Which infants with eczema are at risk of food allergy? Results from a population-based cohort

Standardizing the skin tape stripping method for sensitization and using it to create a mouse model of peanut allergy

BACKGROUND

Animal models for food allergies serve as crucial tools in understanding allergy mechanisms and assessing the efficacy of potential desensitization methods. The effectiveness of inducing allergies in mice through intragastric lavage sensitization varies. The intraperitoneal method can trigger systemic anaphylaxis, however it lacks anatomical relevance. Hence, a uniform and reliable allergy induction method in mice is required. Tape -stripping can mimic atopic dermatitis (AD), a precursor to lifelong peanut allergies in humans. Furthermore, skin damage triggers the upregulation of skin alarmins and the expansion of small-intestinal mast cells, both implicated in allergy development.

METHODS

We standardized a skin-based sensitization method in a mouse model of peanut allergy using skin tape-stripping followed by allergen application. We compared this method with intragastric sensitization.

RESULTS

Skin-based sensitization led to increased mast cells, goblet cells, and eosinophils in the small intestine, elevated systemic IgE levels, murine mast cell protease-1 (mMCP-1), histamine, and eosinophilic activity in peripheral blood. Moreover, it resulted in a significant hypothermic response, with nearly 30% mortality following an oral challenge one-month post-sensitization.

CONCLUSION

Our research offers a standardized and readily reproducible method for inducing peanut allergy in mice, which could also be adapted for other food allergens.

The potential of orally exposed risk factors and constituents aggravating food allergy: Possible mechanism and target cells

Food allergy is a significant concern for the health of humans worldwide. In addition to dietary exposure of food allergens, genetic and environmental factors also play an important role in the development of food allergy. However, only the tip of the iceberg of risk factors in food allergy has been identified. The importance of food allergy caused by orally exposed risk factors and constituents, including veterinary drugs, pesticides, processed foods/derivatives, nanoparticles, microplastics, pathogens, toxins, food additives, dietary intake of salt/sugar/total fat, vitamin D, and therapeutic drugs, are highlighted and discussed in this review. Moreover, the epithelial barrier hypothesis, which is closely associated with the occurrence of food allergy, is also introduced. Additionally, several orally exposed risk factors and constituents that have been reported to disrupt the epithelial barrier are elucidated. Finally, the possible mechanisms and key immune cells of orally exposed risk factors and constituents in aggravating food allergy are overviewed. Further work should be conducted to define the specific mechanism by which these risk factors and constituents are driving food allergy, which will be of central importance to the targeted therapy of food allergy.

Sensory sentinels: Neuroimmune detection and food allergy

Food allergy is classically characterized by an inappropriate type-2 immune response to allergenic food antigens. However, how allergens are detected and how that detection leads to the initiation of allergic immunity is poorly understood. In addition to the gastrointestinal tract, the barrier epithelium of the skin may also act as a site of food allergen sensitization. These barrier epithelia are densely innervated by sensory neurons, which respond to diverse physical environmental stimuli. Recent findings suggest that sensory neurons can directly detect a broad array of immunogens, including allergens, triggering sensory responses and the release of neuropeptides that influence immune cell function. Reciprocally, immune mediators modulate the activation or responsiveness of sensory neurons, forming neuroimmune feedback loops that may impact allergic immune responses. By utilizing cutaneous allergen exposure as a model, this review explores the pivotal role of sensory neurons in allergen detection and their dynamic bidirectional communication with the immune system, which ultimately orchestrates the type-2 immune response. Furthermore, it sheds light on how peripheral signals are integrated within the central nervous system to coordinate hallmark features of allergic reactions. Drawing from this emerging evidence, we propose that atopy arises from a dysregulated neuroimmune circuit.

Mechanisms for initiation of food allergy by skin pre-disposed to atopic dermatitis

Food allergy can be life-threatening and often develops early in life. In infants and children, loss-of-function mutations in skin barrier genes associate with food allergy. In a mouse model with skin barrier mutations (Flakey Tail, FT+/- mice), topical epicutaneous sensitization to a food allergen peanut extract (PNE), an environmental allergen Alternaria alternata (Alt) and a detergent induce food allergy and then an oral PNE-challenge induces anaphylaxis. Exposures to these allergens and detergents can occur for infants and children in a household setting. From the clinical and preclinical studies of neonates and children with skin barrier mutations, early oral exposure to allergenic foods before skin sensitization may induce tolerance to food allergens and thus protect against development of food allergy. In the FT+/- mice, oral food allergen prior to skin sensitization induce tolerance to food allergens. However, when the skin of FT+/- pups are exposed to a ubiquitous environmental allergen at the time of oral consumption of food allergens, this blocks the induction of tolerance to the food allergen and the mice can then be skin sensitized with the food allergen. The development of food allergy in neonatal FT+/- mice is mediated by altered skin responses to allergens with increases in skin expression of interleukin 33, oncostatin M and amphiregulin. The development of neonate food allergy is enhanced when born to an allergic mother, but it is inhibited by maternal supplementation with α-tocopherol. Moreover, preclinical studies suggest that food allergen skin sensitization can occur before manifestation of clinical features of atopic dermatitis. Thus, these parameters may impact design of clinical studies for food allergy, when stratifying individuals by loss of skin barrier function or maternal atopy before offspring development of atopic dermatitis.

Sociodemographic factors linked to food allergy diagnosis among high-risk children with atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a known risk factor for the development of food allergy (FA). Prior work has suggested disparities in diagnosis/management of FA in urban populations.

OBJECTIVE

To determine whether socioeconomic conditions, as measured by the area deprivation index and insurance status, or racial/ethnic self-identity was associated with risk of FA diagnosis (DFA), evaluation by an allergist, or objective FA testing among high-risk children with AD.

METHODS

This is a retrospective cohort study of pediatric patients with physician-diagnosed AD who had received primary care at a single urban academic tertiary care center between 2009 and 2022. Statistical analysis in SPSS (IBM Corp. Released 2017. IBM SPSS Statistics for Windows, Version 25.0, Armonk, NY) used χ2, analysis of variance, and logistic regression.

RESULTS

In a total of 3365 pediatric subjects, 41.3% identified as non-Hispanic Black, 33.9% Hispanic, 6.9% Asian, and 14.9% non-Hispanic White. Hispanic children with AD and DFA were significantly less likely to be evaluated by an allergist than White or Asian children (65.9% vs 82.8% and 80.3%, P = .001 and P = .02). Non-Hispanic Black children with AD and DFA were more likely to have no objective FA testing than White children (20.9% vs 12.1%, P = .04). The White and Asian children were more likely to undergo the thorough combination of both blood and skin testing for DFA than Black or Hispanic children (15.5% and 22.4% vs 7.1% and 7.9%, respectively, P = .007, P = .00005, P = .03, P = .0008).

CONCLUSION

Labeling at-risk young children with FA without thorough objective testing can affect their nutrition and quality of life. Barriers to equitable evaluation of DFA should be further investigated and addressed.

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.

Atopic dermatitis and food allergy: More than sensitization

The increased risk of food allergy in infants with atopic dermatitis (AD) has long been recognized; an epidemiologic phenomenon termed "the atopic march." Current literature supports the hypothesis that food antigen exposure through the disrupted skin barrier in AD leads to food antigen-specific immunoglobulin E production and food sensitization. However, there is growing evidence that inflammation in the skin drives intestinal remodeling via circulating inflammatory signals, microbiome alterations, metabolites, and the nervous system. We explore how this skin-gut axis helps to explain the link between AD and food allergy beyond sensitization.

Management of Infant Atopic Eczema to Prevent Severe Eczema and Food Allergy

Early intervention and active management of infant atopic eczema may play a crucial role in limiting eczema severity and preventing the onset of immediate-type food allergy. Eczema management involves education, skincare and medications targeting skin inflammation and barrier repair. Topical corticosteroids are the mainstay of anti-inflammatory therapy, with nonsteroidal options available for some infants. Proactive therapy, addressing subclinical inflammation, is useful for preventing eczema flares, especially in infants with recurrent eczema flares despite reactive therapy. In clinical practice, holistic consideration of overall infant and family health is essential. Providing advice on maternal stress management, nutritional guidance and recommendations for proper sleep and lifestyle is crucial for the well-being of children and their families, not limited to eczema treatment alone.

