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Nut and Peanut Allergy

Reviewed by: Magee Defelice, MD

What Are Peanut and Tree Nut Allergies?

Peanuts are among the most common allergy-causing foods, and they often find their way into things you wouldn't expect. Take chili, for example: It may be thickened with ground peanuts.



What Happens With a Tree Nut or Peanut Allergy?


Even a small amount of peanut or tree nut protein can set off a reaction. But allergic reactions from breathing in small particles of nuts or peanuts are rare. That's because the food usually needs to be eaten to cause a reaction. Most foods with peanuts in them don't allow enough of the protein to escape into the air to cause a reaction. And just the smell of foods containing peanuts won't cause one because the scent doesn't contain the protein.

What Are the Signs & Symptoms of a Nut Allergy?


This can cause symptoms such as:

  • wheezing
  • trouble breathing
  • coughing
  • sneezing
  • hoarseness
  • throat tightness
  • stomachache
  • vomiting
  • diarrhea
  • itchy, watery, or swollen eyes
  • hives
  • swelling
  • a drop in blood pressure
  • dizziness or fainting
  • anxiety or a feeling something bad is happening


How Is an Allergic Reaction Treated?

Nut and peanut allergies can cause a severe reaction called anaphylaxis. Anaphylaxis may begin with some of the same symptoms as a less severe reaction, but then quickly get worse, leading someone to have trouble breathing, feel lightheaded, or to pass out. If it is not treated right away, anaphylaxis can be life-threatening.

If you have a peanut or tree nut allergy (or any kind of serious food allergy), the doctor will want you to carry an epinephrine auto-injector in case of an emergency.

An epinephrine (pronounced: eh-puh-NEH-frin) auto-injector is a prescription medicine that comes in a small, easy-to-carry container. It's easy to use. Your doctor will show you how. Keep the epinephrine with you, not in a locker or in the nurse's office.

Every second counts in an allergic reaction. If you start having serious allergic symptoms, like swelling of the mouth or throat or trouble breathing, use the epinephrine auto-injector right away. Also use it right away if your symptoms involve two different parts of the body, like hives with vomiting. Then call 911 and have someone take you to the emergency room. You need to be under medical supervision because even if the worst seems to have passed, a second wave of serious symptoms can happen.

The doctor can also give you an allergy action plan, which helps you prepare for, recognize, and treat an allergic reaction. Share the plan with anyone else who needs to know, such as relatives, school officials, and coaches. Also consider wearing a medical alert bracelet.

Keeping epinephrine on hand at all times should be just part of your action plan. It's also a good idea to carry an over-the-counter (OTC) antihistamine as this can help treat mild allergy symptoms. But never use as a replacement for epinephrine shot in life-threatening reactions. Always use the epinephrine shot as the first treatment.

Living With Peanut or Tree Nut Allergy

If allergy skin testing shows that you have a peanut or tree nut allergy, an will provide guidelines on what to do.




  • "may contain tree nuts"
  • "produced on shared equipment with tree nuts or peanuts"

People who are allergic to nuts should avoid foods with these statements on the label. Although these foods might not use nut ingredients, the warnings are there to let people know the food may contain small traces of nuts. That can happen through something called "cross-contamination." This is when nuts get into a food product because it is made or served in a place that uses nuts in other foods. Manufacturers are not required to list peanuts or tree nuts on the label when there might be accidental cross-contamination, but many do.



Always be cautious. Even if you've eaten a food in the past, manufacturers sometimes change their processes — for example, switching suppliers to a company that uses shared equipment with nuts. Because ingredients can change, it's important to read the label every time, even if the food was safe in the past. And two foods that seem the same might also have differences in how they're made.

What Else Should I Know?

Here are other things to remember:

  • Tell everyone who handles the food you eat, from relatives to restaurant waitstaff, that you have a nut allergy. If the manager, chef, or owner of a restaurant is uncomfortable about your request for peanut- or nut-free food preparation, don't eat there.

Living with a food allergy can seem hard at times. But as more and more people are diagnosed with food allergies, businesses and restaurants are increasingly aware of the risks they face.

If friends you're visiting or eating lunch with don't know about your food allergy, tell them in plenty of time to make some simple preparations (such as not sharing your drink after eating that peanut butter sandwich!). Chances are, they'll understand. As your friends, they probably hope you'll be as considerate when it comes to taking care of them!

Reviewed by: Magee Defelice, MD
Date reviewed: August 2018