Food Allergies: What Parents Need to Know

A food allergy happens when the body reacts against harmless proteins found in foods. The reaction usually happens shortly after a food is eaten. Food allergy reactions can vary from mild to severe.

Because many symptoms and illnesses could be wrongly blamed on "food allergies," it is important for parents to know the usual symptoms. The following is information from the American Academy of Pediatrics about food allergies and how to recognize and treat the symptoms. There is also important information about how to keep your child safe and healthy at home and in school if he has a food allergy.

Who gets food allergies?

A food allergy can happen at any age but occurs most often in infants and children younger than 6 years. It is estimated that 1 out of 20 to 25 children has a food allergy. Food allergies occur more often in children who have other allergies or who have family members with allergies.

What are the symptoms of a food allergy?

When the body's immune system overreacts to certain foods, the following symptoms may occur:

• Skin problems

  • Hives (red spots that look like mosquito bites)

  • Itchy skin rashes (eczema, also called atopic dermatitis)

  • Swelling

• Breathing problems

  • Sneezing

  • Wheezing

  • Throat tightness

• Stomach symptoms

  • Nausea

  • Vomiting

  • Diarrhea

• Circulation symptoms

  • Pale skin

  • Light-headedness

  • Loss of consciousness

If several areas of the body are affected, the reaction may be severe or even life-threatening. This type of allergic reaction is called anaphylaxis and requires immediate medical attention.

What is not a food allergy?

Food can cause many illnesses that are sometimes confused with food allergies. The following are not food allergies:

• Food poisoning—Can cause diarrhea or vomiting, but is usually caused by bacteria in spoiled food or undercooked food.

• Drug effects—Certain ingredients, such as caffeine in soda or candy, can make your child shaky or restless.

• Skin irritation—Can often be caused by acids found in such foods as orange juice or tomato products.

• Diarrhea—Can occur in small children from too much sugar, such as from fruit juices.

Some food-related illnesses are called intolerance, or a food sensitivity, rather than an allergy because the immune system is not causing the problem. Lactose intolerance is an example of a food intolerance that is often confused with a food allergy. Lactose intolerance is when a person has trouble digesting milk sugar, called lactose, leading to stomachaches, bloating, and loose stools.

Sometimes reactions to the chemicals added to foods, such as dyes or preservatives, are mistaken for a food allergy. However, while some people may be sensitive to certain food additives, it is rare to be allergic to them.

Which foods cause food allergies?

Any food could cause a food allergy, but most food allergies are caused by the following:

• Cow milk

• Eggs

• Peanuts

• Soy

• Wheat

• Nuts from trees (such as walnuts, pistachios, pecans, cashews)

• Fish (such as tuna, salmon, cod)

• Shellfish (such as shrimp, lobster)

Peanuts, nuts, and seafood are the most common causes of severe reactions. Allergies also occur to other foods such as meats, fruits, vegetables, grains, and seeds such as sesame.

Food allergies can be confusing. When a child is allergic to one type of food, such as peanuts (which is a type of bean), you may worry that she will also be allergic to other beans like soybeans or green beans. However, this is not always true. Most children allergic to peanuts tolerate other beans. In contrast, children allergic to cow milk are often allergic to goat milk, and children allergic to one type of shellfish, like shrimp, are likely to be allergic to other shellfish, such as crab and lobster.

How is a food allergy diagnosed?

If you think your child may have a food allergy, talk with your pediatrician. He or she will take a careful look at your child's symptoms and their relationship to foods. Sometimes the relationship is obvious. For example, if your child gets hives and lip swelling right after eating a walnut, it is likely a food allergy. Sometimes chronic health problems, like skin rashes or stomach problems, are caused by a food allergy, but it may be more difficult to know for sure. Many times causes other than food allergy must be considered.

If a food allergy is suspected, it is important to figure out which food(s) is the cause. This can be difficult if the allergic reaction occurred following a meal with many different foods. If your child has a chronic problem, such as skin rash or stomachaches, many foods in the diet must be looked at as possible causes.

