What Is A Food Allergy?

A food allergy arises when the immune system incorrectly identifies a specific food or food component, typically a protein, as a harmful substance. This misidentification leads to the production of Immunoglobulin E (IgE) antibodies directly against the food protein. The subsequent activation of IgE triggers the release of histamine, resulting in an allergic symptom that can range from mild discomfort to severe, potentially life-threatening anaphylaxis (Sicherer & Sampson, 2017; Turner et al., 2014). 

How common are food allergies?  

Food allergies are a significant public health concern around the world, with their prevalence increasing globally. They affect up to 8-10% of the population (Warren et al., 2022). Food allergies are more common in children, impacting approximately 8% of children and 4% of adults in the United States (Gupta et al., 2019). 

The prevalence of specific food allergies can vary by region. However, the most common allergies typically include peanuts, which affect about 1-2% of the population in Western countries (ACAAI). Additionally, cow’s milk and egg allergies are prevalent in children, though many of these children eventually outgrow their allergies. 

Research suggests that several factors contribute to the rising incidence of food allergies, including changes in diet, environmental influences, and genetics (Sicherer & Sampson, 2017). 

How are food allergies diagnosed?

The gold standard for diagnosing food allergies is the oral food challenge. During this process, a patient consumes increasing amounts of a suspected allergen under close medical supervision to determine their threshold for allergic response (Mustafa et al., 2023). 

Blood tests can measure allergen-specific IgE antibodies related to specific foods (Ansotegui et al., 2020). 

A skin prick test is commonly performed by placing a small drop of an allergen extract on the skin, followed by a prick to assess whether an allergic reaction occurs, indicated by a raised bump that signifies an immediate response (Santos et al., 2023). 

Current management of food allergies

The primary treatment for food allergies has been strict avoidance of allergenic foods with individuals having epinephrine auto-injector available to treat a severe allergic reaction. Current treatment for desensitisation has been used such as oral immunotherapy (OTI) and sublingual immunotherapy (SLIT) to build up a tolerance of the allergen. There are emerging therapies currently being studied such as the Atopy Patch Test (Cocco & Solé, 2009).  

References 

Ansotegui, I. J., Melioli, G., Canonica, G. W., Caraballo, L., Villa, E., Ebisawa, M., Passalacqua, G., Savi, E., Ebo, D., Gómez, R. M., Sánchez, O. L., Oppenheimer, J. J., Jensen-Jarolim, E., Fischer, D. A., Haahtela, T., Antila, M., Bousquet, J. J., Cardona, V., Chiang, W. C., . . . Zuberbier, T. (2020). IgE allergy diagnostics and other relevant tests in allergy, a World Allergy Organization position paper. World Allergy Organization Journal, 13(2), 100080. https://doi.org/10.1016/j.waojou.2019.100080 

Cocco, R., & Solé, D. (2009). Patch test in the diagnosis of food allergy. Allergologia Et Immunopathologia, 37(4), 205–207. https://doi.org/10.1016/j.aller.2009.03.003 

Mustafa, S. S., Bress, J., Capucilli, P., Tuong, L. A., Denise-Sanchez-Tejera, N., Patrawala, S., & Ramsey, A. (2023). Outcomes of oral food challenges in a real-world setting, with predictors of outcomes. Annals of Allergy Asthma & Immunology, 131(5), 655–660. https://doi.org/10.1016/j.anai.2023.07.005 

Santos, A. F., Riggioni, C., Agache, I., Akdis, C. A., Akdis, M., Alvarez‐Perea, A., Alvaro‐Lozano, M., Ballmer‐Weber, B., Barni, S., Beyer, K., Bindslev‐Jensen, C., Brough, H. A., Buyuktiryaki, B., Chu, D., Del Giacco, S., Dunn‐Galvin, A., Eberlein, B., Ebisawa, M., Eigenmann, P., . . . Skypala, I. (2023). EAACI guidelines on the diagnosis of IgE‐mediated food allergy. Allergy, 78(12), 3057–3076. https://doi.org/10.1111/all.15902 

Sicherer, S. H., & Sampson, H. A. (2017). Food allergy: A review and update on epidemiology, pathogenesis, diagnosis, prevention, and management. Journal of Allergy and Clinical Immunology, 141(1), 41–58. https://doi.org/10.1016/j.jaci.2017.11.003 

Turner, P. J., Gowland, M. H., Sharma, V., Ierodiakonou, D., Harper, N., Garcez, T., Pumphrey, R., & Boyle, R. J. (2014). Increase in anaphylaxis-related hospitalizations but no increase in fatalities: An analysis of United Kingdom national anaphylaxis data, 1992-2012. Journal of Allergy and Clinical Immunology, 135(4), 956-963.e1. https://doi.org/10.1016/j.jaci.2014.10.021 

Warren, C. M., Agrawal, A., Gandhi, D., & Gupta, R. S. (2022). The US population-level burden of cow’s milk allergy. World Allergy Organization Journal, 15(4), 100644. https://doi.org/10.1016/j.waojou.2022.100644