Allergens: Food

What is food allergy?

A food allergy is an abnormal response of the body to a certain food. It is important to know that this is different than a food intolerance, which does not affect the immune system, although some of the same signs may be present.

What causes food allergy?

Before having a food allergy reaction, a sensitive person must be exposed to the food at least once before. It is the second time the person eats the food that the allergic symptoms happen. At that time, when IgE (Immunoglobulin E) antibodies react with the food, histamines are released, which can cause hives, asthma, itching in the mouth, trouble breathing, stomach pains, vomiting, or diarrhea.

What is the difference between food allergy and food intolerance?

Food allergy causes an immune system response, causing symptoms that range from uncomfortable to life-threatening. Food intolerance does not effect the immune system, although some symptoms may be the same as in food allergy.

What foods most often cause food allergy?

Approximately 90 percent of all food allergies are caused by eight foods:

• Milk

• Eggs

• Wheat

• Soy

• Tree nuts

• Peanuts

• Fish

• Shellfish

Eggs, milk, and peanuts are the most common causes of food allergies in children, with wheat, soy, and tree nuts also included. Peanuts, nuts, fish, and shellfish commonly cause the most severe reactions. Nearly 5 percent of children under age 5 years, and 18 percent under age 18, have food allergies. Although many children "outgrow" their allergies, allergy to peanuts, tree nuts, fish, and shellfish may be lifelong.

What are the symptoms of food allergy?

Allergic symptoms may begin within minutes to an hour after ingesting the food. Symptoms may include:

• Vomiting

• Diarrhea

• Cramps

• Hives

• Swelling

• Eczema

• Itching or swelling of the lips, tongue, or mouth

• Itching or tightness in the throat

• Difficulty breathing

• Wheezing

• Lowered blood pressure

• Hives

• Eczema

• Asthma

According to the National Institute of Allergy and Infectious Disease, it does not take much of the food to cause a severe reaction in highly allergic people. In fact, as little as 1/44,000 of a peanut kernel can cause an allergic reaction for severely allergic individuals.

Treatment for a food allergy in adults

Specific treatment for food allergy will be determined by your physician based on:

• Your age, overall health, and medical history

• Extent of the disease

• Your tolerance for specific medications, procedures, or therapies

• Expectations for the course of the disease

• Your opinion or preference

At this time, no medication is available to prevent food allergy. The goal of treatment is to avoid the food that causes the symptoms.

If you have a food allergy, you should carry, and know how to administer, injectable epinephrine to treat emergency reactions. People with food allergy must be prepared to treat any accidental ingestion of the foods that cause the allergic reaction. Discuss this further with your physician.

There are medications available to treat some symptoms of food allergy after the food has been eaten. These medications may relieve rhinitis symptoms, gastrointestinal symptoms, or asthma symptoms. Discuss this further with your physician.

Although research is ongoing, currently, there is no allergy injection treatment approved for the treatment of food allergies. Strictly avoiding the allergy-causing food is the only way to prevent a reaction.

Treatment of food allergies in children

After seeing a physician and identifying the foods to which your child is allergic, it is very important to avoid these foods and other similar foods in that food group. If you are breastfeeding your child, it is important to avoid foods in your diet to which your child is allergic. Small amounts of the food allergen may go to your child through the breast milk and cause a reaction.

It is also important to give vitamins and minerals to your child if he/she is unable to eat certain foods. Discuss this further with your physician.

For children who have had an allergic reaction to a food, your physician may prescribe an emergency kit that contains epinephrine, which helps stop the symptoms of severe reactions. Discuss this further with your physician.

Dining out with food allergies

If you have one or more food allergies, dining out can be a challenge. However, it is possible to have a healthy and satisfying dining-out experience; it just takes some preparation and persistence on your part.

The American Dietetic Association offers these tips for dealing with food allergies when you are eating away from home:

• Know what ingredients are in the foods at the restaurant where you plan to eat. When possible, obtain a menu from the restaurant ahead of time and review the menu items.

• Let your server know from the beginning about your food allergy. He or she should know how each dish is prepared and what ingredients are used. Ask about preparation and ingredients before you order. If your server does not know this information or seems unsure of it, ask to speak to the manager or the chef.

• Avoid buffet-style or family-style service, as there may be cross-contamination of foods from using the same utensils for different dishes.

• Avoid fried foods, as the same oil may be used to fry several different foods.

Another strategy for dining out with food allergies is to give your server or the manager a food allergy card. A food allergy card contains information about the specific items you are allergic to, along with additional information, such as a reminder to make sure all utensils and equipment used to prepare your meal is thoroughly cleaned prior to use. You can easily print these cards yourself using a computer and printer.

Alternately, there are several types of allergy cards available on the internet that can be customized with your personal information. One example is the "Food Allergy Buddy" Dining Card, promoted by the National Restaurant Association.

The Food Allergy Initiative, in conjunction with the National Restaurant Association and the Food Allergy and Anaphylaxis Network, has developed the Food Allergy Training Program for Restaurants and Food Services. This training program was developed to help restaurants and other food service outlets to ensure their customers, including those with food allergies, will receive a safe meal prepared to customer specifications.