Health Information

Food Allergies

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 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, or could also be sensitized through breast milk. It is the second time your child eats the food that the allergic symptoms happen. At that time, when IgE antibodies react with the food, histamines are released, which can cause your child to experience 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 percent of all food allergies in children are caused by the following 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, tree nuts, fish and shellfish commonly cause the most severe reactions. Nearly 5 percent of children under the age of five years have food allergies. From 1997 to 2007, the prevalence of reported food allergy increased 18 percent among children under age 18 years. Although most children "outgrow" their allergies, allergy to peanuts, tree nuts, shellfish, and fish 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. However, each child may experience symptoms differently. 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

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.

The symptoms of food allergy may resemble other problems or medical conditions. Always consult your child's doctor 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 doctor 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 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 doctor.

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

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