Serologic measurements for peanut allergy: Predicting clinical severity is complex

Allergist-immunologists use serologic peanut allergy testing to maximize test sensitivity and specificity while minimizing cost and inconvenience. Recent advances toward this goal include a better understanding of specific IgE (sIgE) and component testing, epitope-sIgE assays, and basophil activation testing. Predicting reaction severity with serologic testing is challenged by a range of co-factors that influence reaction severity, such as the amount and form of any allergen consumed and comorbid disease. In 2020, the Allergy Immunology Joint Task Force on Practice Parameters recommended Ara h 2-sIgE as the most cost-effective diagnostic test for peanut allergy because of its superior performance, when compared with skin prick testing and serum IgE. Basophil activation testing, a functional test of allergic response not evaluated in the Joint Task Force on Practice Parameters guideline, is a promising option for both allergy diagnosis and prognosis. Similarly, epitope-sIgE testing may improve prediction of reaction thresholds, but further validation is needed. Despite advances in food allergy testing, many of these tools remain limited by cost, accessibility, and feasibility. In addition, there is a need for further research on how atopic dermatitis may be modifying serologic food allergy severity assessments. Given these limitations, allergy test selection requires a shared decision-making approach so that a patient's values and preferences regarding financial impact, inconvenience, and psychological effects are considered in the context of clinician expertise on the timing and use of optimized testing.

Constant vigilance! Managing threats to the skin barrier

OBJECTIVE

Skin barrier defects are one of the primary causes of atopic dermatitis (AD). The basis of skin barrier defects in AD is due to a deficiency in various barrier proteins including filaggrin, involucrin, claudins, and lipids such as ceramide, fatty acids, and cholesterol. This review updates a more detailed lipid dysregulation in the skin barrier of AD based on recent lipidomic analysis. The clinical implications, treatments, prevention, and predictive capability of skin barrier defects are also reviewed.

DATA SOURCES

Published literature obtained through PubMed searches.

STUDY SELECTIONS

Studies relevant to the mechanisms, clinical implications, treatments, prevention, and predictors of AD development.

RESULTS

Skin barrier defects contribute to transepidermal water loss, infections, IgE sensitizations, and cutaneous inflammation in AD. Preventive treatments include daily hydration and application of moisturizers. Because skin barrier defects precede the development of AD, they provide an opportunity for prediction and intervention.

CONCLUSION

Skin barrier defects play an important role in the comorbidities of AD including infectious complications, disease flare, and allergic diathesis. Current research focuses on prevention and prediction of AD development.

Feasibility and Safety of the Early Introduction of Allergenic Foods in Asian Infants with Eczema

BACKGROUND

There is a lack of data regarding the early introduction of the consumption of allergenic food among Asian infants.

METHODS

We examined infants who had early-onset eczema before 6 months of age and received instructions from certified allergists for the early introduction of hen's eggs, milk, wheat, peanuts, and tree nuts.

RESULTS

The consumption rates of hen's eggs were 100% at 24 months. For peanuts and walnuts, the consumption rate was moderate at 12 months (48.5% and 30.3%, respectively), but by 24 months, it had progressed to 78.8% and 81.3%, respectively. In contrast, cashews remained at lower levels than other allergens at 20.7% at 12 months and 41.4% at 24 months. No adverse events related to early introductions occurred.

CONCLUSIONS

In infants with eczema, allergenic foods could be introduced early and well tolerated in Asian infants. However, having eczema may indicate a predisposition to food allergies, so caution is necessary when introducing allergenic foods. The early introduction of peanuts and tree nuts was still more challenging in real-world practice in Asia as well as in Western countries.

Metabolomics in Children Cow's Milk Protein Allergy: Possible Contribution from a System Biology Approach?

One of the most frequent triggers of food anaphylaxis in pediatric age but also among the most common, early, and complex causes of childhood food allergy is cow's milk protein allergy (CMPA). The diagnostic course and management of this allergy is defined in a complex clinical picture due to several factors. First of all, the epidemiological data are not uniform, mainly as a consequence of the diagnostic methodology used in the various studies and the different age ranges covered. In addition, there is the complexity of terminology, since although CMPA traditionally refers to immune-mediated reactions to cow's milk, it is a term encompassing numerous clinical features with different symptoms and the requirement for specific treatments. Moreover, the differential diagnosis with other very frequent diseases, especially in the first year of life, such as gastro-esophageal reflux disease or colic, is still complex. This can result in misdiagnosis and incorrect treatment, with harmful health consequences and significant economic repercussions. In this context, the combination of several omics sciences together, which have already proved useful in clarifying the allergenicity of cow's milk proteins with greater precision, could improve the diagnostic tests currently in use through the identification of new, more specific, and precise biomarkers that make it possible to improve diagnostic accuracy and predict the patient's response to the various available treatments for the recovery of tolerance.

Predictive modeling for cow's milk allergy remission by low-dose oral immunotherapy in young children

Background

The effectiveness of slow low-dose oral immunotherapy (SLOIT) for cow's milk (CM) allergy has been reported. Most OIT studies have discussed the target populations over 4 years old. Furthermore, no predicting modeling is reported for CM allergy remission by CM-SLOIT under 4 years of age.

Objective

We sought to develop a predictive model for CM allergy remission by SLOIT after 3 years in young children who started CM-SLOIT under 4 years of age.

Methods

We included young children with cow's milk allergy or cow's milk sensitization (development modeling set with 120 children and validation modeling set with 71 children). We did logistic regression analysis to develop the models. We calculated the area under the receiver operating curves (ROC-AUCs) to evaluate the predictive modeling performance.

Results

The model (CM-sIgE before SLOIT + age at beginning SLOIT + serum TARC before starting SLOIT + CM-sIgE titer one year after OIT) showed good discrimination with the ROC-AUC of 0.83 (95% CI:0.76-0.91) on internal validation. Applying the model to the validation set gave good discrimination (ROC-AUC = 0.89, 95% CI:0.80-0.97) and a reasonable calibration (intraclass correlation coefficient = 0.88, 95% CI:0.62-0.97).

Conclusion

We developed and validated predictive modeling for determining the remission rate of CM allergy at 3 years after SLOIT under 4 years of age in children with CM allergy. This predictive model is highly accurate and can support CM allergy management. (226 words).

Schwere atopische Dermatitis im frühen Kindesalter: Besonderheiten, Herausforderungen und neue Perspektiven in der Versorgung

Die atopische Dermatitis ist die häufigste chronische Hauterkrankung im Kindesalter mit einer Prävalenz von 10% bei Kleinkindern unter 2 Jahren, wovon etwa 15% einen hohen Schweregrad aufweisen. „Kinder sind keine kleinen Erwachsenen“, dies trifft für die schwere frühkindliche atopische Dermatitis in besonderem Maße zu. Innerhalb dieser sensiblen Lebensphase zeigen sich alterstypische Facetten der Erkrankung (psychosozial, neurokognitiv, klinisch‐morphologisch), die Unterschiede im Management mit sich bringen.

Besondere Bedeutung hat die Identifikation von Säuglingen und Kleinkindern mit früh‐persistierendem, schwerem Verlauf mit Blick auf eine erstmals für diese Altersgruppe zugelassene Systemtherapie: sowohl für die unmittelbare Versorgung der Hauterkrankung als auch unter dem Aspekt einer möglichen Prävention von Begleiterkrankungen. Da der „atopische Phänotyp“ klinische Überlappungen zum Spektrum der Immundefekte aufweist, ist die korrekte Einordnung des Hautbefundes bei therapierefraktärem Ekzem essenziell. In dieser Arbeit beschreiben wir eine alltagstaugliche Strategie, um anhand anamnestischer Warnhinweise, dermatologischer Leitbefunde und Labordiagnostik eine Abgrenzung von ekzematösen Hauterscheinungen bei primären Immundefekten vorzunehmen. Dazu geben wir aktuelle Empfehlungen zum Management des schweren frühkindlichen atopischen Ekzems, auch in Bezug auf die Indikation zur Systemtherapie.