There are blood tests to see if your child has a food allergy. Another type of test is a skin prick or scratch test. In this test, a small amount of the food is put into the skin by making a tiny, painless scratch on the skin. If your child is possibly allergic to the tested food, a small hive appears within minutes where the tiny scratch was made. If the tests are negative, they usually mean there is no food allergy. However, blood tests and skin tests are not perfect. It is possible to have a positive test and yet have no problems eating the food, and sometimes a negative test is found despite a true allergy.

Your pediatrician may refer you to an allergist. An allergist has specialized training in diagnosing and treating food allergies. The allergist can perform additional tests to see if a food allergy is the cause of your child's symptoms. If these tests do not clearly show a food allergy, the allergist may want to watch your child eat to see if the body reacts. This type of medical test is called a food challenge.

Severe allergic reactions

Anaphylaxis is a serious allergic reaction. It comes on quickly and can be fatal. It includes a wide range of symptoms that often happen quickly. Combinations of symptoms may occur. (See "What are the symptoms of a food allergy?") The most severe symptoms restrict breathing and blood circulation.

This type of reaction is a medical emergency and immediate medical attention is important. Anaphylaxis is treated with a medicine called epinephrine. This is a medicine given by an injection. (See "Emergency treatments.")

If your child experiences a severe allergic reaction to any food, inject epinephrine, if prescribed, and go to an emergency department or call 911 (or your local emergency number).

After an anaphylactic attack, your child needs to be seen by a doctor. It is important to find out exactly why the reaction happened so another one can be avoided. In most cases, the only way to prevent it from happening again is to avoid the cause. However, an evaluation by your pediatrician or an allergy specialist is important so that an action plan for prevention and treatment can be made.

(More information is available in the American Academy of Pediatrics brochure Anaphylaxis. )

How are food allergies treated?

The main way a food allergy is treated is to simply avoid the foods that cause the problems. However, it is also important to be ready to treat symptoms right away if your child accidentally eats the food. Children should be taught how to protect themselves by knowing which foods are off-limits. Teach your children to report any symptoms to an adult and, if appropriate for age, how to use emergency medicines.

Food allergy at school and camp

Whenever your child is away from you, whether it is at school, a child care center, or camp, there must be a plan to avoid problem foods, recognize and treat a reaction, and get medical care. Meet with staff early to set up an action plan. Here are some things to remember.

• Medical information. Give the school, child care center, or camp written medical information and instructions as directed by your doctor. Make sure that all staff who interact with your child understand his food allergy, can recognize symptoms of a reaction, and know what to do in an emergency.

• Medications. Provide the school, child care center, or camp with your child's medicines. Make sure his name is clearly marked on the medicine and that it is stored in an unlocked area (or carried by your child, if allowed). Designate school, child care, or camp staff who are properly trained to give your child his medicines.

• Contact information. Provide emergency contact information.

• Policies. Ensure that "no food sharing" policies are in place for your child. Have a plan for the school bus, such as no eating food on the bus. Do not forget to make arrangements for safe eating on school trips. Do not do crafts using foods.

• Have alternatives. Provide safe snacks for special occasions.

Will my child outgrow food allergies?

The good news is that food allergies are often outgrown during early childhood. It is estimated that 80% to 90% of egg, milk, wheat, and soy allergies go away by age 5 years. Some allergies are more persistent. For example, 1 in 5 young children will outgrow a peanut allergy and fewer will outgrow allergies to nuts or seafood. Your pediatrician or allergist can perform tests to track your child's food allergies and watch to see if they are going away.

Remember

Food allergies can be severe. Once your child has been diagnosed with a food allergy, it is best to avoid the problem foods. It is also important to have an action plan in the event of a reaction, and instruct anyone who cares for your child on how to help her. If you have any questions about your child's food allergies, talk with your pediatrician and allergist.

Products are mentioned for informational purposes only. Inclusion in this publication does not imply endorsement by the American Academy of Pediatrics (AAP).