Diagnosis and Management of Pollen Food Allergy Syndrome to Nuts.

Oral allergy syndrome or pollen food allergy syndrome (PFAS) represents a common clinical conundrum when the reported trigger food is a tree nut (usually almond or hazelnut) or peanut. The PFAS may give rise to uncertainty about the potential severity of the future reactions, indications for prescribing epinephrine, and the extent of the necessary dietary avoidance. As a food allergy, secondary to cross-reactivity with airborne pollen, PFAS usually manifests toward the end of the first decade of life as contact urticaria of the oropharyngeal mucous membranes. Molecular allergology facilitates diagnosis and risk stratification by establishing the profile of sensitization. Exclusive sensitization to pathogenesis-related proteins family 10 (PR10) and profilins indicates that signs and symptoms are due to PFAS, whereas sensitization to seed storage proteins with or without sensitization to PR10 and profilins may indicate a more severe primary nut allergy phenotype. Management relies on avoidance of the specific nut trigger, advice on the likelihood of more severe local or systemic symptoms, and treatment of reactions according to the severity. Future studies are needed to better delineate the risk of systemic reactions in individuals with nut PFAS and to establish the role of food or pollen allergen immunotherapy for the prevention or moderation of this condition.

BSACI guideline for the diagnosis and management of pollen food syndrome in the UK.

Pollen food syndrome (PFS) is a highly prevalent food allergy affecting pollen-sensitized children and adults. Sufferers experience allergic symptoms when consuming raw plant foods, due to the homology between the pollen allergens and unstable proteins in these foods. The triggers involved can vary depending on the pollen sensitization, which in turn is affected by geographical location. The British Society of Allergy and Clinical Immunology (BSACI) Standards of Care Committee (SOCC) identified a need to develop a guideline for the diagnosis and management of PFS in the United Kingdom (UK). Guidelines produced by the BSACI use either the GRADE or SIGN methodology; due to a lack of high-quality evidence these recommendations were formulated using the SIGN guidelines, which is acknowledged to be less robust than the GRADE approach. The correct diagnosis of PFS ensures the avoidance of a misdiagnosis of a primary peanut or tree nut allergy or confusion with another plant food allergy to non-specific lipid transfer proteins. The characteristic foods involved, and rapid-onset oropharyngeal symptoms, mean PFS can often be diagnosed from the clinical history alone. However, reactions involving tree nuts, peanuts and soya milk or severe/atypical reactions to fruits and vegetables may require additional diagnostic tests. Management is through the exclusion of known trigger foods, which may appear to be simple, but is highly problematic if coupled with a pre-existing food allergy or for individuals following a vegetarian/vegan diet. Immunotherapy to pollens is not an effective treatment for PFS, and although oral or sublingual immunotherapy to foods seems more promising, large, controlled studies are needed. The typically mild symptoms of PFS can lead to an erroneous perception that this condition is always easily managed, but severe reactions can occur, and anxiety about the onset of symptoms to new foods can have a profound effect on quality of life.

EAACI guideline: Preventing the development of food allergy in infants and young children (2020 update).

BACKGROUND: This guideline from the European Academy of Allergy and Clinical Immunology (EAACI) recommends approaches to prevent the development of immediate-onset / IgE-mediated food allergy in infants and young children. It is an update of a 2014 EAACI guideline. METHODS: The guideline was developed using the AGREE II framework and the GRADE approach. An international Task Force with representatives from 11 countries and different disciplinary and clinical backgrounds systematically reviewed research and considered expert opinion. Recommendations were created by weighing up benefits and harms, considering the certainty of evidence and examining values, preferences and resource implications. The guideline was peer-reviewed by external experts, and feedback was incorporated from public consultation. RESULTS: All of the recommendations about preventing food allergy relate to infants (up to 1 year) and young children (up to 5 years), regardless of risk of allergy. There was insufficient evidence about preventing food allergy in other age groups. The EAACI Task Force suggests avoiding the use of regular cow's milk formula as supplementary feed for breastfed infants in the first week of life. The EAACI Task Force suggests introducing well-cooked, but not raw egg or uncooked pasteurized, egg into the infant diet as part of complementary feeding. In populations where there is a high prevalence of peanut allergy, the EAACI Task Force suggests introducing peanuts in an age-appropriate form as part of complementary feeding. According to the studies, it appears that the most effective age to introduce egg and peanut is from four to 6 months of life. The EAACI Task Force suggests against the following for preventing food allergy: (i) avoiding dietary food allergens during pregnancy or breastfeeding; and (ii) using soy protein formula in the first 6 months of life as a means of preventing food allergy. There is no recommendation for or against the following: use of vitamin supplements, fish oil, prebiotics, probiotics or synbiotics in pregnancy, when breastfeeding or in infancy; altering the duration of exclusive breastfeeding; and hydrolysed infant formulas, regular cow's milk-based infant formula after a week of age or use of emollients. CONCLUSIONS: Key changes from the 2014 guideline include suggesting (i) the introduction of peanut and well-cooked egg as part of complementary feeding (moderate certainty of evidence) and (ii) avoiding supplementation with regular cow's milk formula in the first week of life (low certainty of evidence). There remains uncertainty in how to prevent food allergy, and further well-powered, multinational research using robust diagnostic criteria is needed.