Severe atopic dermatitis in early infancy: characteristics, challenges and new perspectives in clinical practice

Atopic dermatitis (AD) is the most common skin disease in infants and children with a prevalence of 10% in the first two years of life. In this age group up to 15% are severely affected. "Children are not little adults" - this applies in particular to infants with severe atopic dermatitis. Age-specific clinical aspects (psychosocial, neurocognitive, morphological) of the disease require an adjusted disease management. Considering recent approval of systemic treatment options, early identification of infants and children with severe and early persistent disease is of particular importance also in view of possible prevention of atopic comorbidity. As several inborn errors of immunity (IEI) share features of the atopic phenotype, it is essential for clinicians to distinguish signs of immunodeficiency from severe AD. Here, we describe a practical approach on the basis of clinical history and key dermatological and laboratory findings. Furthermore, this paper is aimed at providing an update on general management of severe AD in early infancy, including recommendations for systemic treatment.

Optimising the management of peanut allergy by targeting immune plasticity

Randomised controlled trials investigating the efficacy of oral tolerance induction to peanut have enabled detailed comparison of their clinical and immunological success. They have demonstrated that the regular consumption of peanut for at least 2 years by babies who are not allergic enables protection from developing peanut allergy. The LEAP study intervention tested the impact of regular peanut consumption for 4 years and demonstrated a sustained protection against the development of peanut allergy even after 12 months of peanut avoidance from 5 to 6 years of age. The PreventADALL trial introduced multiple allergens into babies' diets from early infancy and reduced the prevalence of food allergy at 3 years, especially by protecting against peanut allergy. Immunological studies from the LEAP cohort demonstrated that regular peanut consumption was associated with a prompt induction of peanut-specific IgG4 and reduced manufacture of peanut and Ara h 2-specific IgE. Even after stopping peanut consumption for 5 years, there continued to be a significant fall in peanut-specific Ara h 2 IgE in the consumption group from 5 to 6 years of age (p < .01). Children who developed peanut allergy by 5 years started to develop increasing sensitisation to linear sequential peanut epitopes from 2.5 years of age, suggesting that putative disease-modifying interventions should commence before 3 years. Data comparing clinical outcomes between children undergoing peanut immunotherapy from infancy suggest that younger children can consume higher portions of peanut without reaction on challenge whilst taking immunotherapy, have fewer side effects and are more likely to enjoy remission of PA. Peanut oral immunotherapy modulates T-cell populations in order to bring about hypo-responsiveness of allergy effector cells. Studies are now needed to characterise and compare different states of immunological tolerance. This will accelerate the design of interventions which can promote primary, secondary and tertiary levels of PA prevention across a range of age groups.

The clinical burden of food allergies: Insights from the Food Allergy Research & Education (FARE) Patient Registry

Background

Food allergies are serious and potentially life-threatening, and often place a large burden on patients and their caregivers, including impacts on quality of life.

Objective

To assess the real-world patient burden of food allergies, using self-reported data available from the Food Allergy Research & Education (FARE) Patient Registry (NCT04653324).

Methods

The FARE Patient Registry is voluntary and captures real-world experiences of adults and pediatric patients in the United States, and their caregivers, through a series of surveys assessing patient health and experiences with food allergies. Self-reported data were descriptively analyzed.

Results

The FARE study cohort included 5587 patients with food allergies; 82% had multiple food allergies and 62% were aged <18 years. About half of the patients were first diagnosed by an allergist/immunologist (53%), most commonly with a skin prick test (71%) or a serum immunoglobulin E test (62%). This analysis found that food allergies (most commonly peanut [66%], tree nuts [61%], egg [43%], and milk [37%]) impart a large clinical burden on patients, many of whom experience food-related allergic reactions and comorbidities. Many patients experienced >1 food-related allergic reaction per year (42%), with 46% experiencing food-induced anaphylaxis. Half of all food-related allergic reactions occurred at home. Accidental exposures to food allergens were experienced by 77% of patients. The most common allergic comorbidities reported by patients with food allergies were atopic dermatitis (48%), asthma (46%), and allergic rhinitis (39%). The clinical burden of food allergies were found to be greater in patients with multiple food allergies, and different for adults versus pediatric patients.

Conclusion

This is the first study to assess patient experience and disease burden information from patients contributing to the FARE Patient Registry, thus providing a unique insight into the lives of patients in the United States with food allergies. These insights may assist clinicians and other public health stakeholders in the management of patients with food allergies.

Gene-edited pigs: a translational model for human food allergy against alpha-Gal and anaphylaxis

The prevalence of food allergy is rising and is estimated to approach 10%. Red meat allergy is the first known food allergy elicited by immunoglobulin E (IgE) antibodies recognizing a carbohydrate. Due to the loss of function of the alpha-1,3-galactosyltransferase (GGTA1) gene in humans, the disaccharide galactose-α-1,3-galactose (α-Gal) cannot be synthesized and therefore became immunogenic. IgE sensitization is elicited through the skin by repetitive tick bites transmitting α-Gal. The underlying mechanisms regarding innate and adaptive immune cell activation, including the B-cell isotype switch to IgE, are poorly understood, requiring further research and physiologically relevant animal models. Here, we describe a new animal model of red meat allergy using percutaneous α-Gal sensitization of gene-edited GGTA1-deficient pigs. Total and α-Gal-specific IgG, IgG1, IgG2, IgG4, and IgE levels were tracked. Further key factors associated with allergic skin inflammation, type 2 immunity, and allergy development were measured in PBMCs and skin samples. Significant increases in α-Gal-specific IgG1 and IgE levels indicated successful sensitization to the allergen α-Gal. Intracutaneous sensitizations with α-Gal recruited lymphocytes to the skin, including elevated numbers of T helper 2 (Th2) cells. Finally, α-Gal-sensitized pigs not only recognized α-Gal as non-self-antigen following α-Gal exposure through the skin but also developed anaphylaxis upon antigen challenge. Based on the similarities between the porcine and human skin, this new large animal model for α-Gal allergy should help to unveil the consecutive steps of cutaneous sensitization and aid the development of prophylactic and treatment interventions.

Gastrointestinal Comorbidities Associated with Atopic Dermatitis-A Narrative Review

The current understanding of atopic dermatitis (AD) seems to be extending beyond a skin-confined condition frequently associated with allergic comorbidities, as in a number of epidemiological studies, the prevalence rate of a range of illnesses has been determined to be greater in patients with AD, or inversely. In most cases, the reasons for this are vague. A subset of these conditions are gastrointestinal disorders, including food sensitization (FS) and food allergy (FA), eosinophilic esophagitis (EoE) (it is of mixed background, both IgE-dependent and independent), food protein-induced enterocolitis syndrome (FPIES) (it exemplifies an IgE-independent food allergy), Crohn's disease (CD), colitis ulcerosa (CU), celiac disease, irritable bowel syndrome (IBS), and gastroesophageal reflux disease (GERD). In this review, we performed a comprehensive search of the literature using the PubMed database. We addressed the epidemiology of the increased co-occurrence of these diseases with AD and discussed potential causes for this subject. Multiple gastroenterological comorbidities appear to be more common in patients with AD, according to our review. The mechanisms that underlie this phenomenon are largely unknown, highlighting the need for further study in this field.

Directed acyclic graph for epidemiological studies in childhood food allergy: Construction, user's guide, and application

Understanding modifiable prenatal and early life causal determinants of food allergy is important for the prevention of the disease. Randomized clinical trials studying environmental and dietary determinants of food allergy may not always be feasible. Identifying risk/protective factors for early-life food allergy often relies on observational studies, which may be affected by confounding bias. The directed acyclic graph (DAG) is a causal diagram useful to guide causal inference from observational epidemiological research. To date, research on food allergy has made little use of this promising method. We performed a literature review of existing evidence with a systematic search, synthesized 32 known risk/protective factors, and constructed a comprehensive DAG for early-life food allergy development. We present an easy-to-use online tool for researchers to re-construct, amend, and modify the DAG along with a user's guide to minimize confounding bias. We estimated that adjustment strategies in 57% of previous observational studies on modifiable factors of childhood food allergy could be improved if the researchers determined their adjustment sets by DAG. Future researchers who are interested in the causal inference of food allergy development in early life can apply the DAG to identify covariates that should and should not be controlled in observational studies.

