A food allergy is an adverse reaction that occurs from the ingestion of food or a food ingredient such as a coloring or preservative. When an allergenic food (antigen) triggers an antibody immunoglobulin E (IgE) response, IgE binds to white blood cells (mast cells and basophils) and causes the release of histamine, which leads to swelling and inflammation.
Most symptoms of food allergies occur within a few minutes to an hour of consuming food. A food allergy can initially be experienced as an itching in the mouth or difficulty swallowing and breathing. Then, during digestion of the food in the stomach and intestines, symptoms such as nausea, vomiting, diarrhea, and abdominal pain can arise.
When allergens are absorbed and enter the bloodstream they can reach the skin and induce hives or eczema, and when they reach the airways, they can cause asthma. As the allergens travel through the blood vessels, they can cause lightheadedness, weakness, and a sudden drop in blood pressure. Anaphylactic reactions can occur and can be severe even if they start off with mild symptoms, such as a tingling in the mouth and throat or discomfort in the abdomen. They can be fatal if not treated quickly. Known food allergens should always be avoided. Read more