Dietary factors during pregnancy and atopic outcomes in childhood: A systematic review from the European Academy of Allergy and Clinical Immunology.

RATIONALE: Allergic diseases are an increasing public health concern, and early life environment is critical to immune development. Maternal diet during pregnancy has been linked to offspring allergy risk. In turn, maternal diet is a potentially modifiable factor, which could be targeted as an allergy prevention strategy. In this systematic review, we focused on non-allergen-specific modifying factors of the maternal diet in pregnancy on allergy outcomes in their offspring. METHODS: We undertook a systematic review of studies investigating the association between maternal diet during pregnancy and allergic outcomes (asthma/wheeze, hay fever/allergic rhinitis/seasonal allergies, eczema/atopic dermatitis (AD), food allergies, and allergic sensitization) in offspring. Studies evaluating the effect of food allergen intake were excluded. We searched three bibliographic databases (MEDLINE, EMBASE, and Web of Science) through February 26, 2019. Evidence was critically appraised using modified versions of the Cochrane Collaboration Risk of Bias tool for intervention trials and the National Institute for Clinical Excellence methodological checklist for cohort and case-control studies and meta-analysis performed from RCTs. RESULTS: We identified 95 papers: 17 RCTs and 78 observational (case-control, cross-sectional, and cohort) studies. Observational studies varied in design and dietary intakes and often had contradictory findings. Based on our meta-analysis, RCTs showed that vitamin D supplementation (OR: 0.72; 95% CI: 0.56-0.92) is associated with a reduced risk of wheeze/asthma. A positive trend for omega-3 fatty acids was observed for asthma/wheeze, but this did not reach statistical significance (OR: 0.70; 95% CI: 0.45-1.08). Omega-3 supplementation was also associated with a non-significant decreased risk of allergic rhinitis (OR: 0.76; 95% CI: 0.56-1.04). Neither vitamin D nor omega-3 fatty acids were associated with an altered risk of AD or food allergy. CONCLUSIONS: Prenatal supplementation with vitamin D may have beneficial effects for prevention of asthma. Additional nutritional factors seem to be required for modulating the risk of skin and gastrointestinal outcomes. We found no consistent evidence regarding other dietary factors, perhaps due to differences in study design and host features that were not considered. While confirmatory studies are required, there is also a need for performing RCTs beyond single nutrients/foods.

Preventing food allergy in infancy and childhood: Systematic review of randomised controlled trials.

BACKGROUND: This systematic review of ways to prevent immediate-onset/IgE-mediated food allergy will inform guidelines by the European Academy of Allergy and Immunology (EAACI). METHODS: The GRADE approach was used. Eleven databases were searched from 1946 to October 2019 for randomized controlled trials (and large prospective cohort studies in the case of breastfeeding). The studies included heterogeneous interventions, populations, and outcomes and so were summarized narratively. RESULTS: Forty-six studies examined interventions to reduce the risk of food allergy in infancy (up to 1 year) or early childhood. The following interventions for pregnant or breastfeeding women and/or infants may have little to no effect on preventing food allergy, but the evidence is very uncertain: dietary avoidance of food allergens, vitamin supplements, fish oil, probiotics, prebiotics, synbiotics, and emollients. Breastfeeding, hydrolyzed formulas, and avoiding cow's milk formula may not reduce the risk of cow's milk protein allergy; however, temporary supplementation with cow's milk formula in the first week of life may increase the risk of cow's milk allergy. Introducing well-cooked egg, but not pasteurized raw egg, from 4 to 6 months probably reduces the risk of hen's egg allergy. Introducing regular peanut consumption into the diet of an infant at increased risk beginning from 4 to 11 months probably results in a large reduction in peanut allergy in countries with a high prevalence. These conclusions about introducing peanut are based on moderate certainty evidence, from single trials in high-income countries. CONCLUSIONS: Sixty percent of the included studies were published in the last 10 years, but much still remains to be understood about preventing food allergy. In particular, there is a need to validate the potential benefits of early introduction of food allergens in a wider range of populations.

EAACI position paper: Influence of dietary fatty acids on asthma, food allergy, and atopic dermatitis.