Lipidomics and Metabolomics in Infant Atopic Dermatitis: What's the Correlation with Early Nutrition?

To date, the complex picture of atopic dermatitis (AD) has not yet been fully clarified, despite the important prevalence of this disease in the pediatric population (20%) and the possibility of persistence into adulthood, with important implications for the quality of life of those affected, as well as significant social and financial costs. The most recent scientific evidence suggests a new interpretation of AD, highlighting the important role of the environment, particularly that of nutrition in the early stages of development. In fact, the new indications seem to point out the harmful effect of elimination diets, except in rare cases, the uselessness of chrono-insertions during complementary feeding and some benefits, albeit weak, of breastfeeding in those at greater risk. In this context, metabolomics and lipidomics can be necessary for a more in-depth knowledge of the complex metabolic network underlying this pathology. In fact, an alteration of the metabolic contents in children with AD has been highlighted, especially in correlation to the intestinal microbiota. While preliminary lipidomic studies showed the usefulness of a more in-depth knowledge of the alterations of the skin barrier to improve the development of baby skin care products. Therefore, investigating the response of different allergic phenotypes could be useful for better patient management and understanding, thus providing an early intervention on dysbiosis necessary to regulate the immune response from the earliest stages of development.

Understanding food allergy through neuroimmune interactions in the gastrointestinal tract

Food allergies are adverse immune reactions to food proteins in the absence of oral tolerance, and the incidence of allergies to food, including peanut, cow's milk, and shellfish, has been increasing globally. Although advancements have been made toward understanding the contributions of the type 2 immune response to allergic sensitization, crosstalk between these immune cells and neurons of the enteric nervous system is an area of emerging interest in the pathophysiology of food allergy, given the close proximity of neuronal cells of the enteric nervous system and type 2 effector cells, including eosinophils and mast cells. At mucosal sites, such as the gastrointestinal tract, neuroimmune interactions contribute to the sensing and response to danger signals from the epithelial barrier. This communication is bidirectional, as immune cells express receptors for neuropeptides and transmitters, and neurons express cytokine receptors, allowing for the detection of and response to inflammatory insults. In addition, it seems that neuromodulation of immune cells including mast cells, eosinophils, and innate lymphoid cells is critical for amplification of the type 2 allergic immune response. As such, neuroimmune interactions may be critical targets for future food allergy therapies. This review evaluates the contributions of local enteric neuroimmune interactions to the underlying immune response in food allergy and discusses considerations for future investigations into targeting neuroimmune pathways for treatment of food allergies.

Early-life risk factors for food allergy: Dietary and environmental factors revisited

There appears a steep increase in the prevalence of food allergy worldwide in the past few decades. It is believed that, rather than genetic factors, the recently altered dietary and environmental factors are the driving forces behind the rapid increase of this disease. Accumulating evidence has implied that external exposures that occurred in prenatal and postnatal periods could affect the development of oral tolerance in later life. Understanding the potential risk factors for food allergy would greatly benefit the progress of intervention and therapy. In this review, we present updated knowledge on the dietary and environmental risk factors in early life that have been shown to impact the development of food allergy. These predominantly include dietary habits, microbial exposures, allergen exposure routes, environmental pollutants, and so on. The key evidence, conflicts, and potential research topics of each theory are discussed, and associated interventional strategies to prevent the disease development and ameliorate treatment burden are included. Accumulating evidence has supported the causative role of certain dietary and environmental factors in the establishment of oral tolerance in early life, especially the time of introducing allergenic foods, skin barrier function, and microbial exposures. In addition to certain immunomodulatory factors, increasing interest is raised toward modern dietary patterns, where adequately powered studies are required to identify contributions of those modifiable risk factors. This review broadens our understanding of the connections between diet, environment, and early-life immunity, thus benefiting the progress of intervention and therapy of food allergy.

Food Sensitivity in Children Diagnosed with Atopic Dermatitis in The First 2 Years: How Many of These Patients Are Truly Allergic?

Objectives

In this study, it was aimed to examine food sensitivity in patients with atopic dermatitis (AD) and to investigate the frequency of food allergy in patients with food sensitivity.

Methods

Patients aged 0-2 years who were followed up with the diagnosis of AD were included in the study. The characteristics of demographic and clinical and laboratory findings of the patients were recorded retrospectively. Patients were classified as mild, moderate, and severe using the SCORing AD index according to the severity of AD. The presence of food sensitivity was evaluated by skin prick test and serum-specific immunoglobulin (Ig)E results. Food allergy was diagnosed by oral food challenge (OFC) test.

Results

Of the 72 patients included in the study, 62.5% (n=45) were male, and the mean age was 9±4.8 months. When the disease severity was evaluated, it was mild in 40 patients (55.6%); moderate/severe AD was present in 32 patients (44.4%). The frequency of moderate/severe AD was higher in patients who were younger (p=0.01), whose symptoms started in the first 6 months (p=0.03), who had a family history of allergic disease (p=0.001), who breastfed for <6 months (p=0.01), who had a higher median serum total IgE level, and a higher percentage of serum eosinophils (p=0.005 and p=0.01, respectively). Food sensitivity in 45.8% of patients; food allergy was detected in 41.7% of them. The most common sensitivities and allergies were eggs white/yolk and cow's milk, respectively. The rate of food sensitivity was found to be higher in male gender (p=0.03) and breastfed patients (p=0.03), whereas it was similar in patients with mild and moderate/severe AD.

Conclusion

In the investigation of food sensitivity in patients with AD, it is important to evaluate other demographic and clinical characteristics such as gender and breastfeeding, apart from the severity of disease. The OFC test should be performed to confirm the food allergy in patients with food sensitivity before the recommendation of an elimination diet.

The immunological and structural epidermal barrier dysfunction and skin microbiome in atopic dermatitis-an update

Atopic dermatitis (AD) is a common, chronic and relapsing inflammatory skin disease with various clinical presentations and combinations of symptoms. The pathophysiology of AD is complex and multifactorial. There are several factors involved in the etiopathogenesis of AD including structural and immunological epidermal barrier defect, imbalance of the skin microbiome, genetic background and environmental factors. Alterations in structural proteins, lipids, proteases, and their inhibitors, lead to the impairment of the stratum corneum which is associated with the increased skin penetration and transepidermal water loss. The elevated serum immunoglobulin E levels and blood eosinophilia have been shown in the majority of AD patients. Type 2 T-helper cell immune pathway with increased expression of interleukin (IL)-4, IL-5, and IL-13, has an important role in the etiopathogenesis of AD. Both T cells and keratinocytes contribute to epidermal barrier impairment in AD via a dynamic interaction of cytokines and chemokines. The skin microbiome is another factor of relevance in the etiopathogenesis of AD. It has been shown that during AD flares, Staphylococcus aureus (S. aureus) colonization increased, while Staphylococcus epidermidis (S. epidermidis) decreased. On the contrary, S. epidermidis and species of Streptococcus, Corynebacterium and Propionibacterium increased during the remision phases. However, it is not clear whether skin dysbiosis is one of the symptoms or one of the causes of AD. There are several therapeutic options, targeting these pathways which play a critical role in the etiopathogenesis of AD. Although topical steroids are the mainstay of the treatment of AD, new biological therapies including IL-4, IL-13, and IL-31 inhibitors, as well as Janus kinase inhibitors (JAKi), increasingly gain more importance with new advances in the therapy of AD. In this review, we summarize the role of immunological and structural epidermal barrier dysfunction, immune abnormalities, impairment of lipids, filaggrin mutation and skin microbiome in the etiopathogenesis of AD, as well as the therapeutic options for AD and their effects on these abnormalities in AD skin.

