Understanding Tree Nut Allergies: Symptoms, Treatment, and More

Medically reviewed by Judith Marcin, MD on November 20, 2017Written by Kimberly Holland on June 10, 2015

What is a tree nut allergy?

A tree nut allergy is one of the most common food allergies in both adults and children. Allergic reactions to tree nuts can range from mild (minor itching, watery eyes, and a scratchy throat) to life-threatening. You may be allergic to just one type of tree nut, or you could be allergic to several. Examples of tree nuts include:

  • almonds
  • walnuts
  • pecans
  • hazelnuts
  • pine nuts
  • lychee nuts

Being allergic to one type increases your risk for being allergic to others. Until your allergies are tested by your allergist-immunologist (a doctor who specializes in treating allergies and the immune system), you may be asked to avoid all tree nuts.

What are the symptoms of a tree nut allergy?

If you’re allergic to tree nuts and exposed to them, you may develop symptoms of an allergic reaction. In some cases, these symptoms will appear within minutes and be severe. In other cases, it may take 30 minutes to a few hours before symptoms begin.

Symptoms of a tree nut allergy may include:

Anaphylaxis is rare, but it’s the most severe form of allergic response. In the case of anaphylaxis, a person with an allergy will typically begin experiencing symptoms within 5 to 30 minutes of exposure to the tree nut. Symptoms of anaphylaxis include:

  • swollen throat
  • wheezing
  • passing out
  • trouble swallowing
  • vomiting
  • a red rash with hives or welts

Peanut, shellfish, and tree nut allergies are among the most common causes of anaphylaxis. People with a severe tree nut allergy should always be prepared to respond to an allergic reaction. You should always keep an epinephrine auto-injector with you. Common brands of auto-injectors include EpiPen, Adrenaclick, and Auvi-Q.

What are risk factors for tree nut allergies?

It’s important to know the risk factors associated with tree nut allergies. Here are some common risk factors.

Peanut allergy

Peanuts are not tree nuts, they are legumes, but being allergic to peanuts increases your risk for a tree nut allergy. In fact, 25 to 40 percent of people who are allergic to peanuts are also allergic to tree nuts, according to the American College of Allergy, Asthma & Immunology.

Other tree nut allergies

If you are allergic to one type of tree nut, you may be allergic to others. Your immunologist may choose to conduct a complete allergy screening test to figure out all your allergies.

Family history

If a parent or sibling has a tree nut allergy, other children and siblings are at an increased risk. A doctor can provide guidance on testing for allergies in families.

How are tree nut allergies diagnosed?

Tree nut allergies can be life-threatening. That’s why it’s so important to have a definitive diagnosis from an allergist. To diagnose your allergies, your allergist may conduct a skin prick test. During this test, your skin will be exposed to a variety of allergens. If you’re allergic to one of the allergens, your skin will react and swell or turn red. Your doctor may also recommend blood tests depending on your age and other medical conditions you have.

If the results of your tests are inconclusive, your doctor may request a food challenge. For this test, you will be exposed to the allergen (a specific food item) in increasing doses over several hours. Your doctor will supervise this test in case there is an allergic reaction. Emergency medication and services should be at hand during the test.

What foods should I avoid if I have a tree nut allergy?

Tree nut allergies cannot be cured. So, the best way to avoid a tree nut allergy reaction is to avoid them. Strict avoidance of nuts and products that might contain nuts should protect you against an allergic reaction. Many doctors will recommend that people, especially children, with a diagnosed allergy to one tree nut avoid all tree nuts because of the potential for an allergy to those as well.

The most widely consumed tree nuts include:

  • almonds
  • Brazil nuts
  • cashews
  • hazelnuts/filberts
  • macadamia nuts
  • pecans
  • pine nuts
  • pistachios
  • walnuts

Nut butters, nut oils, and natural nut extracts are also off limits for people with tree nut allergies.

In the United States, food manufacturers are required to list if their foods may contain allergens, including tree nuts. You should also read ingredient lists on food labels to be sure the food is allergen-free. Sometimes foods may come in contact with tree nuts during the manufacturing process. Food packaging also often lists that potential hazard.

However, don’t assume that a safe food will always be safe. Food manufacturers change their formulas regularly, and they may begin adding tree nuts without notice. That’s why it’s smart to read labels every time you pick up a food. You can never be too careful, especially if you have a severe allergy to tree nuts.

Hidden sources of tree nuts

Allergens can hide in products you may not suspect despite labeling guidelines imposed by the Food and Drug Administration (FDA). Tree nut proteins may be found in:

  • dry goods: cookies, cereals, crackers, protein or energy bars, and breakfast bars
  • desserts: candy, chocolates, ice creams, and frozen yogurts
  • beverages: flavored coffees, alcoholic beverages, and liqueurs
  • perishable goods: cold cuts, cheeses, marinades, and condiments
  • personal hygiene products: lotions, shampoos, perfumes, and soaps

Some restaurants may also use tree nuts in their recipes without labeling the food in the dish’s description. Communicating with your server is imperative when you’re dining in a restaurant.

What is life like with tree nut allergies?

The outlook for a tree nut allergy depends on two things: your age and your allergy severity. Adults diagnosed with a tree nut allergy should expect it to be lifelong.

For children, the outlook is a bit different. Some children will outgrow their food allergies, including an allergy to tree nuts. Unfortunately, compared with other allergies such as egg or milk, the number of children who outgrow their tree nut allergy is quite low, around 10 percent, according to one study. Children who are only mildly allergic to tree nuts (they don’t experience anaphylaxis when exposed to the allergen) have a better chance of outgrowing the allergy than children who have a very severe allergic reaction to tree nuts.

Thanks to increased societal awareness about food allergies, it’s now much easier for people with tree nut allergies to find safe foods and communicate with others about their allergies.

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