Understanding Food Allergy

The Basics

Food allergy is more than a reaction. It is the body learning the wrong lesson. To change food allergy, we must understand how the body learns to treat a normally harmless food as a threat. That immune alarm can affect the skin, gut, lungs, heart and circulation, and nervous system. The response can change from one exposure to the next.

What is food allergy?

The immune system protects the body from danger; but in food allergy, it treats a normally harmless part of a food, usually a protein, as a threat. That food component is called an allergen.

How an immediate reaction happens

In many immediate food allergies, the immune system makes antibodies called immunoglobulin E, or IgE, that recognize a particular food allergen. These antibodies attach to immune cells called mast cells and basophils. When the allergen binds to IgE on those cells, it can trigger the release of chemicals that cause allergic symptoms.

10%+

Of U.S. adults Have a Food Allergy1

8%

Of U.S. children Have a Food Allergy2

Of U.S. Children with a food allergy are allergic to more than one food3
42%

Of U.S. Children with a food allergy have experienced at least one severe reaction4

child receiving a cheek swab from doctor
Food allergy can take different forms

Some food-related allergic conditions involve different immune responses and develop more slowly. One example is eosinophilic esophagitis (EoE), which causes inflammation in the esophagus, the tube that carries food from the throat to the stomach. Food intolerance is different. It can cause some similar symptoms, but it does not involve the allergic immune response.

The FASI Lens

The gut, immune system, and nervous system work together to assess what enters the body. FASI investigates how this natural quality-control system can respond to harmless food as if it were dangerous.

Go Deeper Into The Biology
When the immune system sounds an alarm, an allergic reaction can affect the whole body.
What can a reaction look like?

Recognize the signs of an allergic reaction

A reaction can affect one part of the body or several at once. Symptoms may differ from one reaction to the next. Anaphylaxis is a severe, potentially life-threatening reaction that can worsen quickly.

Emergency Guidance: Epinephrine is the first treatment for anaphylaxis. If anaphylaxis is suspected, use prescribed epinephrine promptly, follow your emergency action plan, and seek emergency medical help. Antihistamines cannot replace epinephrine.
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Skin, face & mouth

Hives, itching, flushing or redness, or swelling of the lips, face, or tongue.

Gut

Nausea, vomiting, stomach pain, or diarrhea.

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Lungs & airways

Coughing, wheezing, throat tightness, or trouble breathing.

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Heart, circulation & nervous system

Dizziness, confusion, a sudden drop in blood pressure, or loss of consciousness.

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Diagnosis

How is food allergy diagnosed?

No single test tells the whole story. Diagnosis begins with a careful history. An allergist brings together your symptoms, medical history, and test results to determine whether you have a food allergy, check for related conditions, and help you choose a care plan.
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Start with what happened

Your clinician asks which food you ate, how much, how quickly symptoms appeared, what they were, and how they resolved.

Understand what tests can tell you

Skin-prick tests and blood tests for food-specific IgE can help. A positive result may show that your immune system recognizes the food, without proving that eating it will cause symptoms.

seeds and nuts background, natural food in wooden bowls, top view.

Use a food challenge when needed

If the diagnosis is still unclear, an allergist may recommend an oral food challenge: eating carefully measured amounts of the suspected food while a medical team watches for a reaction.

Important: Never attempt an oral food challenge at home.

Living with food allergy means living prepared

Daily management has two goals: reduce exposure to foods that trigger reactions and be ready if a reaction happens. This means reading labels, preventing accidental transfer of an allergen between foods (cross-contact), communicating with schools, caregivers, restaurants, and workplaces, carrying prescribed epinephrine, and keeping an emergency action plan up to date.

Preparation reduces risk, but uncertainty remains. Better treatments and continued research are essential.

Today’s treatments can reduce risk. They do not yet cure food allergy.

What treatments can do today

Today’s treatments serve different purposes. Epinephrine treats an emergency. Other treatments may make accidental exposure less likely to cause a reaction. An allergist can help you understand who each treatment is for, its benefits and risks, and what it would mean for daily life.

What it does

Epinephrine treats anaphylaxis. Prescribed options include an injection device or a nasal spray.

What to know 

It is used during an emergency. It does not prevent future reactions.

What it may do

For some people, oral immunotherapy (OIT) increases the amount of a food allergen needed to trigger a reaction.

How it works

Small, measured amounts of the allergen are swallowed regularly as part of a medical treatment plan. Dose increases take place under medical supervision.

What to know 

OIT can cause allergic reactions. Results vary, and continued treatment may be needed to maintain protection. It is not a cure.

What it may do

Omalizumab (Xolair®) is an antibody medicine given by injection. It can reduce the risk of allergic reactions after accidental exposure to one or more food allergens.

How it works

It targets IgE, the antibody involved in many immediate allergic reactions.

What to know 

 It is used alongside avoidance of foods that trigger your allergy and does not treat an emergency.

Important: Keep your care plan in place: No current treatment can guarantee that a reaction will not happen. Follow your clinician’s instructions about allergen avoidance and carry prescribed emergency medication.
GO DEEPER ON TODAY’S TREATMENTS

Hear how treatment is changing

CJ Beneduce

webinar

New Hope for Food Allergies
What is Changing in Treatment? with CJ Beneduce

Webinar

Biting Back at Allergies
The Allergy Equation: OIT and the Therapies Making It Possible with Wayne Shreffler

Webinar

OIT vs. SLIT vs. EPIT
A Pill, Drop, or Patch for Food Allergy? with Edwin Kim

The gap that FASI aims to close

Today’s care can identify food allergy, help families avoid triggers, and lower some risks. Yet tests cannot reliably predict how severe a future reaction will be. Treatments work differently for different people, and protection may depend on continued treatment.

Three questions drive our work: Why does food allergy begin? What drives reactions and keeps the disease active? Why does protection last in some people but fade in others?

Building on our foundation in discovery, FASI’s internal scientific leaders and global research network are tackling these questions together. Our goal is more precise diagnosis, new ways to prevent food allergy, and protection that lasts. We are driving the science to give families better options.

Explore the Questions
Funding

What We Fund

Our Mission

Our Impact on Food Allergy Research

Collaboration

Attend the FASI-10 Symposium

  1. National Institute of Allergy and Infectious Diseases, “Food Allergy.” ↩︎
  2. National Institute of Allergy and Infectious Diseases, “Food Allergy.” ↩︎
  3. Gupta RS et al., “The Public Health Impact of Parent-Reported Childhood Food Allergies in the United States,” Pediatrics, 2018 ↩︎
  4. Gupta RS et al., “The Public Health Impact of Parent-Reported Childhood Food Allergies in the United States,” Pediatrics, 2018 ↩︎