Hen's egg allergen in house and bed dust is significantly increased after hen's egg consumption-A pilot study

Skin-centered strategies in food allergy prevention

While the early introduction of food allergens in the infant diet has been shown to be effective at preventing the development of food allergy (FA), its implementation in real life has been associated with various challenges. Interventions aimed at correcting skin barrier dysfunction have been explored in recent decades as a distinct or complementary mean to prevent allergic sensitization through the skin and subsequent development of FA. Studies assessing the application of emollient from birth have yielded conflicting results, and meta-analyses have demonstrated either no effect or only a slight positive effect on FA prevention. However, a careful review of the clinical trials reveals that different emollients were used, which may have explained some of the discrepancies between study results. Emollient application protocols also varied widely between studies. While firm conclusions cannot be drawn with regard to their overall efficacy at preventing FA, the available data provide valuable insight into the characteristics that could be associated with a more effective intervention. Namely, successful trials tended to use emollients with an acidic pH of 5.5, applied over the entire body, and combined with topical corticosteroids in affected areas. Consensus on the optimal strategy to restore skin barrier function could help improve the homogeneity and clinical relevance of future trials on this topic. In the meantime, clinicians should avoid products associated with worse outcomes.

[Oral allergy syndrome (OAS)]

The pollen-food allergy syndrome, also known as oral allergy syndrome, is characterized by local reactions in the mouth and throat after consuming certain raw plant foods in individuals sensitized to pollen from grass, weeds, and trees. Birch-apple is the prototype of this syndrome, with apple, pear, and plum being the most commonly associated foods. Symptoms are usually limited to the oral cavity but can include systemic reactions, including anaphylaxis. Sensitization to pollen allergens, such as lipid transfer proteins, profilin, and PR-10 proteins, triggers this syndrome. Its prevalence varies by geographic region and the predominant pollen type, affecting between 30% and 60% of food allergies. Diagnosis involves a clinical history, skin tests, and, in ambiguous cases, double-blind, placebo-controlled oral food challenges. Treatment primarily involves avoiding trigger foods.

[Food allergy and environmental contamination]

The interaction between genetic potential and the environment, especially increased urbanization and inadequate waste management, contributes to the manifestation of allergic diseases. Pediatric patients are the most vulnerable, due to the immaturity of the respiratory and immune systems. Prenatal and postnatal exposure to air pollutants, both indoors and outdoors, accelerates or aggravates morbidity and mortality from allergic diseases. The "exposome," which encompasses all environmental exposures throughout life, influences health. Biological and chemical attacks alter the epithelial barrier, triggering inflammatory responses and favoring allergic diseases, such as food allergies. The uncontrolled use of toxic fuels, particulate matter, detergents and other factors contribute to the continuous deterioration of the intestinal epithelial barrier, increasing the risk of allergic diseases. It is important to take urgent action to address these issues and protect the health of the planet.

Tolerance to heated egg in egg allergy: Explanations and implications for prevention and treatment

Hen's egg allergy is the second most frequent food allergy found in children. Allergic symptoms can be caused by raw or heated egg, but a majority of egg-allergic children can tolerate hard-boiled or baked egg. Understanding the reasons for the tolerance towards heated egg provides clues about the molecular mechanisms involved in egg allergy, and the differential allergenicity of heated and baked egg might be exploited to prevent or treat egg allergy. In this review, we therefore discuss (i) why some patients are able to tolerate heated egg; by highlighting the structural changes of egg white (EW) proteins upon heating and their impact on immunoreactivity, as well as patient characteristics, and (ii) to what extent heated or baked EW might be useful for primary prevention strategies or oral immunotherapy. We describe that the level of immunoreactivity towards EW helps to discriminate patients tolerant or reactive to heated or baked egg. Furthermore, the use of heated or baked egg seems effective in primary prevention strategies and might limit adverse reactions. Oral immunotherapy is a promising treatment strategy, but it can sometimes cause significant adverse events. The use of heated or baked egg might limit these, but current literature is insufficient to conclude about its efficacy.

Environmental Exposure to Foods as a Risk Factor for Food Allergy

PURPOSE OF REVIEW

Many factors have been reported to contribute to the development of food allergy. Here, we summarize the role of environmental exposure to foods as a major risk factor for developing food allergy.

RECENT FINDINGS

Peanut proteins are detectable and biologically active in household environments, where infants spend a majority of their time, providing an environmental source of allergen exposure. Recent evidence from clinical studies and mouse models suggests both the airway and skin are routes of exposure that lead to peanut sensitization. Environmental exposure to peanut has been clearly associated with the development of peanut allergy, although other factors such as genetic predisposition, microbial exposures, and timing of oral feeding of allergens also likely contribute. Future studies should more comprehensively assess the contributions of each of these factors for a variety of food allergens to provide more clear targets for prevention of food allergy.

Impact of the exposome on food allergy development

PURPOSE OF REVIEW

The increasing global prevalence of food allergy indicates that environmental exposures are likely contributing to food allergy development. This review summarizes recent studies on how specific factors within the external exposome may impact the development of food allergy.

