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There are many kinds of tree nuts: almonds, cashews, and walnuts are well-known examples.
Tree nut allergies are a common type of food allergy for both children and adults.1 A tree nut allergy, like any allergy, is when your immune system identifies something you eat or come in contact with, as harmful. When you eat tree nuts, the proteins cause your immune system to respond and release histamine and other substances, which then cause your allergic symptoms. An allergy to tree nuts could result in anaphylaxis—a life-threatening allergic reaction. 2,3
Unfortunately, a tree nut allergy usually lasts a lifetime—fewer than 10% of people outgrow it.4 Some people who have previously had severe reactions to tree nuts will eventually outgrow their tree nut allergy. So, the severity of your reaction doesn’t necessarily mean you won’t outgrow the allergy.
Other symptoms of a tree nut allergy may include:
Tree nut allergies are among the most common causes of anaphylaxis.2,3 People with a severe tree nut allergy should be prepared to respond to an anaphylactic reaction at all times.
Learn more about anaphylaxis >
If you have an allergy to one type of tree nut, you have a higher chance of being allergic to other types of tree nuts, too.5 Plus, cross-contamination between multiple tree nuts is common during manufacturer processing. So, many people with an allergy to one tree nut avoid all tree nuts.
The most widely eaten kinds of tree nuts include:
Tree nuts can also be a hidden ingredient in many foods—this is why it’s important to read the label or ask about ingredients before buying or eating certain foods. Ingredients in packaged foods can change at any time—and without warning—so carefully check the ingredients every time.
Tree nuts can be found in many foods and drinks, including:
Cold cuts like mortadella
Alcoholic drinks and liqueurs
Because of their frequent use of nuts, Chinese, African, Indian, Thai and Vietnamese restaurants, ice cream parlors and bakeries are considered high-risk for people with a tree nut allergy. Even if you order a tree nut-free item, there is the possibility of cross-contact.
Tree nut oils and butters that contain nut protein should also be avoided. Tree nut oils are sometimes used in suntan lotions, shampoos, bath oils and soaps.
Cross-reactivity is when the proteins in one food are similar to the proteins in another and your body's immune system sees them as the same. There is a high degree of cross-reactivity between cashew and pistachio and between walnut and pecan. Because of this, some healthcare professionals will advise you to avoid other tree nuts even if you only have a confirmed allergy diagnosis to one.6
There’s a lot of confusion between peanuts and tree nuts. Even though peanuts have the word “nuts” in their name, they are legumes, not nuts. More than half of tree nut allergic patients report an allergy to peanuts.7-9 And 1 out of 3 peanut allergic patients also report a tree nut allergy.10,11
People with a tree nut allergy also commonly avoid peanuts because of the likelihood of cross-contact or cross-contamination—when one food comes into contact with another food and their proteins mix—during the manufacturing process.
The level of tree nut antibodies in someone's blood can help determine the possibility of outgrowing the allergy.10 A simple blood test that measures these antibodies can help your healthcare professional determine whether or not you or your child are likely to outgrow a tree nut allergy. Knowing the true cause of your symptoms now may also help you avoid more serious issues in the future. For example, a food allergy reaction sends someone to the ER every 3 minutes.12