What Are the Symptoms of a Peanut Allergy?

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Peanut allergies are a major cause of severe symptoms in children and adults. Even a tiny amount of peanut protein can set off a severe reaction in allergic individuals.

The prevalence of peanut allergies has tripled over the last two decades, with as many as 2.5% of children having a confirmed peanut allergy. Even if you or your child experiences only mild symptoms after eating peanuts, it's essential to contact your healthcare provider for proper diagnosis and treatment.

This article discusses everything you need to know about peanut allergies, including causes, symptoms, and prevention.

A woman making a peanut butter sandwich with friends at the beach

Corey Jenkins / Getty Images

Who’s at Risk of Peanut Allergy Symptoms and Why?

Children with an egg allergy, moderate-to-severe atopic dermatitis (eczema), and/or an immediate family member with a peanut allergy are at the highest risk for developing a peanut allergy. Those with mild-to-moderate atopic dermatitis and no existing food allergies are at moderate risk.

This is because atopic dermatitis causes cracks in the skin barrier, allowing bacteria and allergens to penetrate the skin. When cracked skin comes into contact with peanuts or other allergens, its immune cells may overreact, triggering an allergic reaction.

Some children go on to develop asthma or allergic rhinitis. The progression from atopic dermatitis to later developing food allergies, asthma, and allergic rhinitis is called the allergic march.

When Do Peanut Allergies Start?

Peanut allergies generally start in childhood. However, they can develop at any time. One study found that 1 in 6 adults with a peanut allergy experienced their first reaction in adulthood, suggesting that more adults are developing peanut allergies than previously believed.

In adults, peanut allergies are more common among:

  • Females
  • Adults with a higher household income
  • People with atopic dermatitis, asthma, and environmental allergies

Unlike milk or egg allergies, which children often grow out of, peanut allergies are usually lifelong. Only 20% of children will outgrow their peanut allergy over time.

Common Peanut Allergy Symptoms

Peanut allergy symptoms generally occur within minutes but may take up to two hours to develop. In rare cases, the reaction may be delayed as long as six hours.

Reactions vary and can range from mild to severe. A person may not always experience the same response. Even if peanuts usually cause only mild reactions, they can potentially lead to more severe symptoms in the future.

Mild Signs

Mild reactions typically only affect one part of your body and may include:

  • A few hives, a mild rash or itch
  • Itchy mouth
  • Mild nausea or abdominal discomfort
  • Sneezing or an itchy, runny nose

Compared to other food allergies, peanut allergies are more likely to result in severe allergic reactions and anaphylaxis due to accidental exposure.

Severe, Life-Threatening Reactions

Severe reactions can quickly progress to a severe, life-threatening reaction called anaphylaxis. Symptoms of anaphylaxis often involve multiple body systems at the same time, which can include:

Severe reactions should be treated immediately with an epinephrine injection, best administered with an autoinjector.

When to Seek Emergency Care

Seek emergency medical care at the first signs of anaphylaxis, even after administering epinephrine. A second anaphylactic reaction (biphasic reaction) can happen up to 12 hours after the first reaction. Although rates of death caused by anaphylaxis from peanuts are low, it is one of the most common food allergens to result in death.

What to Do for a Mild Reaction

If you are experiencing a few hives, sneezing, mild itching, or nausea after consuming peanuts, your healthcare provider may prescribe or recommend over-the-counter (OTC) antihistamines such as Benadryl (diphenhydramine) or Zyrtec (cetirizine).

Antihistamines block or reduce chemicals your body releases when you encounter an allergen. However, antihistamines will not treat a severe reaction or anaphylaxis and should never be used instead of epinephrine.

What Causes a Peanut Allergy?

Peanut allergies occur when the immune system mistakenly identifies proteins in peanuts as harmful, triggering histamine release.

The most common cause of peanut allergy symptoms is eating peanuts or foods that contain peanuts. However, exposure to peanuts can also occur in other ways, including:

  • Direct skin contact: In some cases touching peanuts can result in allergic reactions, especially if you rub your eyes after touching peanuts or a surface with the allergen on it.
  • Cross-contact: Peanut proteins can be unintentionally transferred from food containing peanuts to food not containing them during preparation. This cross-contact (also called cross-contamination) can result in a severe allergic reaction.
  • Inhalation: Peanut dust and particles containing peanut proteins that become airborne may cause an allergic reaction. Some people report chest tightness or skin rashes when being near or smelling peanut butter. However, studies have yet to confirm these effects.

How Are Peanut Allergies Diagnosed?

Diagnosing a peanut allergy can be challenging because symptoms vary from person to person. If you suspect you have a peanut allergy, it's important to contact an allergist, who will typically ask about your personal and family histories and may order a skin or blood test.

The allergist may also recommend an oral food challenge, in which you will be fed tiny amounts of peanut or peanut products under medical supervision in progressively increasing amounts.

At-Home Food Allergy Tests

Most at-home food allergy test kits measure immunoglobulin E (IgE) antibody levels in your blood to identify a potential food allergy. Experts don't recommend them as they may not provide accurate results and may be challenging to interpret. If you try an at-home allergy test, review your results with a healthcare provider to receive an official peanut allergy diagnosis.

How Can I Prevent Reactions?

The best way to prevent allergic reactions is to avoid peanuts and products containing peanuts. Peanuts and peanut products are found in many foods, including baked goods, cereals, candies, and pies.

The Food Allergen Labeling and Consumer Protection Act requires major allergens, including peanuts, to be declared at least once on food ingredient labels.

Foods not made with peanuts can still be at risk of cross-contamination during processing or preparation, which means traces of peanuts may be present in these products. Read labels carefully and avoid products that say "may contain peanuts," "made in a facility that processes nut ingredients," or something similar if you have a peanut allergy. However, these are voluntary statements that are not required by law.

When eating out, ask restaurant staff about the ingredients used to prepare meals. Avoid eating Asian and Mexican cuisine, in which peanuts are frequently used.

It's also important to be mindful when consuming foods that contain tree nuts, like walnuts, almonds, and pecans, as 30% of individuals with peanut allergies are also allergic to tree nuts.

Oral Immunotherapy for Peanut Allergies

The Food and Drug Administration (FDA) approved Palforzia, a peanut protein powder used to treat peanut allergies in children ages 4 to 17. It slowly introduces a child to peanuts, so their immune system is less likely to react if peanut products are accidentally ingested. Even with this medication, peanuts should be avoided, and epinephrine should always be available.

Summary

Peanut allergy is one of the most common food allergies. Symptoms can range from mild to life-threatening, including runny nose, hives, facial swelling, and anaphylaxis in rare cases. Most peanut allergies start in the first few years of life, but it's also possible for adults to become allergic to peanuts. If you suspect you have a peanut allergy, contact an allergist who can perform testing to confirm whether you are allergic to peanuts.

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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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Lindsey DeSoto

By Lindsey DeSoto, RD, LD
Lindsey Desoto is a registered dietitian with experience working with clients to improve their diet for health-related reasons. She enjoys staying up to date on the latest research and translating nutrition science into practical eating advice to help others live healthier lives.