Anaphylaxis has been defined as a ‘severe, life‐threatening generalized or systemic hypersensitivity reaction’. However, data indicate that the vast majority of food‐triggered anaphylactic reactions ...are not life‐threatening. Nonetheless, severe life‐threatening reactions do occur and are unpredictable. We discuss the concepts surrounding perceptions of severe, life‐threatening allergic reactions to food by different stakeholders, with particular reference to the inclusion of clinical severity as a factor in allergy and allergen risk management. We review the evidence regarding factors that might be used to identify those at most risk of severe allergic reactions to food, and the consequences of misinformation in this regard. For example, a significant proportion of food‐allergic children also have asthma, yet almost none will experience a fatal food‐allergic reaction; asthma is not, in itself, a strong predictor for fatal anaphylaxis. The relationship between dose of allergen exposure and symptom severity is unclear. While dose appears to be a risk factor in at least a subgroup of patients, studies report that individuals with prior anaphylaxis do not have a lower eliciting dose than those reporting previous mild reactions. It is therefore important to consider severity and sensitivity as separate factors, as a highly sensitive individual will not necessarily experience severe symptoms during an allergic reaction. We identify the knowledge gaps that need to be addressed to improve our ability to better identify those most at risk of severe food‐induced allergic reactions.
Food allergy can result in considerable morbidity, impact negatively on quality of life, and prove costly in terms of medical care. These guidelines have been prepared by the European Academy of ...Allergy and Clinical Immunology's (EAACI) Guidelines for Food Allergy and Anaphylaxis Group, building on previous EAACI position papers on adverse reaction to foods and three recent systematic reviews on the epidemiology, diagnosis, and management of food allergy, and provide evidence‐based recommendations for the diagnosis and management of food allergy. While the primary audience is allergists, this document is relevant for all other healthcare professionals, including primary care physicians, and pediatric and adult specialists, dieticians, pharmacists and paramedics. Our current understanding of the manifestations of food allergy, the role of diagnostic tests, and the effective management of patients of all ages with food allergy is presented. The acute management of non‐life‐threatening reactions is covered in these guidelines, but for guidance on the emergency management of anaphylaxis, readers are referred to the related EAACI Anaphylaxis Guidelines.
Serological tests for immunoglobulin G4 (IgG4) against foods are persistently promoted for the diagnosis of food-induced hypersensitivity. Since many patients believe that their symptoms are related ...to food ingestion without diagnostic confirmation of a causal relationship, tests for food-specific IgG4 represent a growing market. Testing for blood IgG4 against different foods is performed with large-scale screening for hundreds of food items by enzyme-linked immunosorbent assay-type and radioallergosorbent-type assays in young children, adolescents and adults. However, many serum samples show positive IgG4 results without corresponding clinical symptoms. These findings, combined with the lack of convincing evidence for histamine-releasing properties of IgG4 in humans, and lack of any controlled studies on the diagnostic value of IgG4 testing in food allergy, do not provide any basis for the hypothesis that food-specific IgG4 should be attributed with an effector role in food hypersensitivity. In contrast to the disputed beliefs, IgG4 against foods indicates that the organism has been repeatedly exposed to food components, recognized as foreign proteins by the immune system. Its presence should not be considered as a factor which induces hypersensitivity, but rather as an indicator for immunological tolerance, linked to the activity of regulatory T cells. In conclusion, food-specific IgG4 does not indicate (imminent) food allergy or intolerance, but rather a physiological response of the immune system after exposition to food components. Therefore, testing of IgG4 to foods is considered as irrelevant for the laboratory work-up of food allergy or intolerance and should not be performed in case of food-related complaints.
In older children, adolescents, and adults, a substantial part of all IgE‐mediated food allergies is caused by cross‐reacting allergenic structures shared by inhalants and foods. IgE stimulated by a ...cross‐reactive inhalant allergen can result in diverse patterns of allergic reactions to various foods. Local, mild, or severe systemic reactions may occur already after the first consumption of a food containing a cross‐reactive allergen. In clinical practice, clinically relevant sensitizations are elucidated by skin prick testing or by the determination of specific IgE in vitro. Component‐resolved diagnosis may help to reach a diagnosis and may predict the risk of a systemic reaction. Allergy needs to be confirmed in cases of unclear history by oral challenge tests. The therapeutic potential of allergen immunotherapy with inhalant allergens in pollen‐related food allergy is not clear, and more placebo‐controlled studies are needed. As we are facing an increasing incidence of pollen allergies, a shift in sensitization patterns and changes in nutritional habits, and the occurrence of new, so far unknown allergies due to cross‐reactions are expected.
Background
Complaints of ‘food allergy’ are increasing. Standardized surveys of IgE sensitization to foods are still uncommon and multicountry surveys are rare. We have assessed IgE sensitization to ...food‐associated allergens in different regions of Europe using a common protocol.
Methods
Participants from general populations aged 20–54 years in eight European centres (Zurich, Madrid, Utrecht, Lodz, Sophia, Athens, Reykjavik and Vilnius) were asked whether they had allergic symptoms associated with specific foods. Weighted samples of those with and without allergic symptoms then completed a longer questionnaire and donated serum for IgE analysis by ImmunoCAP for 24 foods, 6 aeroallergens and, by allergen microarray, for 48 individual food proteins.
Results
The prevalence of IgE sensitization to foods ranged from 23.6% to 6.6%. The least common IgE sensitizations were to fish (0.2%), milk (0.8%) and egg (0.9%), and the most common were to hazelnut (9.3%), peach (7.9%) and apple (6.5%). The order of prevalence of IgE sensitization against different foods was similar in each centre and correlated with the prevalence of the pollen‐associated allergens Bet v 1 and Bet v 2 (r = 0.86). IgE sensitization to plant allergen components unrelated to pollen allergens was more evenly distributed and independent of pollen IgE sensitization (r = −0.10). The most common foods containing allergens not cross‐reacting with pollens were sesame, shrimp and hazelnut.
