Research Review 2012 August 15

This week’s research review focuses on Food Allergy

Food allergies affect up to 6% of young children and 3%-4% of adults. They encompass a range of disorders that may be IgE and/or non-IgE mediated, including anaphylaxis, pollen food syndrome, food-protein-induced enterocolitis syndrome, food-induced proctocolitis, eosinophilic gastroenteropathies, and atopic dermatitis. (Wang and Sampson 2011)

Inner city children have high rates of asthma and allergic rhinitis. Overall, 71% of the 228 patients evaluated for food allergy for any reason had evidence of IgE-sensitization to one food; 45% had sensitization to multiple foods. Sensitization occurred with the following frequencies: peanut 36%, egg 32%, milk 28%, tree nuts 22%, soy 18%, shellfish 18%, seeds 14%, wheat 13%, and fish 10%. Twenty-eight percent had food allergy (egg 18%, peanut 15%, milk 11%). High rates of food sensitization and allergy are seen in children for whom acute allergic reactions may not be the chief complaint. (Maloney, Nowak-Wegrzyn et al. 2011)

IgE-based testing continues to be the gold standard for suspected food allergies. Among modalities used by many conventional and alternative practitioners, immunoglobulin G (IgG)–based testing showed promise, with clinically meaningful results. It has been proven useful as a guide for elimination diets, with clinical impact for a variety of diseases. (Mullin, Swift et al. 2010)

A number of therapeutic strategies are under investigation targeting foods that most frequently provoke severe IgE-mediated anaphylactic reactions (peanut, tree nuts, and shellfish) or are most common in children, such as cow's milk and hen's egg. Diets containing extensively heated (baked) milk and egg represent an alternative approach. (Nowak-Wegrzyn and Sampson 2011)

Dr. Ron


Articles

Children in the inner city of New York have high rates of food allergy and IgE sensitization to common foods

            (Maloney, Nowak-Wegrzyn et al. 2011) Download

Testing for food reactions: the good, the bad, and the ugly

            (Mullin, Swift et al. 2010) Download

An increasing number of commercial tests for food allergies are marketed to consumers and healthcare practitioners with tenuous claims. The aim of this article is to provide an evidence-based review of the tests and procedures that currently are used for patients with suspected food allergy. A systematic review of the literature evaluating the validity of tests and procedures used in food reactions was performed using conventional search engines (eg, PubMed, Ovid) as well as consumer sites (eg, Google, Bing). The National Library of Medicine Medical Subject Headings (MeSH) term food hypersensitivity was used along with food allergy testing, food sensitivity testing, food intolerance testing, and adverse food reactions. Of the results obtained, testing for immunoglobulin E (IgE)-mediated food allergy was best represented in PubMed. IgE-based testing continues to be the gold standard for suspected food allergies. Among modalities used by many conventional and alternative practitioners, immunoglobulin G (IgG)-based testing showed promise, with clinically meaningful results. It has been proven useful as a guide for elimination diets, with clinical impact for a variety of diseases. Mediator release testing and antigen leukocyte cellular antibody testing were only represented on consumer sites. Further investigation into the validity and the clinical application of these tests and procedures is required. Disclosing the basis for food reactions continues to present a diagnostic challenge, and testing for food allergies in the context of an appropriate clinical history is paramount to making the correct diagnosis.


Future therapies for food allergies

            (Nowak-Wegrzyn and Sampson 2011) Download

Food allergy is an increasingly prevalent problem in westernized countries, and there is an unmet medical need for an effective form of therapy. A number of therapeutic strategies are under investigation targeting foods that most frequently provoke severe IgE-mediated anaphylactic reactions (peanut, tree nuts, and shellfish) or are most common in children, such as cow's milk and hen's egg. Approaches being pursued are both food allergen specific and nonspecific. Allergen-specific approaches include oral, sublingual, and epicutaneous immunotherapy (desensitization) with native food allergens and mutated recombinant proteins, which have decreased IgE-binding activity, coadministered within heat-killed Escherichia coli to generate maximum immune response. Diets containing extensively heated (baked) milk and egg represent an alternative approach to food oral immunotherapy and are already changing the paradigm of strict dietary avoidance for patients with food allergy. Nonspecific approaches include monoclonal anti-IgE antibodies, which might increase the threshold dose for food allergen in patients with food allergy, and a Chinese herbal formulation, which prevented peanut-induced anaphylaxis in a murine model and is currently being investigated in clinical trials. The variety of strategies for treating food allergy increases the likelihood of success and gives hope that accomplishing an effective therapy for food allergy is within reach.

Food allergy

            (Wang and Sampson 2011) Download

Food allergies affect up to 6% of young children and 3%-4% of adults. They encompass a range of disorders that may be IgE and/or non-IgE mediated, including anaphylaxis, pollen food syndrome, food-protein-induced enterocolitis syndrome, food-induced proctocolitis, eosinophilic gastroenteropathies, and atopic dermatitis. Many complex host factors and properties of foods are involved in the development of food allergy. With recent advances in the understanding of how these factors interact, the development of several novel diagnostic and therapeutic strategies is underway and showing promise.


References

Maloney, J. M., A. Nowak-Wegrzyn, et al. (2011). "Children in the inner city of New York have high rates of food allergy and IgE sensitization to common foods." J Allergy Clin Immunol 128(1): 214-5.

Mullin, G. E., K. M. Swift, et al. (2010). "Testing for food reactions: the good, the bad, and the ugly." Nutr Clin Pract 25(2): 192-8.

Nowak-Wegrzyn, A. and H. A. Sampson (2011). "Future therapies for food allergies." J Allergy Clin Immunol 127(3): 558-73; quiz 574-5.

Wang, J. and H. A. Sampson (2011). "Food allergy." J Clin Invest 121(3): 827-35.