Food Allergy

What is a food allergy?

A food allergy is an abnormal response to a certain food. If your child has a food allergy, exposure to that food causes an immune system response, leading to symptoms that range from uncomfortable to life-threatening. Often, an allergic reaction will occur the second time your child is exposed to a particular food. However, in some cases, your child could be sensitized to a food through breast milk.

Ninety percent of food allergies are caused by the following six foods: milk, eggs, wheat, soy, tree nuts, and peanuts. Eight percent of children under age 6 have food allergies.

What are the symptoms of a food allergy?

Symptoms may begin anywhere from a few minutes to an hour after your child ingests the food. Common symptoms include:

  • vomiting
  • diarrhea
  • cramps
  • hives
  • swelling or rash
  • eczema
  • itching or swelling of the lips, tongue, or mouth
  • itching or tightness in the throat
  • difficulty breathing
  • wheezing
  • lowered blood pressure

The symptoms can be different for milk allergies and soy allergies, which are often seen in infants and young children. The symptoms may include:

If a milk allergy is suspected, your doctor may change your baby’s formula to a soy formula. If your baby has problems with soy formula, your child’s physician may suggest a hypoallergenic formula.

Many children do outgrow their allergies, but allergies to peanuts, tree nuts, fish, and shellfish may last a lifetime.

What causes food allergies?

A food allergy occurs when the body's immune system identifies a food as harmful, triggering an allergic reaction. According to the National Institute of Allergy and Infectious Diseases, even a small amount of the food can cause a severe reaction in a highly allergic child.

How we care for food allergies

At Boston Children’s Hospital, our allergists provide diagnostic evaluations for food allergies that are supported by our advanced allergy testing facilities. Once an allergy is diagnosed, our allergists create an individual treatment plan for each child. Treatment may include education, medical management, and coordinated care with your child’s primary physician.