted among 1199 schoolchildren who were recruited in 4th grade and 5th grade (9-11 years old from Marseille). Data were collected by means of a standardized epidemiological questionnaire with a medical assessment focusing on allergic diseases, and questions on lifestyle and child nutrition (FFQ).

RESULTS

During the last 12 months, prevalence of allergic diseases were shown as follows: 41% of children presented allergic rhinitis symptoms, 24% reported having asthma related symptoms, while 28% suffered of eczema and 7% complained of food allergy. There was a significant association between food allergy and asthma symptoms (P-value<0.001, IC=[2.29-7.69]), eczema (P-value<0.001, IC=[2.37-8.32]) and allergic rhinitis (P-value<0.001, IC=[2.32-8.17]). Regarding dietary habits, the multivariate analysis shows that the consumption of vegetables (ORa=0.72 [0.64-0.74]) and fish (ORa=0.74 [0.50-1.09], ORa=0.66 [0.47-0.94] respectively) are associated decreased risk of developing asthma and allergic rhinitis symptoms, while fruit consumption (ORa=0.68 [0.45-1.03]) is associated with a decrease in eczema symptoms.

CONCLUSION

This study shows that the presence of a food allergy is strongly associated with allergic diseases. Indeed, the consumption of vegetables, fruits and fish seems to have a protective effect on the occurrence of these diseases.

Peanut Allergy: New Advances and Ongoing Controversies

Peanut allergy is one of the most common food allergies in children, with increasing prevalence over time. The dual-allergen exposure hypothesis now supports transcutaneous sensitization to peanut as a likely pathophysiologic mechanism for peanut allergy development. As a result, there is emerging evidence that early peanut introduction has a role in peanut allergy prevention. Current first-line diagnostic tests for peanut allergy have limited specificity, which may be enhanced with emerging tools such as component-resolved diagnostics. Although management of peanut allergy includes avoidance and carrying an epinephrine autoinjector, risk of fatal anaphylaxis is extremely low, and there is minimal risk related to cutaneous or inhalational exposure. Quality of life in children with peanut allergy requires significant focus. Moving forward, oral and epicutaneous immunotherapy are emerging and exciting tools that may have a role to play in desensitization to peanut.

Intranasal nanoemulsion vaccine confers long-lasting immunomodulation and sustained unresponsiveness in a murine model of milk allergy

BACKGROUND

Immunotherapy for food allergy requires prolonged treatment protocols and, in most cases, does not lead to durable modulation of the allergic immune response. We have demonstrated an intranasal (IN) nanoemulsion adjuvant that redirects allergen-specific Th2 responses toward Th1 and Th17 immunity, and protects from allergen challenge after only 2-4 monthly administrations. Here, we investigate the ability of this technology to provide long-term modulation of allergy in a murine model of cow's milk allergy.

METHODS

Six weeks after sensitization to bovine casein, mice received four, monthly IN immunizations with nanoemulsion formulated with casein. Protection from casein challenge was assessed at 4 and 16 weeks after the final vaccine administration.

RESULTS

The NE vaccine significantly blunted the physiological responses to allergen challenge, and this effect persisted for at least 16 weeks. The protection from challenge was associated with the suppression of casein-specific Th2 immunity and induced Th1 and Th17 cytokines as well as induction of IL-10. Of interest, while immunized animals showed significantly decreased Th2 cytokine responses, cow's milk-specific IgE remained elevated in the serum at levels associated with reactivity in control sensitized animals. Protection was associated with suppressed mast cell activation and markedly reduced mast cell infiltration into the small intestine.

CONCLUSION

The sustained unresponsiveness of at least 16 weeks after vaccination suggests that the nanoemulsion vaccine alters the allergic phenotype in a persistent manner different from traditional desensitization, and this leads to long-term suppressive effects on allergic disease without eliminating serum IgE.

