Condition Basics

What is a peanut allergy?

A peanut allergy is a reaction that occurs when your body mistakenly identifies peanuts as a harmful substance. When you eat peanuts or food that contains peanuts, your body's immune system overreacts. This can cause a severe allergic reaction that may need immediate medical care.

What causes it?

It's not clear why peanuts trigger a reaction in some people. An allergic reaction occurs when your immune system overreacts and releases chemicals, including histamine, into your blood. These chemicals can affect different tissues in the body. These include the skin, eyes, nose, airways, intestinal tract, lungs, and blood vessels.

What are the symptoms?

Symptoms of peanut allergy can range from mild to severe. If you have a mild reaction, you may get:

• A stomach ache.
• A runny nose.
• Itchy eyes.
• Hives.
• Tingling in your lips or tongue.

Your symptoms may start from within a few minutes to a few hours after eating peanuts or peanut products.

People who are allergic to peanuts may have a dangerous reaction called anaphylaxis. Symptoms of anaphylaxis can include:

• Problems breathing and swallowing.
• Severe belly pain, nausea, vomiting, or diarrhea.
• Dizziness.
• Dangerously low blood pressure.
• Swelling of the lips, tongue, throat, and other parts of the body.
• Loss of consciousness.

Anaphylaxis can cause death if not treated. It usually occurs within minutes but can occur up to several hours after eating peanuts or peanut products.

How is it diagnosed?

To diagnose a peanut allergy, your doctor will start with a medical history and a physical exam. Your doctor will want to know about family members with food allergies, especially siblings with peanut allergies.

Your doctor will ask about your symptoms and how soon they started after you ate the food. They will ask if any over-the-counter allergy medicines like an antihistamine were helpful.

You may also have allergy tests, such as skin tests or blood tests.

It's important to find out whether you have a food allergy or food intolerance. You may be asked to keep a record of all the foods you eat and any reactions to the foods. Your doctor may also have you do an oral food challenge during your appointment so any reaction can be monitored and treated.

How is an allergic reaction to peanuts treated?

Avoiding any contact with peanuts, foods that contain peanuts, and peanut oils is the best treatment. But if you eat peanuts by accident, follow your doctor's instructions.

If you had a severe reaction in the past, your doctor probably prescribed a medicine called epinephrine. If you have symptoms in more than one body area, such as mild nausea and an itchy mouth, give yourself an epinephrine shot. Then call 911.

Even if you feel better after giving yourself the shot, symptoms of anaphylaxis can recur or suddenly appear hours later. You will need to be watched in a hospital for several hours after your symptoms go away.

If you do not have epinephrine and are having a severe allergic reaction, call 911 right away.

How can you prevent it?

This is how to prevent an allergic reaction to peanuts.

• Avoid peanuts.

  Avoid any contact with peanuts, foods that contain peanuts, and peanut oils.

• Understand your allergy.

  Be aware that you need to protect yourself. Read food labels or ask kitchen staff at restaurants if there are peanuts or peanut oils hidden in any of the foods you order. For example, some cooks thicken chili with peanut butter. Some people are so severely allergic to peanuts that being near them or breathing air that contains peanut residue can cause an allergic reaction.

• Let others know that you or your child has a peanut allergy.

  Make sure that all caregivers (such as school administrators, teachers, babysitters, and coaches), friends, and co-workers:

  • Know what the symptoms of an allergic reaction look like.
  • Know where the epinephrine shot is kept and how to give the shot.
  • Have a plan to transport you or your child to the hospital.
• Wear a medical alert bracelet or medallion that lists your allergy.

  This will alert emergency response workers if you have a severe allergic reaction.

• Keep your epinephrine shot with you at all times.

  Make sure older children know how to give you or themselves the shot. Talk with your doctor or pharmacist if you are unsure how to give yourself the shot.

• Keep other medicines with you if your doctor recommends it.

  This includes antihistamines used for mild reactions. Antihistamines are not a substitute for epinephrine in a severe allergic reaction.

If you think you are having an allergic reaction, get help. Do not minimize how serious this problem is. After you give yourself an epinephrine shot, call your doctor immediately or seek other emergency services. You will need to be observed for several hours to make sure the reaction does not recur.