Nutrition • Mar 23, 2010

Food Allergies in Children

Although food allergies tend to be over-diagnosed, about 5% of children have true allergies to foods. Allergic children produce antibodies against certain foods. When these antibodies come in contact with the allergenic food, the reaction releases numerous chemicals that cause the symptoms.


The following three characteristics signal food allergies in children:

  1. Allergic symptoms within 2 hours of eating certain foods. The most common reactions involve the mouth (like swelling), gastrointestinal tract (like vomiting or diarrhea), and skin (like hives or a rash). Rarely, a child has a severe allergic anaphylactic reaction that may be life-threatening. Such reactions include a rapid onset of difficulty breathing, difficulty swallowing, or a fall in blood pressure.
  2. Your child has other allergic conditions such as eczema, asthma and hay fever. These children have a much higher rate of associated food allergies than nonallergic children.
  3. Other family members (parents or siblings) have food allergies. Food allergies are often inherited. Sometimes a child is allergic to the same food as the parent.

At least half of the children who develop a food allergy during the first year of life outgrow it by 2 or 3 years of age. Some food reactions, such as to milk, are more commonly outgrown than the others. Less than 1% of infants with a cow’s milk allergy develop a lifelong allergy to milk. Allergies to peanuts, tree nuts, and shellfish (shrimp, crab, and lobster) often persist for life.


Common symptoms include swelling of the lips, tongue or mouth, diarrhea or vomiting, hives and/or itchy red skin. Less common symptoms are a sore throat or throat discomfort, nasal congestion, sneezing or sniffing. An occasional child with asthma, migraine headaches, colic or recurrent abdominal pain may have some attacks triggered by food allergies. These children also have some of the typical symptoms of food allergies.


Overall, the most allergy-causing food is the peanut. An estimated 400,000 school-age children have peanut allergies. Experts say the number is growing quickly. In fact, between 1997 and 2002, peanut allergies in kids under age 5 doubled. The following five foods account for over 80% of food reactions: peanuts, eggs, cow’s milk products, soybeans (and soy formula) and wheat. These five foods along with fish, shellfish and tree nuts account for over 95% of food reactions.


  1. Keep a diary of symptoms and recently eaten foods for at least 2 weeks. Symptoms may vary depending on the amount of food consumed.
  2. Eliminate the suspected food from the diet for 2 weeks. If this is the correct (allergy-causing) food, most symptoms will improve within 2 days. Almost all of them will improve by 1 week of avoiding the allergic food.
  3. Re-challenging your child with the suspected food produces the same symptoms. Always call your doctor before doing this. NEVER attempt this if your child has experienced a severe or anaphylactic reaction to a food.


  1. Avoid the allergy-causing food. Talk to a nutritionist for replacement options.
  2. Consider avoiding other foods in that food group or foods that cross-react to other allergens. The most common cross-reaction involves children allergic to ragweed. They commonly react to watermelon, cantaloupe or other foods in the gourd family. Children allergic to peanuts may rarely cross-react with soybeans, peas, or other beans. Surprisingly, most tree nuts are unrelated to each other and do not cross-react with peanuts.
  3. Provide substitutes for any missing vitamins or minerals. This is especially important if a major food group (such as milk products) is eliminated which will lead to calcium and vitamin D deficiency unless appropriate supplements are given.
  4. Give Benadryl for hives up to 4 times a day in the appropriate dosage if hives or itching is the only symptom.
  5. Talk to your pediatrician about a referral to an Allergist for further testing and management options before permanently eliminating a food from the diet.
  6. If a child has had a severe or anaphylactic reaction to a food, that food should be avoided for the rest of the life, never rechallenge a child with that food and keep an emergency kit with an epinephrine-loaded syringe at home, at school, and in the car. Talk to your doctor in order to get a prescription for the Epi-pen.
  7. High risk or allergy-prone children have siblings or parent/s with asthma, eczema, severe hay fever or documented food allergies. In these children, the onset of allergies may be delayed by being somewhat careful about their diet. If possible, they should be breastfed in the first year of life. Try to avoid milk products, eggs, peanut butter, soy protein, fish, wheat and citrus fruits during the entire first year of life. It may be prudent to avoid peanuts and fish until 2 years of age.


  1. Call your doctor immediately if your child develops widespread hives, swelling or itching, recurrent vomiting or other persistent symptoms related to food allergy.
  2. Call 911 immediately if your child develops any serious symptoms such as difficulty breathing, wheezing, croupy cough, passing out, difficulty swallowing, or chest tightness.