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How do food allergies work?

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Food allergies involve two features of the human immune response. One is the production of immunoglobulin E (IgE), a type of protein called an antibody that circulates through the blood. The other is the mast cell, a specific cell that occurs in all body tissues but is especially common in areas of the body that are typical sites of allergic reactions, including the nose and throat, lungs, skin, and gastrointestinal tract.

The ability of a given individual to form IgE against something as benign as food is an inherited predisposition. Generally, such people come from families in which allergies are common -- not necessarily food allergies but perhaps hay fever, asthma, or hives. Someone with two allergic parents is more likely to develop food allergies than someone with one allergic parent.

Before an allergic reaction can occur, a person who is predisposed to form IgE in response to foods has to be exposed to the food first. As this food is digested, it triggers certain cells to produce specific IgE in large amounts. The IgE is then released and attaches to the surface of mast cells. The next time the person eats that food, it interacts with specific IgE on the surface of the mast cells and triggers the cells to release chemicals such as histamine. Depending upon the tissue in which they are released, these chemicals will cause a person to have various food allergy symptoms. If the mast cells release chemicals in the ears, nose, and throat, a person may feel an itching in the mouth and may have trouble breathing or swallowing. If the affected mast cells are in the gastrointestinal tract, the person may have abdominal pain, vomiting, or diarrhea. The chemicals released by skin mast cells, in contrast, can prompt hives.

From: Food Allergy and Food Intolerance WebMD Medical Reference

SOURCES:

The National Institute of Allergy and Infectious Diseases: "Fact Sheet: Food Allergy and Intolerances."  UpToDate. American Academy of Allergy Asthma & Immunology.

Reviewed by Brunilda Nazario on October 29, 2018

SOURCES:

The National Institute of Allergy and Infectious Diseases: "Fact Sheet: Food Allergy and Intolerances."  UpToDate. American Academy of Allergy Asthma & Immunology.

Reviewed by Brunilda Nazario on October 29, 2018

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