Possible Role of Environmental Factors in the Development of Food Allergies

The development of food allergies is thought to involve multiple factors, and it is unclear which conveys the most risk regarding this process. Since food allergy is a chronic disease without a cure at this time, understanding its development could provide an avenue for preventive practices and development of a curative treatment. Both historical and current data implicate maternal factors, genetics, and environmental exposures as major risk factors in the development of food allergy. An immature gut of the infant has been hypothesized as a possible route of sensitization. Breastfeeding until at least 6 months of age has been shown to have protective factors for the newborn and may possibly improve gut permeability. Newer studies such as the LEAP and EAT investigations also looked at early exposure and prevention of food allergies; their long-term results are critical in understanding early introduction and tolerance. Cutaneous exposure, oral exposure, and food protein exposure in house dust with their relation to the food allergy course are also a path of interest. Current research has shown sensitization can occur through impaired skin such as those with eczema and a filaggrin mutation. Tropomyosin and alpha-gal also are related to the complicated immunomodulatory factors involved in food allergy and allergic response. Cross-reactivity with plant allergens, sensitization to house dust mite and cockroach, and lone star tick bites can also induce food allergens in children and adults. Together, these factors provide a cohesive beginning to understanding how food allergies can occur and can influence further investigation into prevention, treatment, and eventual cure of food allergies.

Food Allergy: A Review

Food allergy is an important public health problem that affects children and adults, and it has been increasing in prevalence in the last 2 to 3 decades. The symptoms can vary from mild to severe, and in extreme cases food allergy can lead to anaphylaxis, which is a life-threatening allergic reaction. Currently, there is no cure for food allergy. Management of food allergy includes allergen avoidance or emergency treatment. The eight most common food allergens are eggs, milk, peanuts, tree nuts, soy, wheat, crustacean shellfish, and fish, all of which are frequently consumed in the US. Thus, patients and their families must remain constantly vigilant, which can often be stressful. Moreover, nonallergic food reactions, such as food intolerance, are commonly mistaken as food allergies. This article highlights risk factors, natural history, diagnosis, and management of food allergy. [Pediatr Ann. 2020;49(1):e50-e58.].

Managing Younger Siblings of Food Allergic Children

Current guidelines state that there is insufficient evidence to recommend testing siblings of food allergic children before introduction of potential allergic foods, but the topic continues to remain controversial. Although the proportion of siblings who are sensitized to a food without clinical reactivity is high in comparison to those with a true food allergy, there is still a known increased risk amongst siblings of children with food allergies that has led to much apprehension about management. The appropriateness of testing and further steps for management of sensitization in the absence of history of clinical reactivity should be discussed with parents.

Allergy and the Pediatric Otolaryngologist

Food allergy and allergic rhinitis are childhood diseases with special relevance to the pediatric otolaryngologist. Much of the diagnosis of food allergy can be made on history alone; strict avoidance is the mainstay treatment. Skin prick testing and serum-specific IgE testing play a stronger role in allergic rhinitis diagnosis. If pharmacotherapy fails, allergen immunotherapy is an option. Currently, there is intense investigation on diagnostic tests, novel treatments, and prevention strategies that could dramatically affect the way these diseases are identified and managed. This article summarizes the epidemiology, pathophysiology, diagnosis, and management of food allergy and allergic rhinitis.

A cross-sectional, population-based study on the prevalence of food allergies among children in two different socio-economic regions of Vietnam

BACKGROUND

There is a paucity of data on the prevalence of food allergy (FA) in Vietnam. A cross-sectional, population-based study was conducted to evaluate the current prevalence of FA among 2- to 6-year-old children in two different regions in Vietnam.

METHOD

A structured, anonymous questionnaire, modified from published FA epidemiologic studies and based on EAACI guidelines, was distributed to parents/guardians of participating children in Hue City (urban area) and Tien Giang Province (rural area). Data collected from the survey were statistically analyzed to generate the prevalence of self-reported and doctor-diagnosed FA and overarching pattern of food allergens.

RESULTS

A total of 8620 responses were collected (response rate 81.5%). Children in Tien Giang reported more than twice the food-induced adverse reactions seen in children in Hue (47.8% vs. 20.5%). In contrast, children in Hue showed higher self-reported FA (9.8%) and doctor-diagnosed FA rates (8.4%) than children in Tien Giang (7.9% and 5.0%, respectively). Crustacean was the predominant allergy-inducing food in both areas (330 of 580 cases, 56.9%), followed by fish, mollusk, beef, milk, and egg. However, substantial variations of FA patterns were seen between the study sites. Geographic location and co-morbidities of other allergic diseases were key risk factors for FA (P < 0.001).

CONCLUSIONS

The prevalence of FA in Vietnamese children seems to be higher than previously reported from other Asian countries. Crustacean is the predominant allergy-inducing food among participating preschool children in Vietnam. The variation of reported food allergen sources across different socio-economic locations could imply different eating habits or the participation of indoor and outdoor allergen exposure.

