Food Allergy Testing
Food allergy testing helps determine if your symptoms are caused by an immune system overreaction to specific foods, which can range from mild discomfort to life-threatening anaphylaxis.
Overview
A food allergy happens when your immune system—your body's defense against germs—overreacts to a certain food as if it were harmful. If you have symptoms after eating, testing can help identify if an allergic reaction is the cause. Most food allergies are triggered by:
- Milk
- Eggs
- Peanuts
- Tree nuts (including almonds, walnuts, pecans, and cashews)
- Soy
- Wheat
- Fish
- Shellfish
Food allergies are more common in children, though most children grow out of allergies to milk, egg, soy, and wheat. If an allergy begins in adulthood, it is likely to persist for life.
What is it used for?
Testing is used to confirm if you have a true food allergy versus a food intolerance or food sensitivity. While intolerances (such as lactose intolerance or gluten sensitivity) generally affect only digestion and are not life-threatening, food allergies involve the immune system and can affect the whole body.
Why do I need food allergy testing?
You may need testing if you experience symptoms within minutes to hours of eating, or if you have been diagnosed with eosinophilic esophagitis (EoE). Symptoms may include:
- Nausea, vomiting, or diarrhea
- Stomach pain
- Tingling in the mouth
- Skin reactions (hives, itching, or rash)
- Coughing or nasal congestion
Seek emergency medical help (call 911) immediately if you experience symptoms of anaphylaxis, which include trouble breathing, dizziness, fainting, swelling of the tongue or throat, rapid heart rate, or cold, clammy, pale skin.
What happens during testing?
An allergist will review your medical history before selecting the appropriate test:
- Skin prick test: A liquid containing a food protein is placed on the skin, which is then pricked. A red, itchy bump indicates a potential allergy.
- Allergy blood test: Measures immunoglobulin E (IgE) antibodies in your blood. Higher levels may indicate an allergy, though this test is often used alongside others.
- Oral food challenge test: Considered the most accurate test, you eat small, increasing amounts of a suspected food under medical supervision to watch for a reaction.
- Food elimination diet: You remove suspected foods from your diet for about two weeks and reintroduce them one at a time to monitor for symptoms. This should not be done if you have a history of serious allergic reactions.
Management
There is no cure for food allergies. Management involves strictly avoiding trigger foods and reading labels carefully. For severe allergies, an allergist may prescribe an autoinjector containing epinephrine for emergency use.