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. 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:

• Almonds;
• Brazil nuts;
• Cashews;
• Hazelnuts (including filberts, a type of hazelnut);
• Pecans;
• Pine nuts;
• Pistachios;
• Walnuts.

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 without warning, so carefully check the ingredients every time.

Tree nuts can be found in many foods and drinks, including:

• Cereals;
• Frozen desserts;
• Cold cuts like mortadella;
• Alcoholic drinks and liqueurs;
• Pesto;
• Nut extract;
• Nut oils;
• Marinades;
• Crackers;
• Cookies;
• Chocolate candy;
• Energy bars;
• Flavored coffees.

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 a possibility of cross-contact.

Tree nut oils and butter that contain nut protein should also be avoided. Tree nut oils are sometimes used in suntan lotions, shampoos, bath oils, and soaps.