What causes allergy to tree nuts

What causes allergy to tree nuts

Some tree nuts are less commonly associated with allergy, often because they are not commonly or widely consumed within a population.

Pine Nuts

Pine nuts are a common food in southern Europe, but less common in other parts of the world. They are actually a seed, not a nut, but allergy to pine nuts is possible.

Brazil Nuts

Brazil nut allergies are not common, which may be due to their lack of popularity in the U.S. Brazil nut allergies may increase in the future since genetically modified soybeans own proteins similar to those found in Brazil nut allergen.

If you are allergic to Brazil nuts, you may also be allergic to walnuts.

Macadamia Nuts

Macadamia nuts are common in Hawaii and the tropics. There is some cross-reactivity between the allergens in macadamia nuts and hazelnuts.


Coconut allergies are rare ​and coconuts are only distantly related to other tree nuts. However, some research shows a similarity between coconut allergens and those in almonds and macadamia nuts.

Can You Eat Seeds If You Own a Nut Allergy?

Peanuts are diverse from tree nuts in that they are actually a legume.

However, 30% of people with a peanut allergy will also be allergic to at least one type of tree nut.

Generally speaking, the popularity of a tree nut translates to the incidence of allergy to that nut within a population.

Hazelnuts may cause oral allergy syndrome in people with a birch pollen allergy. Symptoms (including itching, swelling, and burning in the mouth and throat) develop within a few minutes and tend to resolve within 30 minutes to an hour.

Tree nuts are a common food allergy: in the United States, about 0.5% of the population—or about one in every 200 people—is allergic to tree nuts. Tree nuts frequently cause strong allergic reactions and may cause anaphylaxis, which is a potentially life-threatening allergic reaction.

It's possible to be allergic to just one type of tree nut, but numerous people are allergic to multiple diverse types of tree nuts.

In addition, it's common for food manufacturers to process diverse types of tree nuts on the same equipment, raising risks for people who are allergic.

What causes allergy to tree nuts

Therefore, if you own a tree nut allergy, your doctor may warn you to avoid most or every tree nuts.

Allergy to Both Tree Nuts and Peanuts

Peanuts are legumes and are biologically unrelated to tree nuts. Tree nut allergy and peanut allergy are two diverse types of allergies.

What causes allergy to tree nuts

Still, while people allergic to tree nuts are not necessarily allergic to peanuts, it's also possible be allergic to both.

You should be aware that tree nuts and peanuts are often found together in processed foods and nut mixtures. If you are diagnosed with a tree nut allergy, your allergist will advise you whether to avoid peanuts, as well.

Less Common Allergies

Other tree nuts may cause allergic symptoms, but sometimes they aren't "true" allergies.

What causes allergy to tree nuts

Oral allergy syndrome (OAS) occurs when a certain food allergen is similar to an allergen found in tree or grass pollen. As such, they echo the true allergy but tend to be less severe.


If you own a latex allergy or an avocado allergy, you may also own a chestnut allergy given the similarity between the allergens found in latex and these foods. Mugwort pollen, apples, and peaches may give you a reaction as well if you are sensitive to chestnuts.


Pecans are a common food in the southern United States, but less common elsewhere in the world.

Approximately one in 20 adults in the U.S. will own a reaction to pecans. If you own a pecan allergy, you may own a walnut allergy as well, given how similar allergens in the two nuts are.


Allergy to hazelnut is more common in Europe than in the United States.

What causes allergy to tree nuts

Hazelnut pollen is a common cause of seasonal hay fever. If you own a hazelnut pollen allergy, you are also at risk for a food allergy to the tree nut itself.

If you own a birch pollen allergy, you may experience oral allergy symptoms with eating hazelnuts. If you own a hazelnut allergy, you may also be allergic to coconut, cashews, peanuts, and soybeans, given the similarity between the allergens in these foods.

Common Allergies

The risk of allergy to tree nuts varies by the type. Though you can ultimately be allergic to any type of tree nut, there are four that are known to trigger symptoms more than others.


Almonds are the most favorite tree nut consumed in the United States and the third most common tree nut allergy. Almonds are commonly used when processing food and are ingredients in breakfast cereals, granola bars, and baked goods.

Having an almond allergy may predispose you to other tree nut allergies, especially pistachio nuts.


Pistachios commonly cause food allergy symptoms and are cross-reactive to cashews and mangoes. Hay fever to the pollen from the Parietaria weed found in Europe appears to predispose to pistachio allergy.


Cashews are the second most common allergy-causing tree nuts. The oil found in the nutshell of the cashew is known to cause contact dermatitis and is related to the oils found in the leaves of poison oak and in the skin of mangoes.

Cashew allergens are similar to those in pistachios, hazelnuts, walnuts, peanuts, sesame, and buckwheat. If you own a cashew allergy, you may also experience allergic reactions to these other foods.


Walnuts, especially English walnuts, are the most common type of tree nut allergy. If you are allergic to walnut pollen, you may experience symptoms of allergic rhinitis.

What causes allergy to tree nuts

Pecans and walnuts are closely related, so some people who are allergic to one are also allergic to the other.

Symptoms Associated With Tree Nut Allergy

Symptoms associated with a tree nut allergy include:

  1. conjunctivitis
  2. oral allergy syndrome
  3. tingling of the lips
  4. diarrhea
  5. vomiting
  6. contact dermatitis
  7. asthma (in asthmatics)
  8. urticaria (hives)
  9. angioedema
  10. abdominal pain
  11. throat tightening
  12. itching of the mouth, ears, and eyes
  13. anaphylaxis

People with tree nut allergy should carry a source of epinephrine at every times in case they own a dangerous allergic reaction.

Types of Tree Nuts

The most common tree nuts include macadamia nuts, brazil nuts, cashews, almonds, walnuts, pecans, pistachios, chestnuts, hazelnuts (filberts), and pine nuts (pignoli or pinon).

Less common tree nuts include beechnuts, butternuts, chinquapins, gingko, hickory nuts, lychee nuts, pili nuts, and shea nuts.

Children who are allergic to multiple types of tree nuts (more than one or two) are less likely to outgrow their allergy than children who are allergic to just one type of tree nut.

Allergies to More than One Nut

People can be allergic to one type of tree nut, to some tree nuts, or to numerous tree nuts but not to other types of tree nuts.

That's because some tree nuts contain similar proteins—for example, almonds and hazelnuts contain similar proteins, as do walnuts and pecans, and pistachios and cashews. Because of these protein similarities, it is common for an individual to own an allergy to both nuts. For instance, if you are allergic to cashew, you own a greater risk of being allergic to pistachios, as well.

However, most people with tree nut allergy are not allergic to every tree nuts.

What causes allergy to tree nuts

The decision to avoid every tree nuts when there is an allergy to one or more tree nuts is a personal one and one you should discuss with your doctor. In food production, the risk of cross-contact with multiple tree nuts is higher, which has led numerous health professionals to recommend avoidance of every tree nuts.

How to Avoid Cross-Contact with Tree Nut and Other Food Allergies


What causes allergy to tree nuts