The SunBEAm birth cohort: Protocol design

Background

Food allergy (FA) and atopic dermatitis (AD) are common conditions that often present in the first year of life. Identification of underlying mechanisms and environmental determinants of FA and AD is essential to develop and implement effective prevention and treatment strategies. Objectives: We sought to describe the design of the Systems Biology of Early Atopy (SunBEAm) birth cohort.

Methods

Funded by the National Institute of Allergy and Infectious Diseases (NIAID) and administered through the Consortium for Food Allergy Research (CoFAR), SunBEAm is a US population-based, multicenter birth cohort that enrolls pregnant mothers, fathers, and their newborns and follows them to 3 years. Questionnaire and biosampling strategies were developed to apply a systems biology approach to identify environmental, immunologic, and multiomic determinants of AD, FA, and other allergic outcomes.

Results

Enrollment is currently underway. On the basis of an estimated FA prevalence of 6%, the enrollment goal is 2500 infants. AD is defined on the basis of questionnaire and assessment, and FA is defined by an algorithm combining history and testing. Although any FA will be recorded, we focus on the diagnosis of egg, milk, and peanut at 5 months, adding wheat, soy, cashew, hazelnut, walnut, codfish, shrimp, and sesame starting at 12 months. Sampling includes blood, hair, stool, dust, water, tape strips, skin swabs, nasal secretions, nasal swabs, saliva, urine, functional aspects of the skin, and maternal breast milk and vaginal swabs.

Conclusions

The SunBEAm birth cohort will provide a rich repository of data and specimens to interrogate mechanisms and determinants of early allergic outcomes, with an emphasis on FA, AD, and systems biology.

Smoke exposure and childhood atopic eczema and food allergy: A systematic review and meta-analysis

BACKGROUND

There is no consensus on the effect of timing and type of smoke exposure on early allergy development. This study aimed to determine the relationship between early eczema or food allergy/hypersensitivity development in children by firstly investigating the effect of smoke exposure across critical development periods and secondly by analyzing effects of parental atcive or passive smoking.

METHODS

Four databases (PubMed, Web of Science, Scopus and Embase) were searched in May 2022 and assessed by two independent reviewers. Case-control, cross-sectional or cohort studies reporting on smoke exposure from preconception to postnatal periods and atopic eczema, food allergy and/or hypersensitivity outcomes by age 3 years were included. The Newcastle-Ottawa Scale was used to assess study quality. Random effects model was used to estimate the pooled risk ratios.

RESULTS

From 1689 identified records, 32 studies with nearly 190,000 subjects were included. Parental smoking during preconception, pregnancy and postnatal periods was generally not associated with the risk of eczema, food allergy and food sensitisation development by age 3 years. Maternal active smoking during pregnancy was negatively associated with self-reported doctor diagnosis of eczema (RR = 0.87, 95% CI 0.77-0.98; I2  = 50.56) and maternal passive smoking during pregnancy was positively associated with clinician assessment of eczema in one study (RR = 1.38; 95% CI 1.06-1.79).

CONCLUSION

Our findings highlighted the importance of in utero programming in early-life allergy development. Despite the weak evidence, our results suggest pregnant women should minimise their contact with second-hand smoke to prevent offspring eczema development. There is a need for greater utilisation of objective allergy assessments in future studies.

Enhanced early skin treatment for atopic dermatitis in infants reduces food allergy

BACKGROUND

Early-onset atopic dermatitis is a strong risk factor for food allergy, suggesting that early effective treatment may prevent transcutaneous sensitization.

OBJECTIVES

This study tested whether enhanced treatment of atopic dermatitis to clinically affected and unaffected skin is more effective in preventing hen's egg allergy than reactive treatment to clinically affected skin only.

METHODS

This was a multicenter, parallel-group, open-label, assessor-blind, randomized controlled trial (PACI [Prevention of Allergy via Cutaneous Intervention] study). This study enrolled infants 7-13 weeks old with atopic dermatitis and randomly assigned infants in a 1:1 ratio to enhanced early skin treatment or conventional reactive treatment using topical corticosteroids (TCSs). The primary outcome was the proportion of immediate hen's egg allergy confirmed by oral food challenge at 28 weeks of age.

RESULTS

This study enrolled 650 infants and analyzed 640 infants (enhanced [n = 318] or conventional [n = 322] treatment). Enhanced treatment significantly reduced hen's egg allergy compared with the conventional treatment (31.4% vs 41.9%, P = .0028; risk difference: -10.5%, upper bound of a 1-sided CI: -3.0%), while it lowered body weight (mean difference: -422 g, 95% CI: -553 to -292 g) and height (mean difference: -0.8 cm, 95% CI: -1.22 to -0.33 cm) at 28 weeks of age.

CONCLUSIONS

This study highlighted the potential of well-controlled atopic dermatitis management as a component of a hen's egg allergy prevention strategy. The enhanced treatment protocol of this trial should be modified before it can be considered as an approach to prevent hen's egg allergy in daily practice to avoid the adverse effects of TCSs. After remission induction by TCSs, maintenance therapy with lower potency TCSs or other topical therapies might be considered as alternative proactive treatments to overcome the safety concerns of TCSs.

Diseases from the Spectrum of Dermatitis and Eczema: Can "Omics" Sciences Help with Better Systematics and More Accurate Differential Diagnosis?

Researchers active in the field of inflammatory skin diseases from the spectrum of dermatitis and eczema are well aware of a considerable overlap in the clinical pictures and proposed sets of diagnostic criteria for these diseases, which can hardly be overcome through the clinical or epidemiological research. In effect, patients are included in studies based on vague and overlapping criteria, while heterogeneous study populations may, in turn, lead to non-representative outcomes and continued confusion. In this narrative review, a systematics of diseases from the spectrum of dermatitis and eczema is proposed based on the origins of causative factors and the pathomechanisms involved. Difficulties in differentiating between these diseases are discussed, and the extent to which advances in the "omics" sciences might help to overcome them is considered. Of all the "omics" research in this field, more than 90% of the published papers were devoted to atopic dermatitis, with a striking underrepresentation of other diseases from the spectrum of dermatitis and eczema, conditions which collectively exceed the rates of atopic dermatitis by far. A greater "omics" research effort is urgently needed to tackle other dermatitides, like allergic, irritant and protein contact dermatitis, as well as radiation, seborrheic, stasis or autoimmune dermatitis. Atopic dermatitis findings should be validated not only against healthy donors but also other dermatitides. A clinic-oriented approach is proposed for future "omics" studies in the field of dermatitis and eczema.

Recent advances in cellular and molecular mechanisms of IgE-mediated food allergy

Food allergy is a public health issue the prevalence of which is steadily increasing. New discoveries have contributed to the understanding of the molecular and cellular mechanisms that lead to IgE-mediated food allergy. Novel scientific findings have defined roles for specific cell types, such as T follicular helper cells, in induction of high-affinity IgE by B cells. Also, not only mast cells and basophils contribute to food anaphylaxis, but also other cell types, such as neutrophils and macrophages. Elucidation of mechanisms involved in sensitization to food allergens through organs including the skin is key to deepening our understanding of the "dual exposure" hypothesis, which suggests that allergic sensitization is mainly acquired through inflamed skin while the oral route induces tolerance. This review considers the latest scientific knowledge about the molecular and cellular mechanisms of IgE-mediated food allergy. It reveals crucial components involved in the sensitization and elicitation phases and emerging approaches in anaphylaxis pathophysiology.

