The Truth About Nut Allergies

More than 170 foods have been reported to cause allergic reactions, but just nine are considered the most common in the United States. High on the list of common foods that cause allergic reactions are tree nuts. Not to be confused with peanuts, which are legumes that grow underground, tree nuts grow on trees and the most common include walnuts, almonds, hazelnuts, pecans, cashews, pistachios, macadamia nuts, pine nuts, and Brazil nuts. Collectively, these tree nuts cause allergic reactions in roughly 0.5 to 1% of the American population. This includes men, women, and children.

If you’ve ever been curious about nut allergies, this article will discuss nut allergy causes, treatments, and symptoms.

What causes nut allergy?

There is no one cause for nut allergy, but it is believed that most people develop the condition when they are young. However, it is possible to develop a nut allergy or sensitivity later in life.

When a person has a nut allergy, the body’s immune system mistakenly identifies the nut protein as a threat. Researchers at Mayo Clinic say when this happens, the immune system triggers cells to release an antibody known as immunoglobulin E (IgE) to neutralize the allergen. The next time the individual eats even the tiniest amount of nuts, IgE antibodies sense it and signal the immune system to release a chemical called histamine and other chemicals into the bloodstream. These chemicals cause allergy symptoms (a reaction). Reactions can be mild to severe and may include everything from an itchy mouth or hives to wheezing, and even anaphylaxis.

What are the different types of tree nuts?

The U.S. Food and Drug Administration (FDA) classifies the following nuts as tree nuts:


Common or Usual name Scientific name
Almond Prunus dulcis (Rosaceae)
Beech nut Fagus spp. (Fagaceae)
Brazil nut Bertholletia excelsa (Lecythidaceae)
Butternut Juglans cinerea (Juglandaceae)
Cashew Anacardium occidentale (Anacardiaceae)
Chestnut (Chinese, American, European, Seguin) Castanea spp. (Fagaceae)
Chinquapin Castanea pumila (Fagaceae)
Coconut Cocos nucifera L. (Arecaceae (alt. Palmae))
Filbert/hazelnut Corylus spp. (Betulaceae)
Ginko nut Ginkgo biloba L. (Ginkgoaceae)
Hickory nut Carya spp. (Juglandaceae)
Lichee nut Litchi chinensis Sonn. (Sapindaceae)
Macadamia nut/Bush nut Macadamia spp. (Proteaceae)
Pecan Carya illinoensis (Juglandaceae)
Pine nut/Pinon nut Pinus spp. (Pineaceae)
Pili nut Canarium ovatum Engl. in A. DC.(Burseraceae)
Pistachio Pistacia vera L. (Anacardiaceae)
Shea nut Vitellaria paradoxa C.F. Gaertn. (Sapotaceae)
Walnut ( English, Persian, Black, Japanese, California), Heartnut, Butternut Juglans spp. (Juglandaceae)
What is the most common tree nut allergy?

The tree nuts that cause the most allergic reactions in children and adults in the U.S. include walnuts, almonds, hazelnuts, pecans, cashews, pistachios, macadamia nuts, pine nuts, and Brazil nuts. Of these, walnuts, almonds, hazelnuts, pecans, cashews, and pistachios cause the most allergic reactions in adults and children. Of these, the National Institutes of Health (NIH) reports that walnut allergy is the most common tree nut allergy in the United States. In northern Europe, hazelnut allergy is prevalent.

What nuts are not tree nuts?

Despite having the word “nut” in its name, a peanut is not a tree nut. It’s a legume that grows underground. Nuts grow on trees. Nutmeg (a seed), water chestnut (a vegetable), and butternut squash (a fruit) also contain the word “nut,” but they are not tree nuts.

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

A peanut is not considered a tree nut because it doesn’t grow on trees or in shrubs. The flowers of the peanut plant grow above ground, while the actual peanut grows in pods that mature below ground. The peanut is classified as a legume, so it’s in the same family as beans, lentils, and peas.

Although peanuts and tree nuts are different, one study estimates that 30% of people with peanut allergy are also allergic to tree nuts. Further, the reason why people react to both is the same. When a person with nut allergy or peanut allergy ingests either, the body’s immune system processes the proteins contained in them as a threat. When this happens the body releases chemicals that cause physical reactions.

What are the symptoms of a nut allergy?

Nut allergy symptoms can develop within a few minutes to two hours after eating a nut or ingesting anything than contains nuts or nut proteins. In rare cases, it can take several hours for symptoms to develop. For some people living with nut allergy, reactions can be mild. In others, reactions can be severe to life-threatening.

The most common nut allergy symptoms include:

  • Abdominal pain, diarrhea, nausea or vomiting.
  • Dizziness, lightheadedness, or fainting.
  • Hives, itching, or eczema.
  • Swelling of the lips, face, tongue, and throat or other parts of the body.
  • Tingling or itching in the mouth.
  • Wheezing, nasal congestion, or trouble breathing.
  • Difficulty swallowing.

