If you or your child is allergic to nuts — either tree nuts or peanuts — you may live in mortal fear that errant nuts in a food you’d never expect to contain them will trigger an allergic reaction or even anaphylaxis. For people with severe allergies, eating nuts can even be fatal.

Related: The ABCs of Food Allergies in the Classroom

Nut allergies, common in both kids and adults, are among the most severe of all food allergies according to the American Academy of Pediatrics. Unlike some other food allergies, people tend not to outgrow a nut allergy. Only about 9 percent of children with a tree nut allergy outgrow it eventually, according to foodallergy.org, and about 20 percent of those with peanut allergy do, according to research from the National Institutes of Health.

Some people have allergies to both tree nuts and peanuts. Even people with allergies only to certain tree nuts should stay away from all tree nuts to be absolutely safe, experts advise.

Tree nuts include such nuts as walnut, almond, hazelnut, cashew, pistachio and Brazil nuts. Peanuts are classified as legumes.

Symptoms of a nut allergy

Symptoms of tree nut allergy may include abdominal pain, cramps, nausea and vomiting, difficulty swallowing, runny nose, shortness of breath and diarrhea. A severe allergy can cause anaphylaxis, a life-threatening reaction that can send the body into shock.

Symptoms of peanut allergy may also include nausea, runny nose and anaphylaxis, but also itchy skin or hives. There can be tingling in or around the mouth and throat.

If you suspect peanut allergy, start a food diary, and see an allergist. The doctor may put you on a food elimination diet to see if your symptoms go away as certain foods are removed. Peanut allergy can be difficult to pinpoint through blood tests or skin prick tests (placing a small amount of allergen on the skin to observe reaction).

For suspected tree nut allergies, your allergist may use skin prick tests or blood tests to look for antibodies that form in response to the allergen. Or he may do an oral food challenge, in which you eat tiny amounts of the food under close medical supervision.

Because nut allergies are so common, the Food Allergen Labeling and Consumer Protection Act of 2004 requires they be listed on food labels. And it’s important to read those labels, because nuts may lurk where you least expect them.

Related: Peanut Butter for Infants?

Hidden sources of peanuts

Some sources of peanuts are obvious — peanut butter, mixed nuts, nut pieces, peanut flour, beer nuts, mandelonas (peanuts soaked in almonds). Also avoid foods whose labels list “peanut protein hydrolysate.”

According to Food Allergy Research and Education, a nonprofit organization, these foods may also contain peanuts:

  • Artificial nuts (for instance, imitation almonds)
  • Baked goods
  • Candy (including some chocolate candy)
  • Chili
  • Egg rolls
  • Enchilada sauce
  • Marzipan
  • Nougat
  • Mole sauce

Some people with peanut allergy can safely eat highly refined (not cold pressed, for instance) peanut oil, since it contains little in the way of nut protein. But check with your doctor first.

At restaurants, among the unexpected source of peanuts are:

  • Sauces such as salad dressing, chili sauce, hot sauce, pesto and gravy
  • Pancakes
  • Pizza
  • Vegetarian products promoted as meat substitutes
  • Glazes, marinades

According to the American College of Allergy, Asthma & Immunology, people with a peanut allergy should also avoid foods with a precautionary statement on the label indicating the food may contain peanuts or may have been processed in a factory that also processed foods with nut ingredients.

Related: Exposing Babies to Peanuts May Help Curb Allergy Risk

Tree nuts

Among the possible hidden sources of tree nuts, according to Food Allergy Research & Education, are:

  • Cereals
  • Crackers
  • Cookies or candy
  • Chocolates
  • Energy bars
  • Flavored coffees
  • Frozen desserts
  • Marinades
  • Barbecue sauces
  • Mortadella (aka “Italian baloney”)
  • Alcoholic beverages with nut flavoring

Among tree nuts and foods with nuts that can provoke an allergic reaction:

  • Almonds
  • Brazil nuts
  • Beechnuts
  • Butternuts
  • Cashew nuts
  • Chestnuts
  • Chinquapin nuts
  • Artificial nuts
  • Coconut
  • Hazelnuts or filberts
  • Ginkgo nuts
  • Hickory nuts
  • Litchi or lychee nuts
  • Macadamia nuts
  • Almond paste or marzipan
  • Nangai nuts
  • Nut extra (almond, walnut)
  • Nut butters such as cashew butter
  • Nut meal or meat
  • Nut milk, paste or pieces
  • Pecans
  • Pesto
  • Pili nuts
  • Pine nuts
  • Pistachio nuts
  • Praline
  • Shea nuts
  • Walnuts

Tips for the nut allergic

Besides reading labels carefully and watching what, and where, you eat when you dine out, you can take other measures to minimize the risk of a reaction to nuts.

Wear an allergy alert bracelet. Ask your doctor if you or your child should consider this bracelet. This will help paramedics in case you lose consciousness in the midst of an attack.

At restaurants, talk to the waiter. Be sure the waiter knows you or your child has a nut allergy. Ask if the dish you have in mind has any nut as an ingredient or if it was prepared with dishes that do. If the waiter seems unsure, skip it. According to the American College of Allergy, Asthma & Immunology, be especially wary at Asian and Mexican restaurants, where peanuts are common ingredients.

Ask your doctor about carrying an epinephrine autoinjector for you or your child. Use it as your doctor directs, usually at the first sign that you or your child is having an allergic reaction.

Be sure your friends and family are informed. They should know to call 911 for an ambulance if you or your child is having a severe reaction. You need this medical help even if you used the autoinjector.

Related: Hidden Food Allergens: 18 Surprising Foods (and Drinks) That Have Them

Kathleen Doheny is a Los Angeles journalist specializing in health, behavior and fitness topics.