RECENT FINDINGS

There is strong evidence that nonoral exposure to food allergens within the living environment is a risk factor for food sensitization and food allergy. The role of air pollution in food allergy development remains unclear, as cohort studies have not found consistent relationships between air pollutant exposure and food sensitization. Early-life microbial exposures linked to a rural lifestyle are likely protective against food allergy development, possibly through alteration of the infant microbiome. In contrast, factors associated with urbanization and decreased exposure to microbes may contribute to food allergy development. Recent studies on the role of residential greenness in food allergy development suggest either no relationship or a possible increased risk for food allergy.

SUMMARY

The external exposome comprises a number of exposures that can modify food allergy risk. Improved understanding of how complex environmental exposures interact with genetic factors will be necessary for developing effective interventions aimed at preventing food allergy development in children.

Association of egg protein levels in dust with allergy status and related factors

BACKGROUND

Levels of peanut protein in dust have been reported to be associated with sensitization and allergy to it, so controlling food protein in dust may help prevent food allergy. However, studies of factors associated with egg protein levels in dust are scarce. This study aimed to determine the factors contributing to egg protein levels in dust.

METHODS

This cross-sectional study included 159 participants in the Sub-Cohort Study of the Japan Environment and Children's Study in Yamanashi Prefecture at a 6 year follow up. House dust at 6 years was collected and egg protein concentrations were measured for whole egg protein. Household factors, including the maternal frequency of egg consumption, were assessed by questionnaires. A linear regression model was used to analyze the effect of household environmental factors on egg protein in dust.

RESULTS

In multivariate analysis, frequent maternal egg consumption (≥5 times a week) was associated with higher egg protein concentrations in house dust (β = 0.96, P = 0.01). The egg protein load was significantly associated with a higher number of cohabitants (≥5, β = 0.85, P = 0.02) in addition to frequent maternal egg consumption. Among the participants, 140 (88.1%) had no egg allergy, 15 (9.4%) were egg tolerant, and 4 (2.5%) had an egg allergy at 6 years old. There was no significant association between the current egg allergy status and egg protein concentrations in dust.

CONCLUSIONS

The frequency of maternal egg consumption and the number of inhabitants are contributing factors to egg protein levels in dust.

Primary Prevention of Food Allergy-Environmental Protection beyond Diet

A food allergy is a potentially life-threatening disease with a genetic and environmental background. As its prevalence has increased significantly in recent years, the need for its effective prevention has been emphasized. The role of diet modifications and nutrients in food allergy reduction has been extensively studied. Much less is known about the role of other environmental factors, which can influence the incidence of this disease. Changes in neonates gut microbiome by delivery mode, animal contact, inhalant allergens, oral and then cutaneous allergen exposure, air pollution, smoking, infections and vaccinations can be the potential modifiers of food allergy development. There is some data about their role as the risk or preventive factors, but yet the results are not entirely consistent. In this paper we present the current knowledge about their possible role in primary prevention of food allergies. We discuss the mechanisms of action, difficulties in designing accurate studies about food allergy and the potential biases in interpreting the connection between environmental factors and food allergy prevention. A better understanding of the role of environmental factors in food allergies development may help in implementing practical solutions for food allergy primary prevention in the future.

The airway as a route of sensitization to peanut: An update to the dual allergen exposure hypothesis

Food allergies have increased at an alarming rate over the past 2 decades, indicating that environmental factors are driving disease progression. It has been postulated that sensitization to foods, in particular, peanut, occurs through impaired skin. Peanut allergens have been quantified in household dust and may be the culprit source. Indeed, T_H2 cell-skewing innate cytokines can be driven by application of food antigens on both intact and impaired skin of mice, resulting in antigen-specific IgE production and anaphylaxis following allergen exposure. However, allergy induction through the skin can be prevented by induction of oral tolerance before skin exposure. These observations led to the dual allergen exposure hypothesis, according to which oral exposure to food antigens leads to tolerance and antigen exposure on impaired skin leads to allergy. Here, we propose the airway as an alternative route of sensitization in the dual allergen exposure hypothesis that leads to food allergy. Specifically, we will provide evidence from mouse models and human cell-based studies that together implicate the airway as a plausible route of sensitization.

Sensitization to peanut, egg or pets is associated with skin barrier dysfunction in children with atopic dermatitis

BACKGROUND

Children with atopic dermatitis (AD) are often sensitized to food and aeroallergens, but sensitization patterns have not been analysed with biologic measures of disease pathogenicity.

OBJECTIVE

We sought to define allergen sensitization grouping(s) using unbiased machine learning and determine their associations with skin filaggrin (FLG) and transepidermal water loss (TEWL) (assesses skin barrier integrity), S100A8 and S100A9 expression (assesses skin inflammation) and AD severity.