Analysis of a Large Standardized Food Challenge Data Set to Determine Predictors of Positive Outcome Across Multiple Allergens

Background: Double-blind placebo-controlled food challenges (DBPCFCs) remain the gold standard for the diagnosis of food allergy; however, challenges require significant time and resources and place the patient at an increased risk for severe allergic adverse events. There have been continued efforts to identify alternative diagnostic methods to replace or minimize the need for oral food challenges (OFCs) in the diagnosis of food allergy.

Methods: Data was extracted for all IRB-approved, Stanford-initiated clinical protocols involving standardized screening OFCs to a cumulative dose of 500 mg protein to any of 11 food allergens in participants with elevated skin prick test (SPT) and/or specific IgE (sIgE) values to the challenged food across 7 sites. Baseline population characteristics, biomarkers, and challenge outcomes were analyzed to develop diagnostic criteria predictive of positive OFCs across multiple allergens in our multi-allergic cohorts.

Results: A total of 1247 OFCs completed by 427 participants were analyzed in this cohort. Eighty-five percent of all OFCs had positive challenges. A history of atopic dermatitis and multiple food allergies were significantly associated with a higher risk of positive OFCs. The majority of food-specific SPT, sIgE, and sIgE/total IgE (tIgE) thresholds calculated from cumulative tolerated dose (CTD)-dependent receiver operator curves (ROC) had high discrimination of OFC outcome (area under the curves > 0.75). Participants with values above the thresholds were more likely to have positive challenges.

Conclusions: This is the first study, to our knowledge, to not only adjust for tolerated allergen dose in predicting OFC outcome, but to also use this method to establish biomarker thresholds. The presented findings suggest that readily obtainable biomarker values and patient demographics may be of use in the prediction of OFC outcome and food allergy. In the subset of patients with SPT or sIgE values above the thresholds, values appear highly predictive of a positive OFC and true food allergy. While these values are relatively high, they may serve as an appropriate substitute for food challenges in clinical and research settings.

Prevalence of Self-Reported Food Allergy in Six Regions of Inner Mongolia, Northern China: A Population-Based Survey

Background

The aim of this study was to determine the prevalence of self-reported food allergy in 6 regions of Inner Mongolia, northern China.

Material/Methods

A random cluster sampling population study using a field questionnaire was distributed to 4714 individuals in 6 regions within Inner Mongolia, northern China; the study included ethnic Mongol minorities and Chinese Han populations. The questionnaire obtained data on ethnicity, age, sex, level of education, income, socioeconomic status, rural versus urban location, medical and family history, and food allergy.

Results

There were 4441 (73.5%) completed questionnaires. The prevalence of self-reported food allergy was 18.0% (15.2% men; 20.6% women) and was age-related, being significantly greater in children compared with adults (38.7% vs. 11.9%) (P<0.001). There was a significant difference in self-reported food allergy between rural and urban populations (14.6% vs. 21.4%) (P<0.001) and between Mongolian and Han populations (20.8% vs. 15.8%) (P<0.001). Socioeconomic status, higher education level, and increased family income were significantly correlated with the prevalence of food allergy (P<0.001). Participants with allergic diseases and atopic family history were at increased risk (OR>1, P<0.001). There were no significant associations between the prevalence of food allergy and birth history, infant feeding, and duration of breastfeeding.

Conclusions

An increase in the prevalence of self-reported food allergy was found in the Inner Mongolia region of northern China, which was greater in urban areas compared with rural areas.

The Genetics of Food Allergy

PURPOSE OF REVIEW

Food allergy likely arises from a complex interplay between environmental triggers and genetic susceptibility. Here, we review recent studies that have investigated the genetic pathways and mechanisms that may contribute to the pathogenesis of food allergy.

RECENT FINDINGS

A heritability component of food allergy has been observed in multiple studies. A number of monogenic diseases characterized by food allergy have elucidated pathways that may be important in pathogenesis. Several population-based genetic variants associated with food allergy have also been identified. The genetic mechanisms that play a role in the development of food allergy are heterogeneous and complex. Advances in our understanding of the genetics of food allergy, and how this predisposition interacts with environmental exposures to lead to disease, will improve our understanding of the key pathways leading to food allergy and inform more effective prevention and treatment strategies.

