Tree Nut Allergies
Evidence-based information about symptoms, diagnosis, and management of tree nut allergies
What are Tree Nut Allergies?
Tree nut allergies are among the most common food allergies and can cause severe, potentially life-threatening allergic reactions. Unlike peanut allergies (peanuts are legumes), tree nut allergies involve nuts that grow on trees, such as almonds, walnuts, cashews, and hazelnuts.
Tree nut allergies typically develop in childhood, but they can appear at any age. Most people with a tree nut allergy are allergic to more than one type of tree nut. Additionally, these allergies tend to be lifelong, with only about 9% of children outgrowing them.
Important Note
If you suspect you have a tree nut allergy, consult with an allergist for proper diagnosis before making dietary changes.
Common Tree Nuts That Cause Allergies
Almonds
Used in many foods, including baked goods, cereals, and almond milk.
Walnuts
Common in baked goods, salads, and as a standalone snack.
Cashews
Found in many Asian dishes, trail mixes, and as cashew butter.
Hazelnuts
Used in chocolate spreads, coffee flavorings, and baked goods.
Pistachios
Common in desserts, salads, and as a snack.
Brazil Nuts
Found in mixed nuts and some health foods.
Other tree nuts that can cause allergic reactions include pecans, pine nuts, macadamia nuts, and chestnuts. If you're allergic to one type of tree nut, your allergist may recommend avoiding all tree nuts due to the risk of cross-contamination and cross-reactivity.
Symptoms of Tree Nut Allergies
Allergic reactions to tree nuts can range from mild to severe and can affect various body systems. Symptoms typically appear within minutes to two hours after consuming tree nuts or foods containing tree nuts.
Common Symptoms
- Skin Reactions
- Hives, itching, redness, swelling, eczema flare-ups
- Digestive Issues
- Abdominal pain, nausea, vomiting, diarrhea, difficulty swallowing
- Respiratory Symptoms
- Runny or stuffy nose, sneezing, coughing, wheezing, shortness of breath
- Severe Reactions
- Anaphylaxis: rapid pulse, drop in blood pressure, constriction of airways, dizziness, loss of consciousness
Emergency Warning
Anaphylaxis is a medical emergency that requires immediate treatment with epinephrine (adrenaline) and a trip to the emergency room. If you or someone you're with is experiencing signs of anaphylaxis, use an epinephrine auto-injector if available and call emergency services immediately.
Diagnosis and Testing
If you suspect you have a tree nut allergy, it's important to see an allergist for proper diagnosis. Self-diagnosis can lead to unnecessary dietary restrictions or failure to identify a potentially serious allergy.
Diagnostic Methods
Medical History
Your allergist will ask detailed questions about your symptoms, when they occur, and your dietary habits.
Skin Prick Test
A small amount of tree nut protein is placed on your skin, and the skin is pricked to allow the substance to enter. If you're allergic, you'll develop a raised bump (wheal) at the test site.
Blood Test
Measures the amount of tree nut-specific IgE antibodies in your blood. Higher levels can indicate an allergic sensitivity.
Oral Food Challenge
Under medical supervision, you consume small amounts of tree nuts to see if a reaction occurs. This is typically done when other tests are inconclusive or to confirm if you've outgrown an allergy.
Your allergist will interpret the results of these tests in the context of your medical history to make an accurate diagnosis.
Managing Tree Nut Allergies
Currently, there is no cure for tree nut allergies. Management involves strict avoidance of tree nuts and being prepared for accidental exposure.
Avoidance Strategies
- Read food labels carefully. Look for statements like "Contains nuts" or "May contain traces of nuts."
- Be cautious with bakery items, which often have cross-contamination risks.
- Ask about ingredients when dining out. Inform servers and kitchen staff about your allergy.
- Be aware of hidden sources of tree nuts, such as sauces, dressings, and desserts.
- Consider potential cross-contamination in manufacturing facilities.
Emergency Preparedness
- Carry an epinephrine auto-injector (such as EpiPen® or Auvi-Q®) at all times if prescribed.
- Wear a medical alert bracelet or necklace indicating your allergy.
- Create an emergency action plan with your healthcare provider.
- Educate family members, friends, and colleagues about your allergy and how to help in an emergency.
Emerging Treatments
Research into treatments for food allergies, including tree nut allergies, is ongoing. Some promising approaches include:
- Oral Immunotherapy (OIT): Gradually introducing increasing amounts of the allergen under medical supervision to build tolerance.
- Epicutaneous Immunotherapy (EPIT): Delivering small amounts of the allergen through a patch on the skin.
- Biologics: Medications that target specific pathways in the allergic response.
These treatments are still being studied and are not yet widely available. Consult with your allergist about whether any of these approaches might be appropriate for you.