MASTERING FOOD ALLERGY:  DEFINING FOOD ALLERGY AND IT’S NATURAL COURSE (Agnes M. Gonzalez-Andaya, M.D.)

Food allergy is an abnormal immunologic response to food proteins.  About 6% of children less than 3 years of age and 2% of the adult population experience food allergy.  In the Philippines , the most common food allergens are cow milk, egg and fish in children < 2 years old and fish and shellfish in adults.. 

The vast majority of food proteins are tolerated through suppression or tolerance. Recent studies suggest that antigen-presenting cells, dendritic cells and regulatory T cells play a central role. Regulatory T cells suppress immune responses through IL-4, IL-10 and TGF-β which favor the generation of tolerance.  Several factors, including antigen properties, route of exposure, and genetics and age of the host contribute to the development of oral tolerance.

Food allergy are responsible for a variety of symptoms involving the skin, gastrointestinal tract, and respiratory tract and may be caused by IgE-mediated and non-IgE-mediated mechanisms.
Over time, most food allergy (eg. cow milk, egg and peanut in 20%) is lost, although allergy to some foods (eg.. tree nuts, fish, shellfish and seeds)  is usually not out-grown.  Several factors, including, small skin test size and low food-spIgE levels have been associated with the development of tolerance while the presence of other atopic diseases and higher concentration of spIgE reduced the chance of achieving tolerance.