Tree Nut Allergy

Tree nut allergies are when your body has an allergic reaction when you eat tree nuts. This reaction could include hives, vomiting or swelling. Some reactions can be life-threatening.

Nut allergies happen when your immune system makes a mistake. It thinks the nut is something that could harm you, so it tries to get rid of it. This can be dangerous because it can cause swelling in multiple parts of your body (anaphylaxis). This can lead to dangerous airway swelling or a severe drop in blood pressure. Call 911 (or your local emergency service number) or get to an emergency room immediately if you have face, mouth or throat swelling, difficulty breathing or swallowing, or feel faint.

Types of tree nut allergies

The most common causes of tree nut allergies include:

• Almonds
• Brazil nuts
• Cashews
• Hazelnuts (filberts)
• Heartnuts (Japanese walnuts)
• Pecans
• Pistachios
• Walnuts (including black, California, English and Persian walnuts)

But you can be allergic to any tree nut, including beechnuts, chestnuts, hickory nuts and others. Many people who have tree nut allergies are allergic to more than one type of nut.

It’s also important to note that peanuts are legumes, not tree nuts. But some people are allergic to peanuts in addition to certain tree nuts.

What are the symptoms of tree nut allergies?

Symptoms of tree nut allergies can include anything from mild hives to severe swelling. They start within a few minutes to two hours of eating nuts. Symptoms include:

• Skin reactions, like hives, rash, itching or flushing
• Digestive issues like vomiting, diarrhea or belly pain
• Swelling of your face, lips, mouth or tongue
• Itchy mouth and throat
• Hoarse voice
• Difficulty swallowing
• Wheezing
• Shortness of breath or difficulty breathing
• Lightheadedness or loss of consciousness
• Runny nose or sneezing

Touching tree nuts might cause a rash, but shouldn’t lead to a severe reaction. Nut allergies can be severe, even if you’ve only had a mild reaction in the past. Call 911 (or your local emergency service number) or go to the ER at the first sign of severe symptoms.

In addition to the symptoms above, if a baby or young child is having a reaction to tree nuts, they might have a hoarse cry, noisy breathing and/or hiccups. You might also notice they’re:

• Rubbing their eyes
• Scratching at their ears
• Pulling on their tongue
• Arching their back

What causes tree nut allergies?

Tree nut allergies happen when your immune system mistakenly thinks nuts are harmful. When you eat nuts you’re allergic to — or something that contains them — your body tries to protect you. It tries to flush the allergen out of your system by widening your blood vessels and making them leak fluid. This causes swelling, which can lead to life-threatening symptoms.

Who’s at risk?

Anyone can have tree nut allergies. But you might be at higher risk if you have:

• Other food allergies
• Allergies to pollen, pets or substances other than food
• Eczema or asthma
• A biological parent who has food allergies or other allergies, asthma or eczema

What are the complications of tree nut allergies?

The most serious complication of tree nut allergies is anaphylaxis, a life-threatening allergic reaction. It can cause uncontrolled vomiting, difficulty breathing and a severe drop in blood pressure (anaphylactic shock). Severe anaphylaxis can be fatal.

How doctors diagnose tree nut allergies

Healthcare providers diagnose nut allergies by talking to you about your symptoms and performing allergy testing. Your provider may ask you:

• What symptoms you experienced
• What you ate and how much of it you ate
• When the symptoms started
• What you did to relieve the symptoms
• How long the symptoms lasted
• Whether you have other known allergies (to food, pollen, dust, pets, etc.)
• Whether you have eczema or asthma
• Whether anyone else in your family has allergies, asthma or eczema

Testing

Testing for tree allergies might include:

• Allergy skin test: A provider pricks your skin with tiny amounts of allergens, like different kinds of nuts. They check to see if you develop a reaction and measure the reaction.
• Allergy blood test: A provider tests your blood for IgE antibodies to suspected allergens. High amounts of antibodies to a type of nut likely means you’re allergic to it.
• Food challenge test: At a doctor’s office, you’ll eat small, increasing amounts of nuts that you might be allergic to. A provider will supervise you to see if you have a reaction.

How are tree nut allergies treated?

