Food allergy

Food allergies' following food incompatibilities, which are not caused immunologically. Mostly allergic symptoms are caused by cow's milk or chicken eggs. Allergic reactions are preceded by sensitizing events; certain characteristics of foodstuffs and conditions in the human body facilitate their development. Gastrointestinal symptoms very often are just accompanying signs. In differential diagnosis the so-called "pseudo-allergies' following food ingestion have to be separated. Most important diagnostic measures are clinical history, prick-/scratch test, RAST, gastrointestinal provocation and abstinence test. The therapeutic program consists of allergen abstinence, avoiding all allergy-arousing factors, oral desensitizing and pharmaceutical treatment.     

Food allergy: an overview

Food allergy affects between 5% and 7.5% of children and between 1% and 2% of adults. The greater prevalence of food allergy in children reflects both the increased predisposition of children to develop food allergies and the development of immunologic tolerance to certain foods over time. Immunoglobulin (Ig) E-mediated food allergies can be classified as those that persist indefinitely and those that are predominantly transient. Although there is overlap between the two groups, certain foods are more likely than others to be tolerated in late childhood and adulthood. The diagnosis of food allergy rests with the detection of food-specific IgE in the context of a convincing history of type I hypersensitivity-mediated symptoms after ingestion of the suspected food or by eliciting IgE-mediated symptoms after controlled administration of the suspected food. Presently, the only available treatment of food allergies is dietary vigilance and administration of self-injectable epinephrine.     

Food allergy in the XXI century

Food allergy is a clinical state of high frequency and possible risk to life. This article reviews the foodstuffs most often responsible for serious reactions, including data from the Autonomous Community of Navarre. Given that dietetic elimination is the primordial long term treatment for food allergy, its difficulties, limitations and risks are analyzed. Finally, we set out the new perspectives offered by technology in the field of food allergy, both in the production of hypoallergens and in the development of new forms of immunotherapy.     

Food allergy: nuts and tree nuts

Nuts are a well-defined cause of food allergy, which affect approximately 1 % of the general population in the UK and the USA. There do appear to be differences in the frequency of nut allergy between different countries because of different dietary habits and cooking procedures. For example, in the USA and France, peanuts are one of the most frequent causes of food allergy, but in other countries, it seems to be less common. Genetic factors, in particular, appear to play a role in the development of peanut allergy. While the majority of nut allergens are seed storage proteins, other nut allergens are profilins and pathogenesis-related protein homologues, considered as panallergens because of their widespread distribution in plants. The presence of specific IgE antibodies to several nuts is a common clinical finding, but the clinical relevance of this cross-reactivity is usually limited. Allergic reactions to nuts appear to be particularly severe, sometimes even life-threatening, and fatal reactions following their ingestion have been documented. Food allergy is diagnosed by identifying an underlying immunological mechanism (i.e. allergic testing), and establishing a causal relationship between food ingestion and symptoms (i.e. oral challenges). In natural history investigations carried out in peanut-allergic children, approximately 20 % of the cases outgrew their allergy or developed oral tolerance. The treatment of nut allergies should include patient and family education about avoiding all presentations of the food and the potential for a severe reaction caused by accidental ingestion. Patients and families should be instructed how to recognise early symptoms of an allergic reaction and how to treat severe anaphylaxis promptly.     

Food allergy challenges: guidelines and implications

Double-blind placebo-controlled food challenges were used to determine the presence or absence of food hypersensitivity in 120 children with atopic dermatitis. Foods to be challenged were selected on the basis of history, allergy skin tests, nutritional significance, and patient desires. Dehydrated foods were hidden in capsules or juice and administered twice a day. Antigens were obtained commercially or prepared through a process of freeze-drying and subsequent pulverization. Cutaneous, gastrointestinal, nasal, and/or respiratory symptoms occurred following 133 challenges. Although patients exhibited multiple positive skin tests to foods, 86% experienced a positive response on blinded challenge to only one or two foods. Double-blind placebo-controlled food challenges accurately diagnose food hypersensitivity and minimize the number of foods eliminated from allergy avoidance diets. A new method of elimination diet management and education is based on the identification of "key words" on food labels. Instructional diet sheets were developed to teach this concept, which was found to promote greater confidence, compliance, and creativity in diet planning.     

Food intolerance and allergy in gastrointestinal disorders.

Approximately 60 tonnes of food passes through the gastrointestinal tract in an average lifetime. With a surface area second only to the respiratory tract, it is surprising that adverse reactions to food do not occur more frequently.     

