Food Allergies and Treatments
Written by Amanda Wattson, MD   
Thursday, 15 October 2009
A food allergy is an abnormal response of the immune system that is caused by the protein in certain foods. A food allergy is not the same as food intolerance. A person with food intolerance may have symptoms, such as abdominal distress, after eating a certain food. However, this response is not caused by the immune system.
What is going on in the body?

A food allergy occurs when an immune response occurs. An immune response is a normal response of the body to something it sees as abnormal. Usually the response is to bacteria, viruses, and toxins. Sometimes the body will recognize certain foods as abnormal. When foods are recognized as abnormal, the body produces an antibody known as IgE. IgE reacts with mast cells, which are part of the immune system. The reaction affects mast cells in many areas of the body, including the following:
- lungs
- nose and throat
- skin
- stomach and bowels

When the IgE reacts with the mast cells, histamine is produced. This chemical produces the symptoms of a food allergy.
What are the causes and risks of the condition?

A food allergy is an abnormal immune system response to protein in certain foods. Following are some of the foods that commonly cause food allergies:
- eggs
- fish
- milk and other dairy products
- peanuts and peanut oil
- shellfish, such as shrimp and crab
- soy
- tree nuts, such as walnuts
- wheat
- whitefish

There is some evidence that genetically modified corn, known as StarLink, may cause severe allergic responses. This possibility is currently being investigated. Most people with food allergies also have other allergy-related disorders. These include nasal allergies to dust and pollen, eczema, and asthma.

What are the treatments for the condition?

Foods that cause an allergic response should be eliminated from the diet. It is important to read food labels carefully. Peanuts and milk, for example, are in many prepared foods.

Following are some of the medications used to treat an allergic response:
- antihistamines to block the mast cell reaction that causes symptoms
- bronchodilators to open tight airways
- corticosteroids to reduce the immune response
- epinephrine to minimize the allergic response and prevent anaphylaxis

People with severe food allergies may carry either an EpiPen or an Ana-Kit. These are devices containing epinephrine to prevent anaphylaxis. These devices can be used by the person or a bystander to inject the medication.
What are the side effects of the treatments?

Bronchodilators and epinephrine raise the heart rate and blood pressure. Antihistamines can cause drowsiness and dry mouth. Corticosteroids may increase the risk for infection.
What happens after treatment for the condition?

Most individuals who have food allergies have them for their entire lives. Some children may outgrow food allergies. Food allergies can lead to dietary restrictions that may cause malnutrition if the restrictions are severe. Individuals with food allergies may have an overall change in normal lifestyle. The individual should wear a medical alert bracelet identifying the allergy.