Food Allergies

What is food allergy?

A food allergy is an abnormal response of the body to a certain food. This is different from a food intolerance, which does not affect the immune system, although some of the same symptoms may be present.

What causes food allergy?

Before having a food allergy reaction, a sensitive child must have been exposed to the food at least once before. The child could also become sensitized through breast milk. At the time of the first exposure, the body makes a protective protein called an IgE antibody. This antibody will now activate every time the allergic food is eaten. The allergic symptoms will occur the second time your child eats the food. At that time, when IgE antibodies react with the food, histamines--a chemical compound that causes an inflammatory response in the body--are released. Histamines can cause your child to have hives, asthma, itching in the mouth, trouble breathing, stomach pains, vomiting, and/or diarrhea.

What is the difference between food allergy and food intolerance?

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

What foods most often cause food allergy?

Approximately 90% of all food allergies are caused by the following 8 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, tree nuts, fish, and shellfish commonly cause the most severe reactions. Between 4% and 8% of children under the age of 5 years have food allergies. From 1997 to 2011, the prevalence of reported food allergy increased 50% among children. Although most 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. The following are the most common symptoms of food allergy:

  • Nausea or vomiting

  • Diarrhea

  • Cramps

  • Hives

  • Swelling

  • Eczema

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

  • Trouble swallowing

  • Itching or tightness in the throat

  • Difficulty breathing or chest pain

  • Hoarse or squeaky voice (may slur words)

  • Loss of consciousness

  • Wheezing

  • Nasal congestion or runny nose

  • Sneezing

  • Slight, dry cough

  • Drop in blood pressure (feeling faint, weak, confused)

  • Weak pulse

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, trace amounts of peanut kernel can cause an allergic reaction for a severely peanut allergic individual.

The symptoms of food allergy may look like other problems or medical conditions. Always consult your child's doctor for a diagnosis.

Milk and soy allergy

Allergies to milk and soy are usually seen in infants and young children. Often, these symptoms are unlike the symptoms of other allergies, and may include:

  • Colic (fussy baby)

  • Blood in your child's stool

  • Poor growth

Often, your child's health care provider will change your baby's formula to a hypoallergenic one if it's thought he or she is allergic to milk.

The symptoms of a milk or soy allergy may look like other problems or medical conditions. Always consult with your child's health care provider for a diagnosis.

Treatment for food allergy

There is no medication to prevent food allergy. The goal of treatment is to avoid the foods that cause the symptoms. After seeing your child's health care provider and finding which foods your child is allergic to, 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 that your child is allergic to. Small amounts of the food allergen may be transmitted to your child through your breast milk and can cause a reaction.

It is also important to give vitamins and minerals to your child if he or she is unable to eat certain foods. Discuss this with your child's health care provider .

For children who have had a severe food reaction, your child's doctor may prescribe an emergency kit that contains epinephrine, which helps stop the symptoms of severe reactions. Consult your child's health care provider for further information.

Some children, under the direction of his or her health care provider, may be given certain foods again after 3 to 6 months to see if he or she has outgrown the allergy. Many allergies may be short-term in children and the food may be tolerated after the age of 3 or 4.

Prevention of food allergies

The development of food allergies cannot be prevented, but can often be delayed in infants by following these recommendations:

  • Your baby's only source of nutrition during their first 6 months of life should be breastmilk or formula. If possible, breastfeed your infant exclusively for the first 6 months.

  • If breastfeeding isn’t possible, a hydrolyzed formula may provide some protection against food allergies.

  • Gradually introduce solid foods to your baby at 7 months of age.

  • Introducing commonly allergenic foods early may also provide protection. Speak with your child’s health care provider about when and what types of foods to introduce.

Dining out with food allergies

If your child has 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 Dietetics Association offers these tips for dealing with food allergies when your family is 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 child's 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 your child is allergic to, along with additional information, such as a reminder to make sure all utensils and equipment used to prepare your meal are thoroughly cleaned prior to use. You can easily print these cards yourself using a computer and printer. If your child is eating out with friends and you are not going to be present, give your child a food allergy card (or make sure the adult in charge has one) to give to the server.

Alternately, there are several types of allergy cards available on the internet that can be customized with your child's 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.

Related Resources

American Academy of Allergy, Asthma & Immunology
Asthma and Allergy Foundation of America
Centers for Disease Control and Prevention
Food Allergy Initiative
Food Allergy Initiative
Food Allergy Initiative
Food Allergy Initiative
Food Allergy Initiative
FDA-Consumer Health Information
American Gastroenterological Association
National Institute for Allergy and Infectious Diseases
National Institute for Allergy and Infectious Diseases

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