Food allergy: A review and update on epidemiology, pathogenesis, diagnosis, prevention, and management

This review provides general information to serve as a primer for those embarking on understanding food allergy and also details advances and updates in epidemiology, pathogenesis, diagnosis, and treatment that have occurred over the 4 years since our last comprehensive review. Although firm prevalence data are lacking, there is a strong impression that food allergy has increased, and rates as high as approximately 10% have been documented. Genetic, epigenetic, and environmental risk factors are being elucidated increasingly, creating potential for improved prevention and treatment strategies targeted to those at risk. Insights on pathophysiology reveal a complex interplay of the epithelial barrier, mucosal and systemic immune response, route of exposure, and microbiome among other influences resulting in allergy or tolerance. The diagnosis of food allergy is largely reliant on medical history, tests for sensitization, and oral food challenges, but emerging use of component-resolved diagnostics is improving diagnostic accuracy. Additional novel diagnostics, such as basophil activation tests, determination of epitope binding, DNA methylation signatures, and bioinformatics approaches, will further change the landscape. A number of prevention strategies are under investigation, but early introduction of peanut has been advised as a public health measure based on existing data. Management remains largely based on allergen avoidance, but a panoply of promising treatment strategies are in phase 2 and 3 studies, providing immense hope that better treatment will be imminently and widely available, whereas numerous additional promising treatments are in the preclinical and clinical pipeline.

What is new in managing patients with food allergy? Almost everything

PURPOSE OF REVIEW

This review aims to describe current concepts in managing patients with food allergy. There have been many recent advances in the management of patients with IgE-mediated reactions to food, including diagnosis, prevention, management, and ongoing research in the field. Food allergy is increasing in prevalence and may be life threatening. This review aims to highlight changes in recommended practice when diagnosing and managing patients with food allergy.

RECENT FINDINGS

Early introduction of highly allergenic foods, particularly peanut, has been shown to decrease the risk for development of food allergy in patients who are at elevated risk. Avoidance of foods without a clinical history of food allergy may increase the risk of subsequent allergy. Epinephrine remains the first line therapy for anaphylaxis, and patients and families need to be instructed on indications and technique for use. Promising research is ongoing in areas of immunotherapy to food allergens.

SUMMARY

Food allergy is a potentially life-threatening condition that may persist throughout adulthood. Practitioners should be aware of changes to recommendations for the diagnosis, prevention, and management of patients with food allergy.

An update on the impact of food allergy on anxiety and quality of life

PURPOSE OF REVIEW

Food allergies have become more common, and management involves dietary avoidance that can impair quality of life. Patients and families must manage the daily risk of anaphylaxis at each meal. The purpose of this review is to describe the impact of food allergies on quality of life and to provide an update on new developments in food allergy management, particularly peanut allergy.

RECENT FINDINGS

Food allergy requires careful avoidance of common and ubiquitous dietary allergens. Living with food allergy is associated with annual economic costs in excess of $4000 per child, in addition to risks of anxiety and depressive symptoms. An expert panel sponsored by the 2017 National Institute of Allergy and Infectious Diseases published addendum guidelines for the prevention of peanut allergy, which suggest three separate approaches to peanut protein introduction for infants at various levels of risk.

SUMMARY

Clinicians must be aware of underappreciated burdens faced by children and families with food allergies. Management involves a partnership between primary and specialty care. Mitigation strategies to improve quality of life for patients include efforts to avoid overdiagnosis in synergy with balanced counseling about the risks of food allergies. Experimental food allergen desensitization can improve quality of life but remains investigational at this time. For patients with significant anxiety, interdisciplinary management involving professional counseling may be helpful. Risk stratification and early introduction of peanut protein can help prevent the development of peanut allergy.

The Journal of Allergy and Clinical Immunology: In Practice - 2016 Year in Review

As editors, we concluded that it would be helpful to our readers to write a Year in Review article that highlights the Review, Original, and Clinical Communication articles published in 2016 in The Journal of Allergy and Clinical Immunology: In Practice. We summarized articles on the topics of asthma, rhinitis/rhinosinusitis, food allergy, anaphylaxis, drug allergy, urticarial/angioedema, eosinophilic disorders, and immunodeficiency. Within each topic, epidemiologic findings are presented, relevant aspects of prevention are described, and diagnostic and therapeutic advances are enumerated. Diagnostic tools described include history, skin tests, and in vitro tests. Treatments discussed include behavioral therapy, allergen avoidance therapy, positive and negative effects of pharmacologic therapy, and various forms of immunologic and desensitization management. We hope this review will help you, our readers, consolidate and use this extensive and practical knowledge for the benefit of your patients.