The prevalence of allergic diseases such as allergic rhinitis, asthma, food allergy, and atopic dermatitis has increased dramatically during the last decades, which is associated with altered environmental exposures and lifestyle practices. The purpose of this review was to highlight the potential role for dietary fatty acids, in the prevention and management of these disorders. In addition to their nutritive value, fatty acids have important immunoregulatory effects. Fatty acid-associated biological mechanisms, human epidemiology, and intervention studies are summarized in this review. The influence of genetics and the microbiome on fatty acid metabolism is also discussed. Despite critical gaps in our current knowledge, it is increasingly apparent that dietary intake of fatty acids may influence the development of inflammatory and tolerogenic immune responses. However, the lack of standardized formats (ie, food versus supplement) and standardized doses, and frequently a lack of prestudy serum fatty acid level assessments in clinical studies significantly limit our ability to compare allergy outcomes across studies and to provide clear recommendations at this time. Future studies must address these limitations and individualized medical approaches should consider the inclusion of specific dietary factors for the prevention and management of asthma, food allergy, and atopic dermatitis.

Prevention of food allergy.

Despite a trend towards delayed weaning, food allergies (FAs) have increased in the past few decades and are now considered a public health concern, resulting in significant morbidity as well as occasional mortality. Whilst genetic factors are clearly important in the development of FA, a rise in FAs has occurred over a short period of time and is therefore unlikely to be due to germ-line genetic changes alone. Thus, it seems plausible that one or more environmental exposures may, via epigenetic changes, result in the interruption of the 'default immunologic state' of tolerance to foods. Strategies are therefore required for the prevention of FA: primary prevention seeks to prevent the onset of IgE-sensitisation; secondary prevention seeks to interrupt the development of FA in IgE-sensitised children; and tertiary prevention seeks to reduce the expression of 'end-organ' allergic disease in children with established FA. This chapter will outline the major findings in this field, with the aim of equipping the clinician with an evidence-based approach to a burgeoning yet poorly understood clinical problem. We also highlight the methodological challenges hindering the interpretation of existing FA studies. Fortunately, there are now robust studies underway, the results of which are expected to guide public health recommendations with respect to how and when to introduce major allergenic foods to children, regardless of allergic risk.

The RCPCH care pathway for children with latex allergies: an evidence- and consensus-based national approach.

AIMS: The Royal College of Paediatrics and Child Health (RCPCH) Science and Research Department was commissioned by the Department of Health to develop national care pathways for children with allergies; the latex allergy pathway is the seventh pathway. The pathways focus on defining the competences to improve the equity of care received by children with allergic conditions. METHOD: The RCPCH latex allergy pathway was developed by a multidisciplinary working group and was based on a comprehensive review of evidence. The pathway was reviewed by a broad group of stakeholders including the public and approved by the Allergy Care Pathways Project Board and the RCPCH Clinical Standards Committee. RESULTS: The results are presented in four parts, the evidence review, pathway mapping, external review and core knowledge documents. The evidence review highlighted the paucity of recent evidence for latex allergy in childhood. The review found that the diagnostic sensitivity of different latex extracts for skin-prick testing may differ. It also noted that health professionals should be aware of latex allergy, and care should be taken to avoid contact with latex in young infants, especially when there is a family history for latex allergy. The pathway entry points are defined by the severity at presentation. CONCLUSIONS: The latex allergy pathway provides a guide for training and development of services to facilitate improvements in delivery as close to the patients home as possible. The authors recommend that this pathway is implemented locally by a multidisciplinary team with a focus on creating networks between primary, secondary and tertiary care to improve services for children with allergic conditions.

The RCPCH care pathway for children with venom allergies: an evidence and consensus based national approach.

AIMS: The Royal College of Paediatrics and Child Health (RCPCH) Science & Research Department was commissioned by the Department of Health to develop national care pathways for children with allergies; the venom allergy pathway is the seventh pathway. The pathways focus on defining the competences to improve the equity of care received by children with allergic conditions. METHOD: The RCPCH venom allergy pathway was developed by a multidisciplinary working group and was based on a comprehensive review of evidence. The pathway was reviewed by a broad group of stakeholders including the public and approved by the Allergy Care Pathways Project Board and the RCPCH Clinical Standards Committee. RESULTS: The pathway results are presented in four parts: evidence review, mapping, external review and core knowledge documents. The entry points are defined and the ideal pathway of care is described from self-care through to follow-up. The evidence highlighted that venom immunotherapy is safe and effective for bee and wasp allergy and that there are real quality of life benefits for patients. The review also highlighted the value of measuring serum tryptase after reactions. CONCLUSIONS: The venom allergy pathway provides a guide for training and development of services to facilitate improvements in delivery as close to the patient's home as possible. The authors recommend that this pathway should be implemented locally by a multidisciplinary team with a focus on creating networks between primary, secondary and tertiary care to improve services for children with allergic conditions.

Can food allergy be prevented? The current evidence.

Food allergy is a recognized public health concern, for which preventative strategies are required. Although an intervention that adequately protects against the development of food allergy has still to be identified, limited benefits have been shown for the prevention of related allergic conditions such as eczema, and to a lesser extent asthma and rhinitis; these benefits are usually limited to at-risk populations. Prevention strategies need to be tested using randomized controlled study designs that account for the numerous methodological challenges, safety concerns, and necessary ethical limitations.