Discussion
IgE sensitization to foods is common, but varies widely and is predominantly related to IgE sensitization to pollen allergens. IgE sensitization to food allergens not cross‐reacting with pollens is rare and more evenly distributed.
Summary
Background
Hand eczema has a high incidence and prevalence and has a negative impact on both physical and psychological well‐being, with the risk of persistence as a chronic condition. ...Epidemiological studies on hand eczema provided mainly descriptive and risk analyses, but pattern analyses of variables associated with hand eczema, in particular chronic hand eczema, have not been explored to date.
Objectives
To investigate and display the semantics of associations between variables of hand eczema obtained from the Swiss and German registries of chronic hand eczema (CARPE) to dissect patterns and novel links.
Methods
This was a cross‐sectional study on selected variables from the CARPE registries. Associations between variables were analysed by means of an autoassociative system. A semantic connectivity map was generated by using a maximum spanning tree algorithm.
Results
Baseline datasets of 1466 patients with chronic hand eczema (Switzerland: 199; Germany: 1267) were analysed. Occupational exposure had the highest impact in the total and country cohorts. We identified two areas of exposure linked to corresponding occupations that clearly demarcated the sexes.
Conclusions
This study, using semantic connectivity as a novel method of data analysis, reveals the complexity of features characterizing chronic hand eczema as well as novel association patterns that deserve further investigation.
What's already known about this topic?
Chronic hand eczema is a multifactorial disease.
Epidemiological studies on hand eczema provide mainly descriptive and risk analyses.
What does this study add?
A novel statistical method called semantic map analysis is applied.
Semantic connectivity maps show the association patterns of data obtained from chronic hand eczema registries in Germany and Switzerland.
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Premarket, genetically modified (GM) plants are assessed for potential risks of food allergy. The major risk would be transfer of a gene encoding an allergen or protein nearly identical to an ...allergen into a different food source, which can be assessed by specific serum testing. The potential that a newly expressed protein might become an allergen is evaluated based on resistance to digestion in pepsin and abundance in food fractions. If the modified plant is a common allergenic source (e.g. soybean), regulatory guidelines suggest testing for increases in the expression of endogenous allergens. Some regulators request evaluating endogenous allergens for rarely allergenic plants (e.g. maize and rice). Since allergic individuals must avoid foods containing their allergen (e.g. peanut, soybean, maize, or rice), the relevance of the tests is unclear. Furthermore, no acceptance criteria are established and little is known about the natural variation in allergen concentrations in these crops. Our results demonstrate a 15‐fold difference in the major maize allergen, lipid transfer protein between nine varieties, and complex variation in IgE binding to various soybean varieties. We question the value of evaluating endogenous allergens in GM plants unless the intent of the modification was production of a hypoallergenic crop.
Background
We tested the hypothesis that specific molecular sensitization patterns correlate with the clinical data/manifestation in a European peanut‐allergic population characterized under a common ...protocol.
Methods
Sixty‐eight peanut‐allergic subjects and 82 tolerant controls from 11 European countries were included. Allergy to peanut and lowest symptom‐eliciting dose was established by double‐blind placebo‐controlled food challenge in all but anaphylactic subjects. Information of early or late (before or after 14 years of age) onset of peanut allergy was obtained from standardized questionnaires. IgE to peanut allergens rAra h 1–3, 6, 8–9, profilin and CCD was determined using ImmunoCAP.
Results
Seventy‐eight percent of peanut allergics were sensitized to peanut extract and 90% to at least one peanut component. rAra h 2 was the sole major allergen for the peanut‐allergic population. Geographical differences were observed for rAra h 8 and rAra h 9, which were major allergens for central/western and southern Europeans, respectively. Sensitization to rAra h 1 and 2 was exclusively observed in early‐onset peanut allergy. Peanut‐tolerant subjects were frequently sensitized to rAra h 8 or 9 but not to storage proteins. Sensitization to Ara h 2 ≥ 1.0 kUA/l conferred a 97% probability for a systemic reaction (P = 0.0002). Logistic regression revealed a significant influence of peanut extract sensitization and region on the occurrence of systemic reactions (P = 0.0185 and P = 0.0436, respectively).
Conclusion
Sensitization to Ara h 1, 2 and 3 is usually acquired in childhood. IgE to Ara h 2 ≥ 1.0 kUA/l is significantly associated with the development of systemic reactions to peanut.
Thresholds constitute a critical piece of information in assessing the risk from allergenic foods at both the individual and population levels. Knowledge of the minimum dose that can elicit a ...reaction is of great interest to all food allergy stakeholders. For allergic individuals and health professionals, individual threshold data can inform allergy management. Population thresholds can help both the food industry and regulatory authorities assess the public health risk and design appropriate food safety objectives to guide risk management. Considerable experience has been gained with the double-blind placebo-controlled food challenge (DBPCFC), but only recently has the technique been adapted to provide data on thresholds. Available data thus vary greatly in quality, with relatively few studies providing the best quality individual data, using the low-dose DBPCFC. Such high quality individual data also form the foundation for population thresholds, but these also require, in addition to an adequate sample size, a good characterization of the tested population in relation to the whole allergic population. Determination of thresholds at both an individual level and at a population level is influenced by many factors. This review describes a low-dose challenge protocol developed as part of the European Community-funded Integrated Project Europrevall, and strongly recommends its wider use so that data are generated that can readily increase the power of existing studies.
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