What Are Food Allergies?

In This Article
Table of Contents

Food allergies occur when your body mistakenly identifies and treats an ingested food as a threat, initiating an immune system response. Even eating a tiny amount of the offending food can trigger an allergic reaction, which may involve anything from hives or eczema to swollen lips, stomach troubles to difficulty breathing, and even death.

Overall, food allergies are relatively common and impact approximately 32 million Americans, including 5.6 million children under the age of 18. That equates to one in 13 children, or roughly two kids per classroom. While food allergies tend to run in families, doctors are not yet able to predict who will develop food allergies and who will not.

Food Allergy Symptoms

People with food allergies report abnormal sensations in their mouth, tongue, and throat during a reaction. These symptoms are sometimes described in the following ways:

  • Funny feeling of the tongue or mouth (for instance, a poking, jabbing, itchy, or heavy feeling, or as if there is hair present)
  • Feeling like something is stuck in the throat
  • Feeling of heaviness or thickness in the throat
  • Feeling of a bump in throat

The most common symptoms of a food allergy include:

  • Tingling or itching in the mouth
  • Hives, itchy skin, or eczema
  • Stomach cramps, nausea, or vomiting

More serious symptoms include:

  • Swelling in the lips, face, or tongue
  • Wheezing, trouble breathing, or nasal congestion
  • Dizziness, fainting, or lightheadedness

Most people assume that they do not have to worry if they have a mild response to a particular food. But sometimes allergic reactions to food increase in intensity over time.

The most serious reaction to a food allergen is anaphylaxis. This life-threatening allergic reaction can significantly impact your ability to breathe, drop your blood pressure, and alter your heart rate.

Anaphylaxis can occur within minutes of exposure to the trigger food and, in some cases, be fatal. For this reason, people with food allergies need to be very diligent about what they eat and carry any medications prescribed by their doctor with them at all times.


Like any other allergy, a food allergy happens because the body has a negative response to a substance it is exposed to—in this case, food (or more precisely, in most cases, proteins in food).

Your immune system stands ready to fight any substances that it deems could be harmful to you. It does this by producing immunoglobulin E (IgE) antibodies that prompt cells to release chemicals to combat the "intruders." With a food allergy, your body misinterprets something you eat or drink as being an enemy worthy of attack, despite the food or beverage being perfectly harmless. The result is an allergic reaction.

More than 90% of food allergies are caused by proteins in eight different foods. These include:

  • Milk: A food allergy to milk is caused by the proteins contained in casein and whey. This allergy is different from lactose intolerance, which is due to an inability to digest carbohydrate in milk rather than an allergy. Milk allergy is typically diagnosed in the first year of life, but most children outgrow it by age 5. It is the most common food allergy in American children.
  • Eggs: Egg allergy is the second most common food allergy among kids. More than 80% of kids will outgrow egg allergy before age five. Some also may have a reaction to hidden egg ingredients.
  • Soy: Soy allergy is generally mild, and most children outgrow it in the first few years of life. However, reactions can be severe, and children allergic to soy often have a milk allergy as well.
  • Wheat: One in five children allergic to wheat also will have an allergy to another grain. Most children outgrow this food allergy in the first few years of life. It is uncommon for adults to be allergic to wheat.
  • Peanuts: This food allergy is generally considered much more serious because rates of anaphylaxis are greater than with other food allergies. One in four people with a peanut allergy also have a tree nut allergy.
  • Tree nuts: Because this food allergy often coexists with a peanut allergy, you also will need to avoid peanuts if this affects you. While you can be allergic to just one tree nut, it is generally recommended that you avoid all tree nuts including walnuts, pecans, pistachios, hazelnuts, and almonds. Although many kids are born with this food allergy, people who have never had an issue with nuts may develop an allergy to tree nuts later in life.
  • Fish: This food allergy is more likely to develop as an adult. The most common offenders are salmon, tuna, and halibut. Like tree nuts, you can have an allergy to one fish and not others, but generally it is recommended that you avoid all fish.
  • Shellfish: Similar to fish allergy, a shellfish allergy is more common in adults. Both crustaceans and mollusks can be problematic. These reactions tend to be severe. While you can have a reaction to only one kind of shellfish, it is generally recommended that you avoid all shellfish. Thus, if you have a shellfish allergy, you need to avoid shrimp, crab, lobster, clams, oysters, mussels, and scallops.


