Peanut Allergy

(Allergy, Peanut; Nut Allergy; Allergy, Nut)

by Marjorie Montemayor-Quellenberg, MA

Definition

A peanut allergy occurs when the body responds abnormally to peanuts. The reaction may range from mild to life-threatening. Even a very small amount of peanuts can lead to a serious reaction. Peanut allergy is seen especially in children.

This condition may be serious. It requires care from a doctor.

Causes

The allergy occurs when your body is exposed to peanut proteins. The body mistakes the proteins as harmful substances, and the immune system releases chemicals into the bloodstream, which causes symptoms.

Coming in contact with peanuts can occur by:

  • Eating peanuts, foods containing them, or foods that came in contact with them
  • Touching peanuts
  • Inhaling particles containing peanuts (eg, peanut flour)

Risk Factors    TOP

Risk factors include:

  • Age— Food allergies, like peanut allergy, are common in children.
  • Having other allergies (eg, other food allergies, hay fever)
  • Personal or family history of allergies
  • Atopic dermatitis (chronic inflammation of the outer layers of the skin)

Symptoms    TOP

Symptoms may include:

  • Hives (redness or swelling of the skin)
  • Itching or tingling of the mouth and throat
  • Diarrhea
  • Stomach cramps
  • Nausea
  • Vomiting
  • Shortness of breath or wheezing
  • Chest tightness
  • Runny or stuffy nose

Hives

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Symptoms that may be a sign of a very serious allergic reaction ( anaphylaxis) may include:

  • Closing of airways or swelling of throat (making it very hard to breathe)
  • Severe drop in blood pressure
  • Very fast pulse
  • Dizziness
  • Lightheadedness
  • Loss of consciousness

If you have a serious allergic reaction or are with someone who does, call 911 right away or go directly to the hospital’s emergency room.

Diagnosis    TOP

You may be referred to a doctor who specializes in allergies. The doctor will:

  • Ask about your symptoms
  • Take your medical history
  • Do a physical exam

Tests may include:

  • Skin prick test—The doctor will place a small amount of food particles on your forearm or back. He will then prick your skin with a needle to allow the particles to enter your skin. If your skin reacts (eg, develop a bump), then that may be a sign that you are allergic to that particular food.
  • Blood test—The doctor will take a sample of blood from you. The blood will be tested for an antibody called immunoglobulin E (IgE). IgE is a type of protein that the body makes when it is exposed to something to which it is allergic.

Food Diary

The doctor may ask you to keep a food diary. This means you will write down your experiences with food, such as your eating habits and symptoms. This may help the doctor figure out what food(s) may be causing your allergies.

Elimination Diet

The doctor may put you on an elimination diet to figure out which foods may be triggering an allergic reaction. If your doctor thinks you might be allergic to peanuts, she may ask you to remove peanuts from your diet for 1-2 weeks then add them back to your diet to see if you experience any symptoms. The elimination diet is only done under a doctor’s supervision.

Treatment    TOP

Talk with your doctor about the best treatment plan for you. Options include:

Avoid Peanuts

The best treatment is to avoid peanuts, foods containing them, and foods that may have been exposed to them. Always read ingredient labels. Even if you do not think the food contains peanuts, still check the label! Most food labels will state whether the factory where a food was made also processes peanuts. If offered homemade foods, always ask about the ingredients to check for the presence of peanuts or peanut oil.

Medication

If you do have a mild allergic reaction, you may be able to take antihistamines to reduce symptoms, like itching or hives. Talk with your doctor about medicines that are right for you.

Epinephrine Injection

For severe allergic reactions, you may need to inject yourself with a medicine called epinephrine. Epinephrine is injected using an auto-injector (eg, EpiPen, Twinject), which contains a syringe, needle, and a dose of the medicine. You inject the medicine into your thigh. It is a good idea to carry an auto-injector at all times.

For any severe reaction, call 911 or go to the emergency room right away.

Prevention    TOP

Although you cannot prevent a peanut allergy, you can help prevent a reaction. To help reduce your chance of a reaction, take these steps:

  • Avoid peanuts, peanut-containing products, and foods that were exposed to peanuts. For instance, when placing an order at a restaurant, ask the server if the dish contains peanuts or is cooked with items (eg, sauces or oils) that may contain the nut.
  • Read food labels as well as other labels (eg, medicine, make-up, face cream labels). You never know what items may contain peanuts.

Here are some foods that may contain peanuts or may have been made in factories that process peanuts:

  • Cookies
  • Pastries
  • Ice cream
  • Energy bars
  • Cereal
  • Bread
  • Salad dressing
  • Chocolate candies
  • Nut butters and oils
  • Sauces and gravies
  • Vegetarian food products (eg, veggie burgers)

The list may be endless. This is why it is very important to be aware of what you are eating or come in contact with. Even the smallest amount of peanut protein can trigger a life-threatening response.

RESOURCES:

American Academy of Allergy, Asthma, and Immunology
http://www.aaaai.org/
Food Allergy and Anaphylaxis Network
http://www.foodallergy.org/

CANADIAN RESOURCES:

Allergy Asthma Information Association
http://aaia.ca/
Calgary Allergy Network
http://www.calgaryallergy.ca/

References:

Lee CW, Sheffer AL. Peanut allergy. Allergy Asthma Proc. 2003;24(4):259-264.
Mayo Clinic Staff. Peanut allergy. Mayo Clinic website. Available at: http://www.mayoclinic.com/health/peanut-allergy/DS00710 . Updated August 23, 2010. Accessed August 24, 2011.
Nut and peanut allergy. KidsHealth website. Available at: http://kidshealth.org/kid/stay_healthy/food/nut_allergy.html# . Updated August 2008. Accessed August 24, 2011.
Peanut allergy. American College of Allergy, Asthma, and Immunology website. Available at: http://www.acaai.o... . Accessed August 24, 2011.
Peanut allergy. Asthma and Allergy Foundation of America website. Available at: http://www.aafa.org/display.cfm?id=9&sub=20&cont=517 . Updated 2005. Accessed August 24, 2011.
Peanut allergy. The Food Allergy and Anaphylaxis Network website. Available at: http://www.foodallergy.org/page/peanut-allergy . Updated August 18, 2011. Accessed August 24, 2011.
Last reviewed September 2012 by Purvee S. Shah, MD
Last Updated: 09/26/2012
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