Although it’s considered rare, the most life-threatening nut allergy reaction is anaphylaxis. Symptoms of anaphylaxis include:

  • Constriction and tightening of the airways.
  • Dizziness, lightheadedness, or loss of consciousness.
  • Rapid pulse.
  • Shock with a severe drop in blood pressure.
  • Swollen throat or the sensation of a lump in your throat that makes it difficult to breathe.

Anaphylaxis requires immediate medical attention. If left untreated, anaphylaxis can cause a coma or even death.

How do you diagnose nut allergy?

There is no one test to diagnose nut allergy. To help diagnose the condition, your doctor or allergist will use a variety of methods and tools. They will likely begin by assessing your symptoms and family history, performing a physical exam, and ordering skin and blood tests. According to Kids With Food Allergies (KFA), a skin test or skin prick test (SPT) involves placing a drop of allergen onto the surface of the skin, and then pricking through it to introduce the allergen into the top layer of the skin. A blood test can measure the immune system’s response to suspected foods by measuring IgE.

Your doctor or allergist may also suggest an elimination diet, which involves eliminating suspected nuts for a week or two, then adding them back into the diet one by one. This will determine if you have a true nut allergy or a nut sensitivity.

An oral food challenge may also be performed to confirm if a tree nut does or does not cause an allergic reaction. During an oral food challenge, you will eat the suspected nut (or nuts) to determine if it is causing your symptoms. An oral food challenge is performed under the supervision of a doctor or allergist.

Is there a cure for nut allergy?

While it is estimated that 1 in 5 children may outgrow a nut allergy, the condition is usually lifelong and there is no cure. However, over-the-counter (OTC) remedies and treatments do exist. For example, if you have mild reactions to tree nuts, carrying an antihistamine can help. Offered over-the-counter, an antihistamine can be taken after exposure to tree nuts to help relieve symptoms such as hives and itching.

Diphenhydramine (Benadryl) is one of the most common antihistamines for nut allergy. For severe reactions, you might have to carry an epinephrine autoinjector (EpiPen). This device contains a single dose of medication that can be injected into the thigh. An EpiPen is commonly used for anaphylaxis.

A common medical treatment for nut allergy is oral immunotherapy treatment (OIT). Performed under the medical supervision of a board-certified allergist, OIT involves ingesting diluted doses of the allergen over a period of several hours. At home, the individual will take doses twice a day. The dose potency is gradually increased over six months to a year in hopes of building up a tolerance to the allergen.

Once the process is complete, your allergist will administer tests to make sure you have become tolerant of the allergen. The benefits of OIT include:

  • Reduces chances of allergic reactions.
  • Reduces fear.
  • Enables a healthy diet.
  • Safe treatment.
  • Suitable for all ages.

The best defense against nut allergy is to avoid exposure. However, many foods and products contain nuts, so avoiding them altogether isn’t always possible. OIT can help reduce the chance of an allergic reaction should you unknowingly ingest tree nuts or their components, which can be hidden in everything from foods to nutritional supplements.

Unexpected foods that contain tree nuts:

Tree nuts and tree nut proteins can be found in many foods and products. Some are common while others are unexpected. Some of the most common foods that contain tree nut proteins include:

  • Black walnut hull extract (flavoring).
  • Natural nut extract Nut distillates/alcoholic extracts Nut oils (e.g., walnut oil, almond oil).
  • Walnut hull extract (flavoring).     

Some of the most unexpected foods and products that contain nuts and nut proteins include:

  • Alcoholic beverages (flavorings).
  • Barbeque sauces and marinades.
  • Breakfast cereals.
  • Candy and chocolates.
  • Cold cuts, such as mortadella.
  • Cookies and crackers.
  • Energy bars.
  • Flavored coffee.
  • Ice cream and other frozen desserts.
  • Natural sponges and brushes.
  • Nutritional supplements.
  • Pink peppercorn (related to cashews).
  • Shampoos, lotions, and soaps.
How do I avoid an allergic reaction if I have a nut allergy?

Avoiding tree nuts and tree nut proteins can be challenging, but with a little detective work, you can prevent frequent reactions and live a full and rewarding life. One of the best ways to avoid an allergic reaction is to become a label reader. Avoid anything that contains tree nut or tree nut proteins. When reading food labels, look for tree nuts or any of these ingredients:

  • Artificial nuts.
  • Beechnut.
  • Black walnut hull extract (flavoring).
  • Chinquapin nut.
  • Coconut.
  • Gianduja (a chocolate-nut mixture).
  • Marzipan/almond paste.
  • Nangai nut.
  • Natural nut extract (almond, walnut).
  • Nut butters (cashew butter, almond butter).
  • Nut distillates/alcoholic extracts.
  • Nut meal.
  • Nut meat.
  • Nut milk (almond milk, cashew milk).
  • Nut oils (walnut oil, almond oil).
  • Nut paste (almond paste).
  • Nut pieces.
  • Pesto.
  • Praline.
  • Walnut hull extract (flavoring).

