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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.

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.

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.

Carrot is a frequent cause of food allergy in Europe. The objective of this study was to evaluate a panel of carrot allergens for diagnosis of carrot allergy in Spain, Switzerland and Denmark.

PRISM revealed a high burden of suffering in chronic urticaria and provided helpful additional information for the management of these patients. In our cohort, cognitive flexibility was a positive predictive marker for the course of chronic urticaria.

Annährend 30% der Bevölkerung glauben, an einer Nahrungsmittelallergie zu leiden. Deren Prävalenz ist mit 4-8% zwar relativ hoch, jedoch deutlich niedriger als befürchtet. Ist die Diagnose gesichert, müssen die Betroffenen, besonders wenn Sie zusätzlich unter Asthma leiden, über Deklarationshinweise für die betreffenden Lebensmittelallergene sowie Gefahrenmahlzeiten ausreichend Bescheid wissen. Da absolute Allergenkarenz aber nicht immer möglich ist, sollten Nahrungsmittelallergiker stets ein Notfallset bei sich führen.

In many cases, patients allergic to birch pollen also show allergic reactions after ingestion of certain fruits or vegetables. This observation is explained on the molecular level by cross-reactivity of IgE antibodies induced by sensitization to the major birch pollen allergen Bet v 1 with homologous food allergens. As IgE antibodies recognize conformational epitopes, a precise structural characterization of the allergens involved is necessary to understand cross-reactivity and thus to develop new methods of allergen-specific immunotherapy for allergic patients. Here we report the three-dimensional solution structure of the soybean allergen Gly m 4, a member of the superfamily of Bet v 1 homologous proteins and a cross-reactant with IgE antibodies originally raised against Bet v 1 as shown by immunoblot inhibition and histamine release assays. Although the overall fold of Gly m 4 is very similar to that of Bet v 1, the three-dimensional structure of these proteins differ in detail. The Gly m 4 local structures that display those differences are also found in proteins from yellow lupine with known physiological function. The three-dimensional structure of Gly m 4 may thus shed some light on the physiological function of this subgroup of PR10 proteins as we as, in combination with immunological data, allow to propose surface patches that might represent cross-reactive epitopes.

This article aims to critically review developments in food allergy diagnostics with regard to the verification of specific IgE antibodies and the identification of the responsible allergens. Results of IgE-binding tests with food extracts are hampered by cross-reactive proteins, low-quality test agents, or both. Specificity can be increased by defining adequate cutoff values, whereas sensitivity can be improved by using high-quality test agents. IgE-binding tests with purified allergens enabled reliable quantification of allergen-specific IgE titers, with higher levels found in individuals with food allergy compared with individuals without food allergy. However, the overlap in individual test reactivity between allergic and nonallergic subjects complicates interpretation. Recombinant allergens and synthetic sequential epitopes enabled detection of sensitization profiles, with IgE specific to several allergens and substructures now being suggested as markers of severity, persistence, or both. However, high-power quantitative studies with larger numbers of patients are required to confirm these markers. IgE-binding tests merely indicate sensitization, whereas the final proof of clinical relevance still relies on family/case history, physical examinations, and provocation tests. Novel technologies promise superior diagnostics. Microarray technology permits simultaneous measurement of multiple IgE reactivities regarding specificity, abundance, reactivity, or interaction. Improved functional tests might enable reliable estimation of the clinical relevance of IgE sensitizations at justifiable expenses.

Die pollenassoziierte Nahrungsmittelallergie beruht auf einer Struktur- und Sequenzähnlichkeit allergener Proteine in Pollen und pflanzlichen Nahrungsmitteln. Die primäre IgE-Antwort richtet sich bei betroffenen Patienten in der Regel primär gegen Epitope auf Pollenproteinen mit sekundärer Erkennung homologer Epitope auf Nahrungsmittelallergenen. So leiden z.B. in Zentral- und Nordeuropa bis zu 80% der Birkenpollenallergiker gleichzeitig unter einer Nahrungsmittelallergie insbesondere gegen Stein- und Kernobst sowie gegen verschiedene Nüsse und Gemüse. Die Hauptmanifestation der pollenassoziierten Nahrungsmittelallergie ist das orale Allergiesyndrom, eine Kontakturtikaria der Mundschleimhaut. Neben der Kontakturtikaria insbesondere der Hände bei Berührung der allergenen Nahrungsmittel entwickeln Patienten mit pollenassoziierter Nahrungsmittelallergie bei deren Einnahme v.a. generalisierte Urtikaria und Angioödeme als kutane Symptome. Der Einfluss einer pollenassoziierten Nahrungsmittelallergie auf die Ausprägung und den Verlauf des atopischen Ekzems ist bis heute noch nicht definitiv geklärt