Your allergist will ask you very detailed questions about what you ate before the reaction occurred, the specific symptoms experienced, and when the symptoms occurred in relation to when the food was ingested.

Your doctor also may order blood tests such as IgE levels or RAST tests. Specific testing for allergy to certain foods can be done with skin prick tests. These tests provide insight into your symptoms, which your doctor may use combined with your symptoms and food diary to make a diagnosis.

Keep in mind though, that according to the American College of Allergy, Asthma and Immunology, an oral food challenge is the only test that confirms a food allergy. Oral food challenges are typically used when other testing is inconclusive, or to determine if a food allergy has been outgrown.


First and foremost, if you have a confirmed food allergy, you need to eliminate all the offending foods from your diet, as well as any foods made with or containing those ingredients. Medication can be used to ease symptoms and to address a severe allergic reaction.

Diet Diligence

Start reading the labels on everything you eat and ask about ingredients at restaurants. Also, never assume that a food is safe. Food allergens may be present in the most unlikely foods (and self-care products). For instance, chili may contain peanut butter and Vodka may contain tree nuts.

You also need to know where your food comes from and what it comes into contact with. For example, even though a dish at a restaurant may seem safe, it may be prepared on the same surface as meals containing the food you are allergic to. The same goes for foods produced or packaged in larger plants.

The Food Allergy Labeling and Consumer Protection Act requires that food products be labeled in plain language—"contains milk," "contains soy"—to communicate ingredients. Many labels also warn of possible cross-contamination issues.


Most of the time, mild allergic reactions such as itching, sneezing, hives, and rashes can be treated with antihistamines such as Benadryl. Your doctor also may prescribe oral steroids if you have a more severe allergic reaction to a food.

The most serious reaction to food allergy, anaphylaxis, must be treated with an injection of epinephrine and a follow up visit to the ER. As a result, most people with food allergies carry an EpiPen everywhere they go. If you are given a prescription for an EpiPen, make sure that you know how to appropriately administer the medication using an epinephrine injector. It could save your life.


Most parents of young children wonder if they can prevent food allergies from occurring in their children.

Recent studies show that early introduction of highly allergenic foods, especially in at-risk populations, can decrease the incidence of food allergy. Therefore, as early as 2008, the American Academy of Pediatrics recommended exclusive breastfeeding for the first 4-6 months of life, then the slow introduction of solid foods without regard to food allergy concerns. Discuss a plan with your doctor to determine the best route for your family.

Can a Food Allergy Be Outgrown?

Children can outgrow their food allergies, but doing so depends on a number of factors. Peanut, tree nut, fish, and shellfish allergies tend to be lifelong, while children tend to outgrow milk, soy, egg, and wheat food allergies. Overall, a low food specific IgE level seems to indicate a better chance of outgrowing an allergy. Also, having few, if any, serious reactions to a known food allergen also may help predict who will outgrow their food allergies.


When you or your child are learning to deal with a food allergy, there is some adjustment that must take place. Not only do you need to learn how to live with a food allergy, but you also need to learn how to cope with some of the negative feelings and emotions that come with a food allergy.

It is not uncommon to feel a sense of loss when you are dealing with a food allergy. What's more, you also may struggle with anger, frustration, anxiety, and fear. Some people have even reported going through what feels like the stages of grief until accepting that this diagnosis is now a part of their everyday life.

Overall, the best way to deal with a food allergy is to learn as much as you can about the diagnosis.

Then, take the appropriate precautions in order to keep yourself or your child safe. Once you know how to do that, you should be able to live a relatively normal life in spite of your allergies.

A Word From Verywell

While avoiding particular food allergens can seem challenging at first, food allergies do not have to rule your life. While it is normal to feel scared, frustrated, or overwhelmed at the beginning, the new routines and systems you implement to stay safe will become routine and manageable.

Was this page helpful?
Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food Allergy Research and Education (FARE). Facts and Statistics

  2. Zukiewicz-sobczak WA, Wróblewska P, Adamczuk P, Kopczyński P. Causes, symptoms and prevention of food allergyPostepy Dermatol Alergol. 2013;30(2):113-6. doi:10.5114/pdia.2013.34162

  3. Tupper J, Visser S. Anaphylaxis: A review and update. Can Fam Physician. 2010;56(10):1009-11.

  4. American College of Allergy, Asthma and Immunology. Food Allergy Diagnosis. Updated February 12, 2019.

Additional Reading