Background True food Allergy is an immune system-mediated response to the foods we ingest. Symptoms may include reactions in skin, respiratory tract, cardiovascular system, gastrointestinal tract, eyes, and oral tissues. In the most serious cases, which are most often associated with peanuts, tree nuts and shellfish, symptoms may include difficulty breathing and anaphylaxis. Reactions generally occur within minutes to hours. Food Allergy should be distinguished from food intolerance, which may present similar symptoms, but is not an immunological reaction.
Incidence and Prevalence Many Americans believe they have food allergies, while in reality fewer than 1% of adults and 3% of children have true allergies. According to the National Institute of Allergy and Infectious Diseases (NIAID), the prevalence of food Allergy is increasing. Food Allergy causes roughly 30,000 episodes of anaphylaxis and 100 to 200 deaths per year in the United States alone.
Cause and Risk Factors Food allergies occur as immunologic responses to food proteins following the introduction of allergens through the digestive tract. After the immune system produces IgE antibodies against protein epitopes from the ingested food product, the IgE molecules are coated onto mast cells, which inhabit the mucosal lining of the digestive tract. Upon ingesting an allergen, the IgE reacts with its protein epitopes and release a number of chemicals (including histamine), which lead to oedema of the intestinal wall, loss of fluid, and altered motility, most frequently resulting in production of diarrhea. Food allergies deserve immediate attention and diagnosis, as any potentially has the ability to cause anaphylactic shock and a fatal reaction.