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Food Allergy

Food allergy is part of a larger group of adverse reactions to food. Food allergy is caused by an immune response that occurs after exposure to a specific food. When exposed, the immune system overreacts by producing antibodies called Immunoglobulin E (IgE) which ultimately cause an allergic reaction. The symptoms of an allergic reaction can include hives and itching or symptoms throughout the entire body (anaphylaxis) including difficulty breathing, low blood pressure and can be life-threatening. A recent study shows food allergy has increased by about 50% in children over the past 20 years and continues to increase. There are now about 6 million children in the U.S. with food allergy.

What Are the Most Common Food Allergens?

Individuals are most likely to be allergic to one or more of the top nine most common food allergens:

  • Cow milk
  • Egg
  • Peanut
  • Tree nuts (cashew and walnut, for example)
  • Soy
  • Wheat
  • Fish
  • Crustacean shellfish (shrimp and lobster, for example)
  • Sesame 

Learn more about the Top 9 Allergens.

When Do Food Allergies Typically Develop?

Food allergy most commonly starts in childhood. Not all food-related reactions are food allergy and, in fact, most rashes in childhood are not related to food. It often takes a detailed history and specific allergy testing to reach the diagnosis of food allergy. While some individuals may classify their food allergy as mild or severe, it is more important to know that any allergic reaction to food can cause a life-threatening condition called anaphylaxis, even if the reaction in the past was mild.

Can Food Allergies Be Prevented?

Current research-based findings indicate that most children should have the highly allergenic foods introduced early in life in age-appropriate forms. Early introduction will not guarantee the child will not develop the allergy, but it is the only preventive strategy currently available. If the child’s family has a strong history of allergy, some parents feel the need to see an allergist or have an allergy test prior to introducing the food. If allergy testing is to be done, it is often best done along with a thorough allergy evaluation by a specialist. Allergy testing prior to introduction of a food runs the risk of a false positive test, meaning the test says the child has allergy but this is not the case. False positive testing can unnecessarily restrict the child’s diet and cause undue stress.

What Can Cause a Food Allergy Reaction?

Food allergy reactions happen every time the individual is exposed to the allergen. The most common exposure is eating (ingesting the food). Exposure can also happen by inhaling steam from boiling the food, or cooking the food in an open pan such as scrambling a pan of eggs or frying fish. Steaming milk for coffee can also be an issue. Touching the food will most likely only cause a reaction in the area of contact but this is not always certain. Overall, it is likely best if the allergic individual does not touch their allergen.

Food Allergy Program at Lurie Children's

The first of its kind in Illinois, the Food Allergy Program seeks to improve the lives of children and families affected by food allergy. Our experts provide evaluation services and comprehensive treatment, including skin prick testing, food challenges, oral immunotherapy, and education on food avoidance and managing allergic reactions.

Learn more about the Food Allergy Program at Lurie Children's.

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