Signs and Symptoms of Food Allergies

The signs and symptoms of a food allergy can range from mild and unconcerning (though uncomfortable) to significant and serious. While reactions are different for everyone, they classically begin within two hours of eating a trigger food.

Woman looking at allergic reaction in mirror

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Signs and symptoms of a food allergy tend to affect the skin, stomach, airways, eyes, or the entire body; common ones include rsh, swelling, upset stomach, breathing difficulty, and itchy eyes. In some cases, life-threatening anaphylaxis can occur.

Rather than assuming it is nothing, share these experiences with your healthcare provider to rule out or confirm food allergies (or, if you've already been diagnosed, to see if they are worsening or a new one has arisen). It's important that you know how to manage reactions if they occur, but also what to avoid and how to avoid it moving forward.

In contrast to food allergies, food sensitivity reactions—such as those related to lactose intolerance or celiac disease—may be delayed up to 12 hours

Skin Reactions

Food allergies can cause skin rashes, such as:

  • Hives: Raised red welts that can morph shape and change location all over the body; they look like mosquito bites and are itchy
  • Eczema: A scaly, itchy rash that may blister or peel
  • Swelling: Swollen tissue, especially around the face and lips

Discuss possible treatments for these skin irritants with your practitioner. Healthcare providers often suggest treating skin reactions with an oral antihistamine, such as Benadryl (diphenhydramine) or topical agents like steroid creams, calamine lotion, or oatmeal baths.

It also is important to take a close look at the hives and note whether they last for a short time or seem to be lasting longer than a few hours. This can help your healthcare provider to determine the cause of the hives. 

If your symptoms are primarily digestive, you should seek out a gastroenterologist to help you pinpoint the problem and find solutions.

Digestive Issues

Food allergies may cause stomach or intestinal symptoms—products of the way the body gets rid of the offending food. These can include:

  • Upset stomach/abdominal pain
  • Nausea
  • Vomiting
  • Diarrhea: Loose, watery stool more than three times a day

While a chronic stomachache may be a sign that you have a food allergy, it may be a sign of some other digestive issue. Lactose intolerance, celiac disease, inflammatory bowel disease (IBD), and ulcers are other conditions that may present similar symptoms. While antihistamines can help allergies, they do not help resolve the symptoms of these other conditions. 

If your symptoms are primarily digestive, you should seek out a gastroenterologist to help you pinpoint the problem and find solutions.

Breathing Trouble

A food allergy can affect the lungs, mouth and/or throat, any of which can impact your ability to breathe. If you have asthma and food allergies, you are at a higher risk for having a severe allergic reaction that involves trouble breathing. 

Food allergies that affect the airways are extremely serious and need to be handled immediately.

Some symptoms of allergies that affect the airways include:

  • Wheezing/high-pitched sound when trying to breathe
  • Coughing (due to an itchy throat or swelling)
  • Allergic rhinitis (runny nose)
  • Angioedema: Swelling of lips, tongue, eyes, or face
  • Trouble swallowing

Discuss with your healthcare provider how to treat mild swelling and/or a rash on your lips or tongue. For some people, oral antihistamines, such as Benadryl, are the course of treatment.

However, these symptoms can also be a sign of anaphylaxis (see below). Emergency medical treatment is needed in these cases.

Eye Reactions

Allergic reactions of the eyes fall under the term allergic conjunctivitis. Symptoms are:

  • Redness
  • Itching
  • Watering
  • Swelling

Talk to your healthcare provider about how to treat itchy, watery eyes. For many people, the use of an oral antihistamine will help resolve symptoms, though eye drops may be needed.

Anaphylaxis

Anaphylaxis is a type of shock caused by an allergic reaction. This type of reaction can happen within minutes of exposure to the allergen, although for some it may not occur for up to several hours. Due to the severity of this reaction, it is important not to ignore the first sign of one.

It may involve some or all of the symptoms outlined above (especially difficulty breathing), plus any of the additional reactions:

  • A sense of impending doom: Patients often report this feeling as they are overcome by the body's exposure to the allergen.
  • Dizziness, lightheadedness: This reaction is often due to a drop in blood pressure
  • Loss of consciousness: This reaction is also accompanied by low blood pressure and decreased heart rate.
  • Pale skin

If you or someone around you experiences any of the symptoms of anaphylaxis, call 911 immediately and administer first aid for anaphylaxis. Do not wait to see if symptoms improve.

Anaphylaxis can progress rapidly and can cause death within 30 minutes of the onset of symptoms if not promptly treated with emergency epinephrine. About 10 percent to 20 percent of the time, an individual experiencing an allergic reaction of this severity may even need a second dose of epinephrine to relieve symptoms.

Those who have been diagnosed with an anaphylactic allergy must always carry and use, if needed, an auto-injectable epinephrine dose.

Special Considerations for Children

It is important to recognize that children with food allergies may describe their symptoms differently than an adult might. They simply may not know the right words to describe how they feel.

For example, a child with food allergies may say something like “this is too spicy” or “my tongue feels thick” when they eat a trigger food. They also may become very fussy or irritable, experience stomach pain or diarrhea, and be unable to explain what is going on.

Babies and toddlers may only speak a few words altogether, if any, further stressing the need for caregivers to be on the lookout for potential allergy symptoms, which may be different in kids this age.

Again here, do not wait for symptoms to subside or worsen to react. Call 911 immediately if your child starts to experience facial, mouth or tongue swelling, or is experiencing trouble breathing.

If you are concerned that your child may have food allergies or be at risk for food allergies, talk to your pediatrician about seeing a board-certified allergist. 

Frequently Asked Questions

  • What are the most common food allergies?

    Around 90% of all food allergies involve eight foods: eggs, fish, milk, peanuts, shellfish, soy, tree nuts (for example, walnuts), and wheat. Among infants and children, the most common food allergies are eggs, milk, peanuts, soy, and wheat. Older kids and adults are most likely to be allergic to tree nuts, fish, and shellfish.

  • Is it possible to develop a food allergy as an adult?

    Absolutely. In fact, surveys conducted in 2015 and 2016 revealed surprisingly high rates of adult-onset food allergies. It's unclear what causes this to happen. One theory is exposure to an airborne allergen may sensitize an adult to a food. For example, adult-onset soy allergies have been triggered by pollen.

  • Is a food allergy the same as a food intolerance?

    No. A food allergy is a response by the immune system to a particular component of a certain food—usually a protein—which can result in symptoms such as hives or anaphylaxis. A food intolerance occurs when the digestive system is irritated by a particular food or is unable to break it down properly. Lactose intolerance is an example.

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10 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.
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