Pearls and Pitfalls of Weaning an Infant with Severe Atopic Dermatitis and Sensitization/Allergy to Food

Atopic dermatitis (AD) is a common chronic inflammatory skin disorder in childhood. Skin barrier impairment exposes infants to food allergens, potentially causing sensitization followed by IgE-mediated food allergy. We describe the case of an infant with severe AD in whom several sensitizations to foods are detected, with consequently difficult weaning, and a history of anaphylaxis to cashew nut. Foods for which skin tests were negative were introduced into the infant's diet. Then, when AD control was managed, oral food challenges (OFCs) for foods to which the patient was sensitized, with the exception of cashew nut, were performed. The simultaneous presence of sensitization toward multiple foods made it difficult to introduce them using classic OFC. Therefore, it was decided to perform the low-dose, gradual controlled OFC. This led to an introduction of sensitized foods into the infant's diet, with the exception of cashew nut, avoiding allergic reactions. Absolute recommendations on how, when, and where to perform OFCs with allergenic food to which the child with AD is sensitized are lacking so far. In our opinion, OFCs and the subsequent ntroduction of allergenic foods should be individualized, evaluating some factors such as their social and nutritional importance, the patient's age and clinical phenotype (including the history of anaphylaxis), and the sensitization profile. There is agreement on the fact that the dietary approach in children with moderate-severe AD should no longer include a strict elimination diet. We believe that an early, gradual controlled introduction of all allergenics to identify the amount of food tolerated in the absence of reactions, even if low dose, may improve patients' and families' quality of life. However, even if discussing a vast relevant literature, the limitation of our work is that we describe the management of a single patient. Extensive and high-quality research is needed in this field to improve the available evidence in the area.

Association of soap use when bathing 18-month-old infants with the prevalence of allergic diseases at age 3 years: The Japan Environment and Children's Study

BACKGROUND

Atopic march is defined as the progression from atopic dermatitis (AD) during early life to other allergic diseases in later childhood. In a nationwide birth cohort study, the Japan Environment and Children's Study, we investigated the association of bathing habits, which are known to affect skin conditions, for infants with their later development of allergic diseases.

METHODS

Pregnant women who lived in 15 designated regional centers throughout Japan were recruited. We obtained information on bathing habits for their 18-month-old infants and the prevalence of allergic diseases when they were aged 3 years.

RESULTS

Data for 74,349 children were analyzed. Most 18-month-old infants were bathed or showered almost every day. When they were divided into four groups according to the frequency of soap use during bathing (every time, most of the time, sometimes, and seldom), the risk of AD later at age 3 was shown to increase in association with a decreasing frequency of soap use [most of the time: adjusted odds ratio (aOR) 1.18, 95% confidence interval (CI) 1.05-1.34; sometimes: aOR 1.72, 95% CI 1.46-2.03; seldom: aOR 1.99, 95% CI 1.58-2.50], compared with soap use every time during bathing at 18 months of age. Similar results were obtained for food allergy but not for bronchial asthma.

CONCLUSIONS

Frequent soap use when bathing 18-month-old infants was associated with a decreased risk of them developing allergic diseases at age 3. Further well-designed clinical studies are warranted to determine an effective bathing regimen for preventing the development of allergic diseases.

Advances and potential of omics studies for understanding the development of food allergy

The prevalence of food allergy continues to rise globally, carrying with it substantial safety, economic, and emotional burdens. Although preventative strategies do exist, the heterogeneity of allergy trajectories and clinical phenotypes has made it difficult to identify patients who would benefit from these strategies. Therefore, further studies investigating the molecular mechanisms that differentiate these trajectories are needed. Large-scale omics studies have identified key insights into the molecular mechanisms for many different diseases, however the application of these technologies to uncover the drivers of food allergy development is in its infancy. Here we review the use of omics approaches in food allergy and highlight key gaps in knowledge for applying these technologies for the characterization of food allergy development.

Allergic disease trajectories up to adolescence: Characteristics, early-life, and genetic determinants

BACKGROUND

Allergic diseases often develop jointly during early childhood but differ in timing of onset, remission, and progression. Their disease course over time is often difficult to predict and determinants are not well understood.

OBJECTIVES

We aimed to identify trajectories of allergic diseases up to adolescence and to investigate their association with early-life and genetic determinants and clinical characteristics.

METHODS

Longitudinal k-means clustering was used to derive trajectories of allergic diseases (asthma, atopic dermatitis, and rhinitis) in two German birth cohorts (GINIplus/LISA). Associations with early-life determinants, polygenic risk scores, food and aeroallergen sensitization, and lung function were estimated by multinomial models. The results were replicated in the independent Swedish BAMSE cohort.

RESULTS

Seven allergic disease trajectories were identified: "Intermittently allergic," "rhinitis," "early-resolving dermatitis," "mid-persisting dermatitis," "multimorbid," "persisting dermatitis plus rhinitis," and "early-transient asthma." Family history of allergies was more prevalent in all allergic disease trajectories compared the non-allergic controls with stronger effect sizes for clusters comprising more than one allergic disease (e.g., RRR = 5.0, 95% CI = [3.1-8.0] in the multimorbid versus 1.8 [1.4-2.4] in the mild intermittently allergic cluster). Specific polygenic risk scores for single allergic diseases were significantly associated with their relevant trajectories. The derived trajectories and their association with genetic effects and clinical characteristics showed similar results in BAMSE.

CONCLUSION

Seven robust allergic clusters were identified and showed associations with early life and genetic factors as well as clinical characteristics.

Systematic review and network meta-analysis of different types of emollient for the prevention of atopic dermatitis in infants

Prophylactic application of emollients has been an effective strategy against infant atopic dermatitis (AD); however, the difference of different emollients is unknown. We performed this network meta-analysis to compare different emollients in preventing infant AD. A systematic search was performed in PubMed, EMBASE and Cochrane library to identify relevant studies from their inception through 28 February, 2022. We evaluated the quality of eligible studies using the Cochrane risk of bias assessment tool. Data analysis was performed using STATA 14.0. Eleven studies were included for data analysis. Direct meta-analysis suggested that early application of emollients effectively prevented AD development in high-risk infants (risk ratio [RR], 0.64; 95% confidence interval [CI], 0.47 to 0.88). Network meta-analysis suggested that emollient emulsion might the better option for preventing infant AD development, with a surface under the cumulative ranking curve (SUCRA) of 82.6% for all populations, 78.0% for high-risk populations and 79.2% for populations with food sensitization. Moreover, subjects receiving emollients more frequently experienced adverse events. Overall, early application of emollients is an effective strategy for preventing AD development in high-risk infants and emollient emulsion may be the optimal type. Future study with well-designed and large scale are warranted to validate our findings.

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.

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Epicutaneous Sensitization and Food Allergy: Preventive Strategies Targeting Skin Barrier Repair-Facts and Challenges

Food allergy represents a growing public health and socio-economic problem with an increasing prevalence over the last two decades. Despite its substantial impact on the quality of life, current treatment options for food allergy are limited to strict allergen avoidance and emergency management, creating an urgent need for effective preventive strategies. Advances in the understanding of the food allergy pathogenesis allow to develop more precise approaches targeting specific pathophysiological pathways. Recently, the skin has become an important target for food allergy prevention strategies, as it has been hypothesized that allergen exposure through the impaired skin barrier might induce an immune response resulting in subsequent development of food allergy. This review aims to discuss current evidence supporting this complex interplay between the skin barrier dysfunction and food allergy by highlighting the crucial role of epicutaneous sensitization in the causality pathway leading to food allergen sensitization and progression to clinical food allergy. We also summarize recently studied prophylactic and therapeutic interventions targeting the skin barrier repair as an emerging food allergy prevention strategy and discuss current evidence controversies and future challenges. Further studies are needed before these promising strategies can be routinely implemented as prevention advice for the general population.

Early peanut introduction: To test or not to test?

OBJECTIVE

To review recent evidence and international guidelines on early peanut introduction for preventing peanut allergy and provide an update on the status of the debate around testing before early peanut introduction.

DATA SOURCES

Review of published literature documenting: infant feeding guidelines; impact of early peanut introduction on peanut allergy; risk factors for peanut allergy; and impact of early peanut introduction guidelines on infant feeding practices and allergy.

STUDY SELECTION

We used a narrative approach and present both pro and con arguments for testing before peanut introduction. Data from randomized controlled trials and post-hoc analyses of these trials and observational studies were included.

RESULTS

Allergy prevention guidelines around the world now consistently recommend introducing peanut into an infant's diet before 12 months of age for countries with high peanut allergy prevalence. In the US, guidelines recently shifted away from recommending allergy testing before introduction for those at risk of peanut allergy. There is evidence primarily from Australia that recommending early introduction without prior testing is safe and effective in increasing early peanut introduction for both high and low-risk infants, although the subsequent reduction in peanut allergy prevalence at the population level was less than expected.