Food allergy: gambling your life on a take-away meal

This study investigates whether or not it is possible to buy meals suitable for peanut allergy sufferers and assesses the training and guidance needs of catering staff and Environmental Health Officers (EHOs) in Northern Ireland with respect to serious food allergies. Meal samples purchased in food premises in the local authority regions of Northern Ireland (NI) were subjected to chemical analysis to check the assertions of the premises staff that they were suitable for peanut allergy sufferers. Officers also assessed if the customer was provided with any information on the allergenic status of foods produced by the establishment; if the EHOs taking the samples had received any training or guidance in allergy-related issues and to gauge the need for such training and guidance. Approximately one in five (13/62) of the premises provided meals which could possibly have triggered a fatal reaction in the purchaser. Most front of house staff did not check the allergen status of the meal with those doing the cooking and most EHOs felt that they needed more training in the subject of food allergen control in commercial food premises. It is important for food allergy sufferers and their medical advisers to be made aware of the limitations of avoidance advice and that false assurances persist of the absence of peanut protein in takeaway foods.     

Food allergy and social anxiety in a community sample of adolescents

This investigation explored the relationship between food allergies and social anxiety in a school-based sample of adolescents. A total of 849 participants, including 87 endorsing food allergies, completed standardized questionnaires assessing social anxiety symptoms. Food allergic participants answered questions assessing allergy characteristics, worry and avoidance related to allergen exposure and allergy disclosure, and parental worry and control. Boys with food allergies reported higher social anxiety than boys without food allergies, though no differences were found in girls. Social anxiety was correlated with parental worry and control. Findings may inform anxiety prevention programs for youth with food allergies.     

Food allergy and intolerance in children and adolescents, an update

Epidemiological surveys demonstrate that rapid increase in allergic diseases is a real phenomenon. In developed countries they are about the commonest chronic diseases, reaching between 15% and 30% of the population. Adverse reaction to food can be divided into toxic reaction and non-toxic reactions. The non-toxic reactions are divided into non-immune mediated and immune mediated, these are considered food allergic reactions. We showed our experience in a 4 y survey, individualized by food allergens during the first two years of life. In Spain egg white protein is the most common allergen followed by cow's milk and peanuts. These three food items represent half of the sensitizations in children under 2 y of age. After 4 y sensitivities to vegetable allergens such as nuts, fruits and legumes are most frequent. The diagnosis of food allergy is still problematic, even in the case of atopy or IgE mediated hypersensitivity. There is a lack of standardized diagnostic procedures; the only test accepted as 'gold standard' for confirmation of food allergy and in general for food intolerance, is a properly performed double blind placebo-controlled oral food challenge. Negative results should be always followed by an open food challenge. This test should only be conducted in patients with a good medical condition and in a clinic or hospital setting, and only if trained personal and equipment for treating systemic anaphylaxis are present. Contraindications to a challenge test are limited to those situations that can be hazardous for the patient in relationship to the studied food. The treatment of food allergy and intolerance is avoiding the implicated food as long as necessary, until tolerance appears. Prevention of food allergy is the first goal of every pediatric allergologist. Controlled trials of food allergy prevention have been performed only in high allergic risk children.     

Food allergy knowledge,perception of food allergy labeling,and level of dietary practice: A comparison between children with and without food allergy experience

BACKGROUND/OBJECTIVESThe prevalence of food allergies in Korean children aged 6 to 12 years increased from 10.9% in 1995 to 12.6% in 2012 according to nationwide population studies. Treatment for food allergies is avoidance of allergenic-related foods and epinephrine auto-injector (EPI) for accidental allergic reactions. This study compared knowledge and perception of food allergy labeling and dietary practices of students.SUBJECTS/METHODSThe study was conducted with the fourth to sixth grade students from an elementary school in Yongin. A total of 437 response rate (95%) questionnaires were collected and statistically analyzed.RESULTSThe prevalence of food allergy among respondents was 19.7%, and the most common food allergy-related symptoms were urticaria, followed by itching, vomiting and nausea. Food allergens, other than 12 statutory food allergens, included cheese, cucumber, kiwi, melon, clam, green tea, walnut, grape, apricot and pineapple. Children with and without food allergy experience had a similar level of knowledge on food allergies. Children with food allergy experience thought that food allergy-related labeling on school menus was not clear or informative.CONCLUSIONTo understand food allergies and prevent allergic reactions to school foodservice among children, schools must provide more concrete and customized food allergy education.