Tree Nut

Symptoms

An allergy to tree nuts is one of the most common food allergies. Along with peanuts and shellfish, it is also one of the food allergens most frequently linked to anaphylaxis, a potentially life-threatening reaction that impairs breathing and can send the body into shock.

Symptoms of a tree nut allergy include:

• Abdominal pain, cramps, nausea and vomiting
• Diarrhea
• Difficulty swallowing
• Itching of the mouth, throat, eyes, skin or any other area
• Nasal congestion or a runny nose
• Nausea
• Shortness of breath
• Anaphylaxis (less common)

If you experience any of these symptoms after consuming tree nuts, see an allergist.

Diagnosis

Because a tree nut allergy can cause a life-threatening reaction, an accurate diagnosis is essential. Your allergist will start by taking a medical history, asking about any previous allergic reactions and about any family history of allergies. Skin-prick tests and/or blood tests may be used to determine the presence of allergen-specific immunoglobulin E, an antibody that binds to allergens and triggers the release of chemicals that cause symptoms.

If those tests are inconclusive, your allergist may order an oral food challenge. In this test, a patient is fed tiny amounts of the suspected allergy-causing food in increasing doses over a period of time, under strict supervision in an allergist’s office or a food challenge center. Emergency medication and emergency equipment must be on hand during this procedure.

Management and Treatment

As with most food allergies, the best way to avoid triggering an allergic reaction is to avoid eating the offending item.

People who are diagnosed with an allergy to a specific tree nut may be able to tolerate other tree nuts, but allergists usually advise these patients to avoid all nuts. Tree nuts are often used as garnishes in salads, as an ingredient in Asian dishes, and as an ice cream topping. They may also be found in baking mixes, breading, sauces, desserts and baked goods.

Tree nuts are among the eight most common food allergens affecting adults and children, and are specifically mentioned in the Food Allergen Labeling and Consumer Protection Act (FALCPA) of 2004. This means that the presence of these items must be highlighted, in clear language, on ingredient lists. Some companies may voluntarily include information that their food products that don’t contain nuts were manufactured in a facility that also processes nuts, though such a statement is not required by law. It is important for people with tree nut allergies to read labels carefully.

Some alcoholic beverages may contain nuts or nut flavoring added in the distillation process. Most alcoholic beverages aren’t covered by the FALCPA requirements; if “natural flavors” or “botanicals” are cited as an ingredient, you may need to call the manufacturer to determine whether that indicates the presence of nuts or nut flavoring.

Tree nut oils, which may contain nut protein, can be found in lotions, hair care products and soaps; those allergic to tree nuts should avoid using these products.

Fortunately, allergists are specially trained to help identify these hidden sources of tree nut allergens.

Tree nuts and peanuts

There’s often confusion between peanuts and tree nuts. Peanuts are legumes, not nuts; still, between 25 and 40 percent of individuals who are allergic to peanuts also react to at least one tree nut, according to studies.

Allergists generally advise people who are allergic to tree nuts also to avoid peanuts because of the risk of cross-contact and cross-contamination between tree nuts and peanuts in food processing facilities. If you or your child is allergic to either peanuts or tree nuts, ask your allergist whether you should avoid both products.

The prevalence of these allergies in children appears to be growing. Approximately 2.2% of children/adolescents in the U.S. have peanut allergies. Annual incidence has increased since 2001, where the current annual incidence in one year olds is nearly 5%.

Allergies to tree nuts and peanuts are among the most common causes of anaphylaxis in the United States. An allergist will advise patients with these allergies to carry an auto-injector containing epinephrine (adrenaline), which is the only treatment for anaphylactic shock, and will teach the patient how to use it. If a child has the allergy, teachers and caregivers should be made aware of his or her condition as well.

People with tree nut allergies often wonder if they must also avoid coconut and nutmeg.

Coconut is not a botanical nut; it is classified as a fruit, even though the Food and Drug Administration recognizes coconut as a tree nut. While allergic reactions to coconut have been documented, most people who are allergic to tree nuts can safely eat coconut. If you are allergic to tree nuts, talk to your allergist before adding coconut to your diet.

Nutmeg is a spice that is derived from seeds, not nuts. It may be safely consumed by people with a tree nut allergy.

Use the Find an Allergist tool to find expert care for your tree nut allergy.

This page was reviewed for accuracy June 28, 2023.