CONCLUSION

Current evidence supports recommending early peanut introduction without routinely testing for peanut allergy. If testing is offered, this should be based on shared decision making between families and practitioners and only be undertaken where there is provision for rapid access to definitive diagnosis including oral food challenges.

Environmental Exposures may Hold the Key; Impact of Air Pollution, Greenness, and Rural/Farm Lifestyle on Allergic Outcomes

PURPOSE OF REVIEW

There has been an increased prevalence of allergy. Due to this relatively rapid rise, changes in environmental exposures are likely the main contributor. In this review, we highlight literature from the last 3 years pertaining to the role of air pollution, greenness, and the rural/farm lifestyle and their association with the development of allergic sensitization, atopic dermatitis, food allergy, and allergic rhinitis in infancy and childhood. Because asthma has a more complex pathophysiology, it was excluded from this review.

RECENT FINDINGS

Recent studies support a role for air pollution, greenness, and rural/farming lifestyle influencing atopic outcomes that continue to be defined. While many studies have examined singular environmental exposures, the interconnectedness of these exposures and others points to a need for future work to consider an individual's whole exposure. Environmental exposures' influence on atopic disease development remains an ongoing and important area of study.

Epidemiology of eczema in South-Eastern Australia

BACKGROUND/OBJECTIVES

Eczema is a common chronic debilitating skin condition in childhood. Data on the epidemiology and natural history of eczema across the life course are lacking. This analysis aimed to describe these epidemiological features in Australian children and adults.

METHODS

Data collected on eczema from four Australian cohort studies were analysed: namely HealthNuts, Melbourne Atopic Cohort Study (MACS), Tasmanian Longitudinal Health Study (TAHS) and the Australian arm of the European Community Respiratory Health Survey (ECRHS).

RESULTS

Among children aged under 6 years, 28.8%-35.6% have ever-had eczema, and 16.7%-26.6% had 'current eczema'. Among those aged 6-12 years, 14.6%-24.7% had 'current eczema' with 12.0%-18.5% of those at ages of 6 and 10 years classified as having moderate-to-severe eczema according to the Scoring of Atopic Dermatitis (SCORAD) index. In adults, the prevalence of 'eczema ever' ranged between 13.8% and 48.4%. The 12-month period prevalence of eczema was 15.1% at age 18, while current eczema was 8.5% at an average age of 51, and 8.8% at an average age 53 years. Eczema was more common among young boys, but this difference became non-significant for older children and early adolescents. In contrast, eczema was more common for adult women than men.

CONCLUSIONS

Eczema is common both in children and adults. The proportion of severe eczema in children was substantial.

Changes in Serum Protein-Peptide Patterns in Atopic Children Allergic to Plant Storage Proteins

Next to cow's milk and eggs, plant foods, i.e., legumes, tree nuts and cereal grains, most often sensitise atopic children. Storage proteins constitutes the most relevant protein fraction of plant foods, causing primary sensitisation. They exhibit strong allergenic properties and immunogenicity. Our goal was to analyse sensitisation to 26 plant storage proteins in a group of 76 children aged 0-5 years with chronic symptoms of atopic dermatitis using Allergy Explorer ALEX2 and to discover changes in serum protein-peptide patterns in allergic patients with the use of MALDI-TOF-MS. We reported that 25% of children were allergic to 2S albumins, 19.7% to 7S globulins, 13.2% to 11S globulins and 1.3% to cereal prolamins. The most common allergenic molecules were Ara h 1 (18.4%), Ara h 2 (17.1%), Ara h 6 (15.8%) and Ara h 3 (11.8%) from peanuts, and the mean serum sIgE concentrations in allergic patients were 10.93 kUA/L, 15.353 kUA/L, 15.359 kUA/L and 9.038 kUA/L, respectively. In children allergic to storage proteins compared to the other patients (both allergic and non-allergic), the cell cycle control protein 50A, testis-expressed sequence 13B, DENN domain-containing protein 5A and SKI family transcriptional corepressor 2 were altered. Our results indicate that the IgE-mediated allergy to storage proteins is a huge problem in a group of young, atopic children, and show the potential of proteomic analysis in the prediction of primary sensitisation to plant foods. It is the next crucial step for understanding the molecular consequences of allergy to storage proteins.

The prevalence of sensitization to food allergens in children with atopic dermatitis

INTRODUCTION

Atopic dermatitis (AD) has a complex pathophysiology. The course of the disease is affected by both environmental factors and allergen hypersensitivities. Food and aeroallergens have a significant role in the pathogenesis and disease control.

OBJECTIVE

In this study, it was aimed to determine the prevalence of food and aeroallergen sensitivity of children with AD.

METHODS

Children under 18 years with AD who applied to pediatric allergy and immunology outpatient clinics were evaluated. All patients had a skin prick test (SPT) within most common food and aeroallergens.

RESULTS

One hundred seventy three patients were studied. Most of the moderate and severe AD patients were boys (boys 64% vs. girls 47%). Symptoms started earlier and positive results in SPTs with food allergens were more common in patients with SCORAD (SCORing Atopic Dermatitis) >25 (p < 0.0001). Egg white (39%), egg yolk (31%), cow's milk (13%) and wheat flour (5%), were the most common allergens, respectively. The SCORAD scores were higher in multiple food sensitized patients' groups (p < 0.001). Although, food sensitizations were prevalent in patients who had higher SCORAD scores (p = 0.001), there was no significant difference in sensitization with aeroallergens. (p = 0.392).

CONCLUSION

Sensitizations to both food and aeroallergens are common in patients with AD. In addition, sensitization to these allergens and SCORAD severity in patients with AD have positive correlation.

Early-life exposure to air pollution associated with food allergy in children: Implications for 'one allergy' concept

BACKGROUND

The rapid increase of food allergy (FA) has become the "second wave" of allergy epidemic and is now a major global public health concern. Mounting evidence indicates that early life exposure to air pollution is associated with the "first wave" of allergy epidemic (including asthma, allergic rhinitis and eczema) in children, but little is known about its association with FA.

OBJECTIVES

We hypothesize FA has triple exposure pathways, gut-skin-airway, and investigate the effects of airway exposure to outdoor and indoor air pollution on childhood FA.

METHODS

A cohort study of 2598 preschool children aged 3-6 years old was conducted in Changsha, China. The prevalence of FA was surveyed using a standard questionnaire by International Study of Asthma and Allergies in Childhood (ISAAC). Exposure to indoor air pollution was assessed by four indicators: new furniture, redecoration, mold or dampness, and window condensation. Exposure to outdoor air pollution was evaluated by the concentrations of PM10, SO2 and NO2, which were obtained from the monitored stations. Both prenatal and postnatal exposure windows were considered. The association between exposure to outdoor/indoor air pollution and childhood FA was estimated by multiple logistic regression models using odds ratio (OR) and a 95% confidence interval (CI).

RESULTS

A total of 14.9% children reported FA. The prevalence was significantly associated with exposure to indoor air pollution, OR (95% CI) = 1.93 (1.35-2.75) for prenatal exposure to mold/dampness and 1.49 (1.07-2.10) and 1.41 (1.04-1.89) respectively for postnatal exposure to new furniture and window condensation. The prevalence of FA was also associated with prenatal and postnatal exposure to outdoor air pollution, particularly the traffic-related air pollutant NO2, with adjusted ORs (95% Cls) respectively 1.24 (1.00-1.54) and 1.38 (1.03-1.85) per interquartile range (IQR) increase. Sensitivity analysis showed that the association between outdoor/indoor air pollution and childhood FA was significant only in young children aged 3-4 years.

CONCLUSION

Early-life exposure to high levels of outdoor and indoor air pollution in China due to the rapid economic growth and fast urbanization in the past decades may contribute to the rapid increase of food allergy (FA) in children. Our study indicates that, in addition to gut and skin, airway may be a new route of food sensitization. Air pollution leads to the first and second waves of allergy epidemics, suggesting a concept of 'one allergy' disease.

