Variety of foods, including nuts, on a table

3 causes of peanut allergy

Medically reviewed on August 1, 2022 by Jordan Stachel, MS, RDN, CPT. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Table of contents

Having a food allergy doesn’t always mean you have to skip your favorite dishes and desserts. Instead, it means you just need to take a little extra care when it comes to ingredients and find substitutions that are equally delicious but don’t give you an allergic reaction. For many people, peanuts are that food.

While peanut allergies are fairly common, you might still wonder why you have one in the first place. [1] So, what causes peanut allergy?

While there isn’t a completely clear answer, we can shed light on some potential causes from genetic roots to food production processes. By learning about the causes, you’ll be able to better understand your peanut allergies, their symptoms, and how to prevent reactions.

Peanut allergies 101

An allergic reaction to peanuts happens when an individual who is allergic to peanuts comes into contact with them. This could be through eating peanuts, inhaling peanuts, or even touching them.

Peanut allergies work similarly to other allergic reactions. The impacted individual eats or otherwise comes into contact with peanuts. This starts a chain reaction in which: [2]

  • Peanut protein triggers the immune system’s response
  • The immune system produces antibodies to combat the peanut allergen
  • Your immune system releases histamine along with the antibodies
  • Your body experiences an allergic reaction and symptoms as a result

The severity of your allergic reaction depends on the severity of your allergy. Some people might only experience mild symptoms after eating peanuts, while others may go into anaphylactic shock and require emergency medical care.

Peanut allergy causes

More research is needed to fully understand what causes peanut allergy. However, there are several potential reasons why some people have an allergy to peanuts.

These include:

  • Genetics
  • Exposure
  • Cross-contamination

Let’s look at each of these potential causes in more detail.

Genetic factors and peanut allergies

One potential cause of peanut allergies could be your genes. But that doesn’t necessarily mean other family members have to have peanut allergies for you to have them.

Although studies are limited, there is some suggestion that a specific genetic mutation could set the table for the development of a peanut allergy. [3] Not everyone with the mutation develops an allergy to peanuts, though. If you have this mutation, it just makes it more likely that you could.

Frequent exposure to peanuts

Your level of exposure to peanuts can also play a role in allergy development. Some researchers propose that there are more people with peanut allergies these days simply because we eat more peanuts and products containing them now than ever before. [4]

For instance, you can find peanuts in:

  • Baked goods
  • Candy
  • Cereal
  • Sauces
  • Soups
  • Bread
  • Energy bars

Even products that don’t contain peanuts might contain peanut oil. The widespread use of peanuts as an ingredient also makes it more likely that someone allergic to peanuts may come into contact with them.

Food production methods

Even when you don’t consume foods that contain peanuts directly, you might still risk an allergic reaction because of cross-contamination.

Much of the food we eat is made or processed in vast facilities that produce a wide variety of foods. These facilities might share equipment between different types of food, but even if they don’t, it’s possible for allergens to reach other foods. The likelihood of cross-contamination is high in these facilities, and it can cause problems for peanut allergy sufferers.

Is a peanut allergy the same as a tree nut allergy?

Peanuts belong to the legume family. Therefore, someone who is allergic to peanuts may or may not also be allergic to tree nuts. Peanuts and tree nuts share some common proteins, which is why you can be allergic to one or both.

Common tree nuts include: [5]

  • Almonds
  • Hazelnuts
  • Walnuts
  • Brazil nuts
  • Macadamia nuts
  • Pecans
  • Pistachios
  • Cashews

Still, some people who react to peanuts can eat other nuts without any issues. You would have to test for a tree nut allergy separately from peanuts to determine if you were allergic to both.

What are the symptoms of a peanut allergy?

How do I know if I’m having an allergic reaction to peanuts? These often appear for the first time in childhood. Some people will outgrow their allergy, but many will need to avoid peanuts for their entire lifespan.

When someone has an allergic reaction to peanuts, they may experience the following symptoms: [5]

  • Wheezing and trouble breathing comfortably
  • Stomach pain, vomiting, and diarrhea
  • Watery, itchy, red, or swollen eyes
  • Sore throat and tightness in the throat
  • Hives or skin rash
  • Dizziness or fainting

If you have a severe peanut allergy, a more serious reaction called anaphylaxis can occur. Anaphylaxis is an extreme and life-threatening allergic reaction characterized by a rapid release of chemicals from your immune system.

When these chemicals flood your body, you can go into a state of shock. Your blood pressure drops significantly, your heart rate increases or decreases, and you may have extreme difficulty breathing.

In these life-threatening situations, you should always seek immediate emergency medical attention.

How are peanut allergies diagnosed?

Diagnosing food allergies can be tricky. Ingredients in certain products aren’t always clear or properly disclosed. Furthermore, different people might experience different symptoms in response to an allergen.

