Peanut allergies

We really can’t leave National Peanut Butter Lover’s month without talking about peanut allergies. Peanut allergies are one of the most common food allergies in America.

(Photo from WebMD)

What causes an allergy?

Everybody has antibodies. These are produced by our white blood cells to help fight off bacteria, viruses, and other things that can cause disease. Sometimes antibodies get confused and instead of only responding to dangerous things (like bacteria), they will respond to things that are not dangerous (like proteins in food). Even though these food proteins are not normally dangerous, if an antibody reacts inappropriately, now it is dangerous to that person.

When an antibody finds a protein it thinks is dangerous, it causes the release of histamine and other chemicals from the inside of mast cells (a type of white blood cell). When histamine and the other chemicals are released from the mast cells, they go into the blood and cause the signs of an allergic reaction.

The Food Allergy & Anaphylaxis Network has a diagram of what happens in the mast cells during an allergic reaction.

(Image from the Food Allergy & Anaphylaxis Network.)

What are signs of an allergic reaction to peanuts?

Signs of a peanut allergy can happen anywhere from a few minutes to a few hours after eating peanuts. Signs can range from very mild (hives) to very severe (anaphylaxis).

• Hives, redness, or skin swelling
• Itching or tingling of the lips, mouth, or throat
• Stomach cramps, nausea, vomiting, or diarrhea
• Runny nose
• Tightening of the throat
• Shortness of breath or wheezing

In addition to those signs, the signs of anaphylaxis can also include:

• Airway constriction
• Throat swelling so it is hard to breathe
• Drop in blood pressure
• Fast heart beat
• Dizziness or lightheadedness
• Loss of consciousness

How is peanut allergy treated?

The best way to treat a peanut allergy is to completely avoid peanuts and foods that may contain peanuts. It is important to read every ingredient label. Some foods may not contain peanuts, but the label may have a warning that says something like “This food has been processed on the same equipment that handles peanuts.” This kind of food should also be avoided as it may contain small amounts of peanuts. Even a tiny amount of peanuts can be enough to cause a reaction in someone who is severely allergic.

The Mayo Clinic website and the Food Allergy & Anaphylaxis Network (FAAN) website have lists of foods that may contain peanuts. The FAAN website also has a printable reference card that can help you read ingredient labels to look for peanuts or peanut products.

Most mild allergic reactions can be treated with anti-histamines. This does not treat the allergy, but it does treat the symptoms (like hives and itchiness). An anaphylactic reaction to peanuts is life-threatening if not treated immediately. Someone having an anaphylactic reaction needs immediate treatment with epinephrine (EpiPen, or some other auto-injector) and to go to the emergency room.

Can people outgrow peanut allergies?

Approximately 20% of children will outgrow their peanut allergy. But this allergy can recur at any time in their lives. Because peanut allergies can be so severe, it is not safe to “test” the allergy by eating peanuts. You can ask your doctor to do allergy tests if you think you (or your child) may have outgrown a peanut allergy, but do not try to figure it out at home.

If I have a peanut allergy, will I be allergic to anything else?

If you have one allergy, it is likely that you will have more. About 35% of people who are allergic to peanuts are also allergic to tree nuts like walnuts, pecans, almonds, or any nut that grows on a tree (remember that peanuts are not actually nuts). If you are allergic to peanuts, it is likely that you will have other food allergies. You are also more likely to develop eczema or respiratory allergies (like hay fever) than someone without a peanut allergy.

If you think you, or someone in your family, has a peanut allergy you should make an appointment with your doctor. The Mayo Clinic’s website has a great list of questions that you should be prepared to ask (and answer) at your first doctor appointment.