Treenut Allergy

Tree Nut Allergy

Tree nut allergies constitute the most common allergies affecting both children and adults. Once detected, this allergy often persists for life, with only about 9% of kids naturally outgrowing it as they reach adulthood.

Although frequently mistaken for a peanut allergy (since peanuts are legumes, not nuts), a tree nut allergy is caused by proteins present in nuts like almonds, walnuts, hazelnuts, cashews, pecans, Brazil nuts, macadamia nuts, pistachios, and pine nuts. Remarkably, 25–40% of individuals allergic to peanuts also have allergies to at least one kind of tree nut.

Just like peanut allergies, a response to tree nuts occurs when food proteins and IgE antibodies bind, prompting an immune reaction that can lead to symptoms ranging from mild discomfort to severe responses.

Tree Nut Allergy Reaction Symptoms

Allergic reactions to tree nuts can last from a few minutes to several hours. The most common mild symptoms are:

• Nasal congestion or running nose
• Itching or swelling in the throat or mouth
• Throat constriction
• Shortness of breath
• Itchy eyes or skin
• Difficulty breathing or wheezing
• Abdominal discomfort or cramps
• Nausea and vomiting
• Diarrhea
• Trouble swallowing
• Headache
• Anxiety
• Hives

Severe reactions and anaphylaxis

In severe cases, a tree nut allergy can lead to anaphylaxis, making the body go into shock. Possible severe anaphylactic reaction signs include:

• Pale or bluish skin
• A fall in blood pressure
• Swelling of the throat or tongue
• Weak or rapid heartbeat
• Throat constriction
• Confusion or dizziness
• Fainting or unconsciousness

Anaphylaxis is considered a medical emergency that requires immediate treatment with epinephrine. Individuals with a tree nut allergy need to carry two epinephrine auto-injectors at all times for prompt treatment in the event of accidental exposure.

Common Triggers

• Tree nuts: Includes walnuts, almonds, hazelnuts, cashews, pecans, pistachios, macadamia nuts, Brazil nuts, and pine nuts.
• Tree nut products: Such as nut oils, nut butter, and other food items containing tree nut derivatives.

Risk Factors

Certain groups are at a higher risk of developing a tree nut allergy:

• Individuals with peanut allergies: About 30–40% of people with a peanut allergy may also develop a tree nut allergy due to the presence of similar proteins in both. However, having a tree nut allergy does not always mean an allergy to peanuts, though it is common to be allergic to both.
• Infants with eczema or egg allergies: Babies with eczema or an egg allergy are at an increased risk of developing additional food allergies, including tree nut allergies.

Testing and Diagnosis

Tree nut allergy diagnosis involves the following methods:

• Skin prick test: This safe, low-risk test involves lightly pricking the skin with a small amount of the suspected allergen. A clinician will then monitor for skin reactions, such as hives or bumps, with minor itchiness being the prevalent side effect.
• Blood test: This measures the levels of specific IgE antibodies produced by the immune system in response to nut proteins. The blood sample is taken to a lab for more evaluation, and results typically take a few days. This method is safe for all age groups, including infants, children, and adults.
• Component test: This specialized blood test evaluates whether an individual can tolerate specific components of nut proteins. It offers greater precision in identifying the risk of severe reactions, such as anaphylaxis, and helps pinpoint less harmful aspects of the allergen. Component testing is particularly reliable for walnuts, hazelnuts, cashews, and Brazil nuts.
• Oral food challenge: Often used as a last step, this test determines whether one has outgrown a food allergy or clarifies inconclusive results from other tests. Conducted under strict medical supervision, the patient consumes very small, gradually increasing amounts of a specific tree nut over a 3–4 hour period. This test is only performed after a thorough review of medical history and when it is determined to be safe and successful.

Treatment Options

The most effective treatment option for individuals of all ages with tree nut allergies is oral immunotherapy (OIT). This approach reduces the risk of reactions caused by accidental exposure to allergens, allowing patients to feel more confident in maintaining a balanced diet.

OIT involves gradually introducing small doses of allergens to the patient over time. This process helps desensitize the body and retrains the immune system, reducing the severity of allergic reactions. In some cases, OIT can be combined with Xolair, an anti-IgE monoclonal antibody, which may further suppress allergic responses.

At times, treating an allergy to one type of nut can also protect against reactions to another. For instance, OIT for cashew allergies may protect against pistachio reactions, while OIT for walnut allergies can reduce sensitivity to pecans. New studies indicate that walnut allergy treatment might also offer cross-protection for hazelnuts.

OIT significantly improves the quality of life for many patients. Studies show that when performed by experienced clinicians, OIT is about 85% effective.

Living with a Tree Nut Allergy

Completely avoiding tree nuts and foods containing tree nuts is essential for managing the condition. Tree nuts are commonly used in various cuisines, such as Asian, Indian, Thai, Chinese, and Vietnamese dishes, and are often hidden in many processed and prepared foods.

Common foods containing tree nuts include:

• Nut butter, including almond butter and cashew butter
• Nut milk. Almond milk, hazelnut milk, cashew milk
• Pastries, biscuits, and cakes made with nuts like carrot cake, chocolate brownies, Bakewell tart, macaroons, and amaretto biscuits
• Hazelnut spreads such as Nutella
• Confectionery and chocolates (such as Ferrero Rocher, nougat, Toblerone, Topic, Snickers, and Picnic) and assorted sweet selections (Roses, Quality Street, Celebrations)
• Ice cream such as nut-flavored varieties like pistachio or those with nut toppings
• Gluten-free foods made with almond meal
• Marzipan
• Food Flavoring such as almond extract
• Pesto, which might contain tree nuts and pine nuts
• Breakfast cereals (muesli, honey nut cornflakes)
• Bread and crackers, including specialty varieties like walnut bread or those topped with nuts
• Cereal bars
• Vegetarian foods such as nut roasts and veggie burgers
• Mixed nuts and raisins
• Salads topped with nuts or made with nut oils

Takeaways

Managing a tree nut allergy requires vigilance and preparation, but with the right knowledge and tools, it’s possible to live safely and confidently. Understanding potential triggers and being prepared for emergencies are essential steps in reducing risks. Also, by staying informed and proactive, individuals with tree nut allergies can lead healthy and fulfilling lives while minimizing the chances of allergic reactions.