This being said, if you think you or your child is allergic to peanuts, the allergy can be diagnosed using: [6]

  • A skin test – In a skin test, a tiny amount of the allergen (in this case, peanut allergen) is placed on your skin. Your skin is then lightly pricked with a small needle. If you’re allergic to peanuts, your skin will likely develop a red bump at the site of the skin prick.
  • A blood test – A blood test can also be used to diagnose a peanut allergy. A small sample of your blood will be drawn and analyzed. The analyst will look for certain antibodies in your blood known as immunoglobulin E (IgE). If these antibodies are present, you may have an allergy.
  • Supervised food challenge – Finally, you may also need to complete a supervised food challenge. A food challenge is where you are asked to ingest a small amount of peanuts while being supervised by a medical professional. During this challenge, your healthcare provider can observe you for potential reactions and keep a close watch for serious reactions so that they can respond quickly to keep you safe.

You might also be asked to keep a food diary, track allergic symptoms, and eliminate certain foods from your diet. Each of these diagnostic methods can help you narrow down the potential cause or causes of your discomfort and set you on the path to feeling better.

How are peanut allergies treated?

There is no real peanut allergy treatment, other than avoiding exposure.

  • Oral Immunotherapy – Some studies have been conducted on oral immunotherapy with varying results. [4] In oral immunotherapy, children are given small amounts of peanuts while under supervision. It’s believed that small exposures over time may help desensitize those who have an allergy, eventually leading to a better tolerance of peanuts. This type of treatment is a little controversial, and not without risks. Children who are allergic to peanuts can still experience anaphylaxis, even when under observation.
  • EpiPen – The other treatment option for those experiencing an allergic reaction is an epinephrine injection. You may have heard of the EpiPen, which is a small device allergy sufferers can carry with them. If exposed to an allergen that triggers a serious reaction, the individual can use the EpiPen to deliver a potentially life-saving dose of epinephrine to their body. EpiPens can be expensive, but can also make a difference in life-threatening situations.

How can you prevent allergic reactions to peanuts?

Allergic reactions can sometimes become severe in only a few minutes. Even in milder cases, however, they can cause you discomfort that you’d probably rather avoid. So, how can you keep your peanut allergy in check?

The easiest way to prevent allergic reactions to peanuts is to simply avoid consuming peanuts. This is the safest and most effective way to avoid an unwanted and potentially dangerous allergic reaction.

As you aim to keep your diet peanut-free, you’ll also want to steer clear of any other peanut product or items that contain traces of peanuts. Because they’re a common allergen, peanuts are usually listed on nutrition labels when foods contain them. But you should also be aware of foods you may not expect to contain peanuts, such as: [5]

  • Candy, especially homemade or from small businesses with fewer regulations
  • Cookies, cakes, and other baked treats
  • Ice cream from ice cream shops where nuts are present
  • Sauces, specifically in Asian and African cuisine

Manufacturers are required to list the potential for cross-contamination on their labels, so always make sure you scan the packaging carefully before purchasing a product that may have been produced in a facility with peanuts.

If you have a child suffering from a peanut allergy, you should be sure to communicate with their school, camps, sports teams, and any other groups where they may come into contact with foods that could contain peanuts.

Learn more about food allergies with Everlywell

Knowing the potential causes of peanut allergies is an important part of learning to manage them. Ultimately, the best way to prevent a serious allergic reaction to peanuts is to avoid contact with them, especially if you have a severe reaction to the allergy.

However, if you have a milder allergy to peanuts, diagnosing your symptoms requires the right tools. If you want to learn more about any potential food allergies you might have, we can help.

The Everlywell Food Allergy Test is a safe, convenient, at-home test that will help you better understand your body’s reactivity to common food allergens, including peanuts.

Once you receive your test results, you can work with your healthcare professional to determine the best way to manage your allergies.

Peanut allergy symptoms explained

How to test for soy allergy at home

Shellfish allergy symptoms and signs


  1. Food Allergy: Epidemiology and Natural History. PubMed. URL. Accessed August 1, 2022.
  2. What is Peanut Allergy? Food Allergy Research and Education. URL. Accessed August 1, 2022.
  3. Genome-wide Association Study Identifies Peanut Allergy Specific Loci. Nature. URL. Accessed August 1, 2022.
  4. Peanut Allergy: New Advances and Ongoing Controversies. American Academy of Pediatrics. URL. Accessed August 1, 2022.
  5. Nut and Peanut Allergy. URL. Accessed August 1, 2022.
  6. Peanut. American College of Allergy, Asthma, and Immunology. URL. Accessed August 1, 2022.
Everlywell makes lab testing easy and convenient with at-home collection and digital results in days. Learn More