The best way to manage tree nut allergies is to avoid the nuts you’re allergic to and any food that contains them. But there are a few treatment options that might reduce your risk of having a reaction if you’re accidentally exposed to your allergen. These include:

• Omalizumab (Xolair®) injections: These can reduce your risk of having a reaction if you’re accidentally exposed to tree nuts. You still need to avoid foods you’re allergic to.
• Oral immunotherapy (OIT): Under the supervision of a provider, you eat small amounts of tree nuts. The amount increases slowly over time. This helps build a tolerance to the allergen.
• Sublingual immunotherapy (SLIT): Like OIT, SLIT helps build a tolerance to your allergen. Your provider gives you small amounts of your allergen in a liquid under your tongue, increasing the amount slowly over time.

Emergency medications

If you have an allergic reaction, your provider might give you, or recommend you take:

• Epinephrine: Your provider will recommend you carry an epinephrine auto-injector (EpiPen® or Auvi-Q®) to use at the first signs of a severe allergic reaction.
• Antihistamines: Antihistamines can help stop or slow down an allergic reaction. But providers don’t prescribe them to prevent reactions from food allergies.

When should I see my healthcare provider?

If you think you or your child has a tree nut allergy, talk to a healthcare provider. Avoid nuts and nut-containing products until you do. They can refer you to a specialist and guide you on next steps.

When should I go to the ER?

Go to the ER or call 911 (or your local emergency service number) if you experience:

• Swelling of your face, lips, tongue or throat
• Difficulty breathing
• Chest tightness
• Hives all over your body
• Tingling hands, feet or lips
• Feeling weak, dizzy or faint
• Feeling of impending doom

What can I expect if I have a tree nut allergy?

Most people can manage tree nut allergies with avoidance and new treatment options. An allergist can talk to you about available treatments and what to do if you have a reaction. If you’re doing OIT or SLIT, your provider may occasionally test you to see if your IgE antibody levels are improving.

Allergic reactions are unpredictable and may become more severe with each additional exposure. There’s no way test for how severe an allergic reaction might be. So, even if you’ve only had minor reactions in the past, you still need to be cautious about accidentally eating nuts you’re allergic to.

What foods should you avoid?

Other than the nuts themselves, some foods that can contain tree nuts include:

• Artificial nuts
• Caponata
• Chocolate candy
• Hazelnut spread (like Nutella®)
• Marzipan
• Nougat
• Nut butters, oils, pastes and extracts
• Pesto
• Praline

Other foods that can contain nuts that you might not expect include crackers, cereals and barbecue sauce.

Ways to avoid tree nut exposure

If you or your child has a tree nut allergy, you’ll have to develop habits that help you avoid accidental exposure. Some ways you can reduce your risk of exposure include:

• Reading labels on packaged foods: In the U.S., the label must state if a product contains or could’ve come in contact with tree nuts.
• Being cautious at restaurants: Ask about whether the food contains or has come in contact with nuts. Restaurants often can’t make any guarantees. They don’t have to note allergens in their foods.
• Talking to your child about how to manage allergies: This includes not sharing food if they don’t know if it’s safe to eat. Start having these conversations at an early age.
• Talking to others about your child’s allergy: Let anyone who’s around your child know what foods are safe and unsafe for them to eat. Talk to your child’s school or daycare about plans they have in place to avoid accidental exposure. Some classrooms are nut-free or nut-sensitive.
• Asking your healthcare provider: Understand what you or your child can and can’t eat. Carefully follow all directions if you’re doing OIT, SLIT or other treatment plans.

Prepare for accidental exposure

To be prepared in case of an allergic reaction:

• Always carry an epinephrine auto-injector with you, and ask your provider to show you exactly how to use it
• Make sure your child’s school or daycare has an allergy action plan (Food Allergy & Anaphylaxis Emergency Care Plan) from your child’s provider on file (this details what to do if your child has an allergic reaction)
• Provide your child’s school or daycare with an epinephrine pen and any other medications your child might need

Can this be prevented?

There’s no specific way to prevent tree nut allergies. But some strategies to reduce your child’s risk include:

• Eating nuts regularly (as long as you’re not allergic to them yourself) if you’re pregnant or breastfeeding.
• Asking your baby’s healthcare provider when and how to introduce new foods (they may recommend introducing your child to common allergens earlier than usual or under the supervision of a provider, depending on your child’s other health conditions)
• Making sure your child eats foods containing tree nuts regularly if you’ve safely had them eat nuts and know they aren’t allergic (this might reduce their risk of developing an allergy later on)

Are coconuts a tree nut?

No, coconuts are a fruit. In the U.S., they’re not considered a major allergen. Most people who are allergic to tree nuts aren’t allergic to coconuts.