We understand that this next preventive measure might be tough, but it’s also best to avoid ice cream parlors, bakeries, coffee shops, and certain restaurants including Chinese, Indian, African, Thai, and Vietnamese. Tree nuts are commonly found in many ethnic foods and sauces, so even if you order a tree-nut free dish at a restaurant, there is still a high risk of your dish coming in contact with the allergen.

Frequently asked questions about nut allergy:

How many types of nut allergies are there?

Two: peanut and tree nut.

Are coconuts a tree nut allergy?

According to Johns Hopkins All Children’s Hospital, some people who are allergic to tree nuts, such as walnuts, almonds, and cashews, are also allergic to coconut. But others are not.

Are avocados a tree nut allergy?

Biologically, an avocado is a fruit, not a tree nut. So avocadoes are not a tree nut allergy.

Are almonds a tree nut allergy?

Almonds belong to the group of the nine most common tree nuts that cause allergies.

What foods should I avoid if I have tree nut allergy?

Avoid all foods that contain tree nuts, tree nut ingredients, nut butters, nut pastes, nut oils, nut milk, nut pieces, and nut flavoring. For specific foods and products to avoid, please refer to the earlier sections about unexpected foods that contain tree nuts and how to avoid an allergic reaction.

How do I eat out with a nut allergy?

It’s best to avoid most ethnic restaurants, as well as bakeries, coffee shops, and ice cream parlors. Look for restaurants that promote themselves as “nut-free” or “allergy-friendly.” According to bon appétit, chain restaurants such as Chipotle, Legal Seafoods, California Pizza Kitchen, Rainforest Cafe, and P.F. Chang’s consistently make Allergy Eats’ Top Ten list of allergy-friendly restaurants because of their strict kitchen protocols for communicating with and accommodating allergic diners. You can use Allergy Eats to search for allergy-friendly restaurants nationwide.

If you do find yourself in a restaurant that’s neither nut-free or allergy-friendly, do your best to communicate to waitstaff that you have a nut allergy, so nuts must be avoided at all costs. In most cases, the restaurant will be more than happy to accommodate you.

How can a MedicAlert ID and protection plan help protect someone living with a nut allergy?

A MedicAlert ID and protection plan for nut allergy can play an important role in managing your condition. This is especially true in an emergency. A MedicAlert ID and protection plan can be your voice if you are unable to communicate critical information about your condition to first responders, ER doctors, and hospital staff in an emergency. Our Advantage Plus protection plan is the smart choice for people living with nut allergy.

Advantage Plus provides:

• 24/7 emergency response team to relay vital information to first responders, ensuring safe and accurate care.
• Designated physician and emergency contact notification.
• Digital health profile of all allergies, medications, and auto-injectable devices, such as an EpiPen – all in one place.
• Personal document storage.
• Printable detailed profile for your medical appointments.

How do you order a MedicAlert ID for nut allergy?

The easiest way to order a MedicAlert ID for yourself or a loved one who has one or more severe allergies is to go to the MedicAlert website and select Shop All IDs.

With a variety of ID types available, including bracelets, necklaces, cards, shoe tags, and more, you will easily find something that fits your style and comfort needs. And if you or your loved one happens to be allergic to nickel or other metals used to make many medical IDs, MedicAlert also has silicone, nylon, and other non-allergenic ID options.

Your Medical ID can be engraved with any vital medical information that can help protect and save your life in an emergency. You can fill in your information securely online, submit your order, and have your MedicAlert ID engraved and delivered in just a few days.

Live life to the fullest without worry. Order your MedicAlert ID today and start enjoying the protection of our 24/7 support.

What should you engrave on a MedicAlert ID for allergies?

MedicAlert offers free custom engraving on all our medical ID products. The engraving should include any critical medical information that can help protect and save your life if you are in an accident or have another medical emergency, including:

  • Type and severity of allergies (anaphylaxis).
  • Current medications.
  • Use of an epinephrine delivery device (EpiPen), nebulizer, inhaler, etc.
  • Physician and in case of emergency (ICE) contacts.
  • Any other important medical information that can help protect and save your life in an emergency.  

Sources: Allergy Eats; American Academy of Allergy Asthma & Immunology (AAAAI); American College of Allergy, Asthma & Immunology (ACAAI); Better Health Channel-Victoria State Government; bon appétit; Food Allergies Atlanta; Food Allergy Canada; Food Allergy Research and Education (FARE); Harvard School of Public Health-The Nutrition Source; Johns Hopkins All Children’s Hospital;; Kids With Food Allergies (KFA); Mayo Clinic; National Institutes of Health (NIH)-National Library of Medicine (NLM)-National Center for Biotechnology Information (NCBI); National Peanut BoardNebraska Department of Health and Human Services (DHHS); NY Allergy & Sinus Centers; School Nutrition Association (SNA); U.S. Food & Drug Administration (FDA)-Food Allergies; U.S. Food & Drug Administration (FDA)-Tree Nuts.

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