METHODS

We studied 400 children with AD in the Mechanisms of Progression from Atopic Dermatitis to Asthma in Children (MPAACH) cohort to identify groupings of food and aeroallergen sensitizations. MPAACH is a paediatric AD cohort, aged 1-2, recruited through hospital/community settings between 2016 and 2018. We analysed these groupings' associations with AD biomarkers: skin FLG, S100A8 and S100A9 expression, total IgE, TEWL and AD severity.

RESULTS

An unbiased machine learning approach revealed five allergen clusters. The most common cluster (N = 131), SPT_PEP, had sensitization to peanut, egg and/or pets. Three low prevalence clusters, which included children with allergen sensitization other than peanut, egg or pets, were combined into SPT_Other . SPT_NEG included children with no sensitization(s). SPT_PEP children had higher median non-lesional TEWL (16.9 g/m² /h) and IgE (90 kU/L) compared with SPT_OTHER (8.8 g/m² /h and 24 kU/L; p = .01 and p < .001) and SPT_NEG (9 g/m² /h and 26 kU/L; p = .003 and p < .001). SPT_PEP children had lower median lesional (0.70) and non-lesional (1.09) FLG expression compared with SPT_OTHER (lesional: 0.9; p = .047, non-lesional: 1.78; p = .01) and SPT_NEG (lesional: 1.47; p < .001, non-lesional: 2.21; p < .001). There were no differences among groupings in S100A8 or S100A9 expression.

CONCLUSIONS AND CLINICAL RELEVANCE

In this largely clinic-based cohort of young children with AD, allergic sensitization to peanut, egg, cat or dog was associated with more severe disease and skin barrier function but not markers of cutaneous inflammation. These data need replicating in a population-based cohort but may have important implications for understanding the interaction between AD and allergic sensitization.

The External Exposome and Food Allergy

PURPOSE OF REVIEW

The recent increase in childhood food allergy prevalence strongly suggests that environmental exposures are contributing to food allergy development. This review summarizes current knowledge about the role of the external exposome in food allergy.

RECENT FINDINGS

There is growing evidence that environmental exposure to food antigens in house dust through non-oral routes contributes to food sensitization and allergy. Co-exposure to environmental adjuvants in house dust, such as microbial products and fungal allergens, may also facilitate allergic sensitization. While a high-microbe environment is associated with decreased atopy, studies are mixed on whether endotoxin exposure protects against food sensitization. Several chemicals and air pollutants have been associated with food sensitization, but their role in food allergy remains understudied. Children are exposed to numerous environmental agents that can influence food allergy risk. Further studies are needed to identify the key early-life exposures that promote or inhibit food allergy development.

Recent developments and advances in atopic dermatitis and food allergy

This review highlights recent advances in atopic dermatitis (AD) and food allergy (FA), particularly on molecular mechanisms and disease endotypes, recent developments in global strategies for the management of patients, pipeline for future treatments, primary and secondary prevention and psychosocial aspects. During the recent years, there has been major advances in personalized/precision medicine linked to better understanding of disease pathophysiology and precision treatment options of AD. A greater understanding of the molecular and cellular mechanisms of AD through substantial progress in epidemiology, genetics, skin immunology and psychological aspects resulted in advancements in the precision management of AD. However, the implementation of precision medicine in the management of AD still requires the validation of reliable biomarkers, which will provide more tailored management, starting from prevention strategies towards targeted therapies for more severe diseases. Cutaneous exposure to food via defective barriers is an important route of sensitization to food allergens. Studies on the role of the skin barrier genes demonstrated their association with the development of IgE-mediated FA, and suggest novel prevention and treatment strategies for type 2 diseases in general because of their link to barrier defects not only in AD and FA, but also in asthma, chronic rhinosinusitis, allergic rhinitis and inflammatory bowel disease. The development of more accurate diagnostic tools, biomarkers for early prediction, and innovative solutions require a better understanding of molecular mechanisms and the pathophysiology of FA. Based on these developments, this review provides an overview of novel developments and advances in AD and FA, which are reported particularly during the last two years.

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.

Environmental Food Exposure: What Is the Risk of Clinical Reactivity From Cross-Contact and What Is the Risk of Sensitization

For food-allergic individuals, the typical exposure to food proteins happens during ingestion; however, individuals may be exposed to foods in other ways. In addition to ingestion reactions, allergic patients may have reactions from cutaneous or mucosal exposures to food proteins, with the classic example being a peanut-allergic child touching a counter with peanut butter and then rubbing their eyes. Similar to hands, saliva can also act as a carrier for food proteins. Finally, there is a wealth of new research regarding the presence of food proteins in the environment, for example, within household floor dust. This review will focus on (1) cross-contact of food proteins and (2) environmental food protein exposures. Cross-contact occurs when one type of food comes into contact with another type of food resulting in the mixture of proteins. For food allergies, cross-contact is important when an allergen is inadvertently transferred to a food/meal that is thought to not contain that specific allergen. We will discuss the current literature regarding the presence of detectable food proteins in different locations, how and if these proteins are transferred or eliminated, and the clinical implications of exposures to food proteins under these different scenarios.