Skin care interventions in infants for preventing eczema and food allergy

BACKGROUND

Eczema and food allergy are common health conditions that usually begin in early childhood and often occur in the same people. They can be associated with an impaired skin barrier in early infancy. It is unclear whether trying to prevent or reverse an impaired skin barrier soon after birth is effective for preventing eczema or food allergy.

OBJECTIVES

Primary objective To assess the effects of skin care interventions such as emollients for primary prevention of eczema and food allergy in infants. Secondary objective To identify features of study populations such as age, hereditary risk, and adherence to interventions that are associated with the greatest treatment benefit or harm for both eczema and food allergy.

SEARCH METHODS

We performed an updated search of the Cochrane Skin Specialised Register, CENTRAL, MEDLINE, and Embase in September 2021. We searched two trials registers in July 2021. We checked the reference lists of included studies and relevant systematic reviews, and scanned conference proceedings to identify further references to relevant randomised controlled trials (RCTs).  SELECTION CRITERIA: We included RCTs of skin care interventions that could potentially enhance skin barrier function, reduce dryness, or reduce subclinical inflammation in healthy term (> 37 weeks) infants (≤ 12 months) without pre-existing eczema, food allergy, or other skin condition. Eligible comparisons were standard care in the locality or no treatment. Types of skin care interventions could include moisturisers/emollients; bathing products; advice regarding reducing soap exposure and bathing frequency; and use of water softeners. No minimum follow-up was required.

DATA COLLECTION AND ANALYSIS

This is a prospective individual participant data (IPD) meta-analysis. We used standard Cochrane methodological procedures, and primary analyses used the IPD dataset. Primary outcomes were cumulative incidence of eczema and cumulative incidence of immunoglobulin (Ig)E-mediated food allergy by one to three years, both measured at the closest available time point to two years. Secondary outcomes included adverse events during the intervention period; eczema severity (clinician-assessed); parent report of eczema severity; time to onset of eczema; parent report of immediate food allergy; and allergic sensitisation to food or inhalant allergen.

MAIN RESULTS

We identified 33 RCTs comprising 25,827 participants. Of these, 17 studies randomising 5823 participants reported information on one or more outcomes specified in this review.  We included 11 studies, randomising 5217 participants, in one or more meta-analyses (range 2 to 9 studies per individual meta-analysis), with 10 of these studies providing IPD; the remaining 6 studies were included in the narrative results only.   Most studies were conducted at children's hospitals. Twenty-five studies, including all those contributing data to meta-analyses, randomised newborns up to age three weeks to receive a skin care intervention or standard infant skin care. Eight of the 11 studies contributing to meta-analyses recruited infants at high risk of developing eczema or food allergy, although the definition of high risk varied between studies. Durations of intervention and follow-up ranged from 24 hours to three years. All interventions were compared against no skin care intervention or local standard care. Of the 17 studies that reported information on our prespecified outcomes, 13 assessed emollients. We assessed most of the evidence in the review as low certainty and had some concerns about risk of bias. A rating of some concerns was most often due to lack of blinding of outcome assessors or significant missing data, which could have impacted outcome measurement but was judged unlikely to have done so. We assessed the evidence for the primary food allergy outcome as high risk of bias due to the inclusion of only one trial, where findings varied based on different assumptions about missing data. Skin care interventions during infancy probably do not change the risk of eczema by one to three years of age (risk ratio (RR) 1.03, 95% confidence interval (CI) 0.81 to 1.31; risk difference 5 more cases per 1000 infants, 95% CI 28 less to 47 more; moderate-certainty evidence; 3075 participants, 7 trials) or time to onset of eczema (hazard ratio 0.86, 95% CI 0.65 to 1.14; moderate-certainty evidence; 3349 participants, 9 trials). Skin care interventions during infancy may increase the risk of IgE-mediated food allergy by one to three years of age (RR 2.53, 95% CI 0.99 to 6.49; low-certainty evidence; 976 participants, 1 trial) but may not change risk of allergic sensitisation to a food allergen by age one to three years (RR 1.05, 95% CI 0.64 to 1.71; low-certainty evidence; 1794 participants, 3 trials). Skin care interventions during infancy may slightly increase risk of parent report of immediate reaction to a common food allergen at two years (RR 1.27, 95% CI 1.00 to 1.61; low-certainty evidence; 1171 participants, 1 trial); however, this was only seen for cow's milk, and may be unreliable due to over-reporting of milk allergy in infants. Skin care interventions during infancy probably increase risk of skin infection over the intervention period (RR 1.33, 95% CI 1.01 to 1.75; risk difference 17 more cases per 1000 infants, 95% CI one more to 38 more; moderate-certainty evidence; 2728 participants, 6 trials) and may increase the risk of infant slippage over the intervention period (RR 1.42, 95% CI 0.67 to 2.99; low-certainty evidence; 2538 participants, 4 trials) and stinging/allergic reactions to moisturisers (RR 2.24, 95% 0.67 to 7.43; low-certainty evidence; 343 participants, 4 trials), although CIs for slippages and stinging/allergic reactions were wide and include the possibility of no effect or reduced risk. Preplanned subgroup analyses showed that the effects of interventions were not influenced by age, duration of intervention, hereditary risk, filaggrin (FLG) mutation, chromosome 11 intergenic variant rs2212434, or classification of intervention type for risk of developing eczema. We could not evaluate these effects on risk of food allergy. Evidence was insufficient to show whether adherence to interventions influenced the relationship between skin care interventions and eczema or food allergy development.

AUTHORS' CONCLUSIONS

Based on low- to moderate-certainty evidence, skin care interventions such as emollients during the first year of life in healthy infants are probably not effective for preventing eczema; may increase risk of food allergy; and probably increase risk of skin infection. Further study is needed to understand whether different approaches to infant skin care might prevent eczema or food allergy.

Sialic acid and food allergies: The link between nutrition and immunology

Food allergies (FA), a major public health problem recognized by the World Health Organization, affect an estimated 3%-10% of adults and 8% of children worldwide. However, effective treatments for FA are still lacking. Recent advances in glycoimmunology have demonstrated the great potential of sialic acids (SAs) in the treatment of FA. SAs are a group of nine-carbon α-ketoacids usually linked to glycoproteins and glycolipids as terminal glycans. They play an essential role in modulating immune responses and may be an effective target for FA intervention. As exogenous food components, sialylated polysaccharides have anti-FA effects. In contrast, as endogenous components, SAs on immunoglobulin E and immune cell surfaces contribute to the pathogenesis of FA. Given the lack of comprehensive information on the effects of SAs on FA, we reviewed the roles of endogenous and exogenous SAs in the pathogenesis and treatment of FA. In addition, we considered the structure-function relationship of SAs to provide a theoretical basis for the development of SA-based FA treatments.

How a Family History of Allergic Diseases Influences Food Allergy in Children: The Japan Environment and Children's Study

The influence of family allergic history on food allergy in offspring in Japan is unknown. We analyzed data from a nationwide birth cohort study using logistic regression models to examine the associations of maternal, paternal, and both parental histories of allergic diseases (food allergy, atopic dermatitis, asthma, and rhinitis) with their child’s food allergy at 1.5 and 3 years of age. This analysis included 69,379 singleton full-term mothers and 37,179 fathers and their children. All parental histories of allergic diseases showed significant positive associations with their child’s food allergy. When both parents had a history of allergic diseases, the adjusted odds ratio (aOR) tended to be higher than when either parent had allergic diseases (p for trend < 0.0001). The highest aOR was detected when both parents had food allergy (2.60; 95% confidential interval, 1.58−4.27), and the aOR was 1.71 when either parent had food allergy (95% confidential interval, 1.54−1.91). The aORs were attenuated but still had significant positive associations after adjusting for the child’s atopic dermatitis, a risk factor for allergy development. In conclusion, all parental allergic diseases were significantly positively associated with their child’s food allergy. The effect of family history showed a stepwise increase in risk from either parent to both parents, and the highest risk of allergic disease was a parental history of food allergy.