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Peanut Allergy


What is a peanut allergy?

A peanut allergy is a reaction by your child's immune system to peanuts. Our immune systems normally respond to bacteria or viruses that attack the body. A food allergy occurs when the body's immune system mistakenly believes that a harmless substance (such as proteins found in peanuts) is harmful. In order to protect the body, the immune system creates substances called antibodies to that food. The next time you eat that particular food, your immune system releases huge amounts of chemicals, such as histamines, to protect the body. This is what causes the symptoms.

Peanuts are among the 8 foods that are responsible for most food allergies in children. The other foods include milk, soy, eggs, tree nuts (such as walnuts and cashews), wheat, fish, and shellfish. Many children grow out of food allergies to egg, milk, or soy, but only about 20% of children will outgrow a peanut allergy.

Most healthcare providers warn not to feed your child shellfish and food containing peanuts and tree nuts, until age 2. If you have family history of allergies, some recommend waiting until 3 years.

What are the symptoms of an allergic reaction to peanuts?

If you think your child is allergic to peanuts or any other food, it is important to get a diagnosis from your healthcare provider or allergist. Symptoms can be severe:

  • skin reactions such as itching, hives, eczema, or swelling
  • diarrhea, nausea, vomiting, stomach pain or itching around the mouth
  • runny nose, wheezing, or trouble breathing
  • rapid heartbeat.

With peanut allergy, it is more common to have an allergic reaction called anaphylactic shock. This is a serious reaction that is sudden, severe, and can involve the whole body. It can cause swelling of the mouth and throat, dangerously lower blood pressure, and trouble breathing. This type of reaction is a medical emergency. It is treated with epinephrine (a medicine that is given by injection). Usually parents or caregivers of children who have severe allergic reactions carry their own shot kits, just in case of emergency.

An allergic reaction to a food usually starts within minutes but may be delayed 2 to 4 hours. It usually lasts less than 1 day. The more severe the allergy, the smaller the amount of food it takes to cause a reaction.

Is my child also allergic to other nuts?

Nuts such as walnuts, almonds, pecans and cashews grow on trees. Peanuts grow underground. About half of the people with peanut allergy are also allergic to tree nuts. Ask your healthcare provider if it is safe for your child to eat tree nuts.

How will this affect my child's diet?

The only way to not have a reaction is to completely avoid the food that causes the allergy symptoms. This includes peanuts and any food that contains peanuts. Many processed foods and restaurant foods contain peanut or peanut products. You will need to change the way you order, shop and prepare foods.

If you are breast-feeding, eliminate the food your child is allergic to from your diet. Food allergens can be absorbed from your diet and enter into your breast milk.

The first step is to learn to read labels and get familiar with ingredients that contain peanut products. Always ask about ingredients if you are not sure. Study the lists below to learn more about foods and ingredients to watch out for.

Ingredients to look for in food products

  • Peanuts
  • Peanut butter
  • Mixed nuts
  • Artificial nuts (often peanuts that have be deflavored or reflavored)
  • Arachis (another name for peanut)
  • Lecithins or food additive 322
  • Satay (a peanut sauce)
  • Pure refined peanut oil, if properly processed, should not contain peanut protein and therefore should not cause reactions in allergic children. However, peanut oils are also available unrefined. Unrefined oils may be called cold-pressed, unprocessed, expelled or extruded oils. These unrefined oils may have peanut proteins and could cause allergic reactions. If in doubt, call the manufacturer.

Hidden source of peanuts

Cross contamination is a problem when trying to avoid peanut proteins. It is common for peanuts to come in contact with other foods during processing and in preparation, even if peanuts are not part of the recipe.

Items that could be contaminated with peanut

  • chocolate candies and ice cream
  • pastries, cookies and cakes where ingredients aren't listed
  • sauces such as barbecue and Worcestershire
  • mandelonas (peanuts soaked in almond flavor)
  • baking mixes
  • gravy
  • pesto (an Italian sauce made with nuts)
  • praline and nougat
  • cereals
  • baking mixes
  • prepared salads and salad dressings
  • hydrolyzed vegetable protein (usually soy based, but may come from any non-animal source) emulsified ingredient (may have been thickened with peanuts)
  • Asian foods (such as, satay, pad thai, and egg rolls), African, Chinese, Mexican, Tai, Indonesian and Vietnamese foods often use peanuts to flavor sauces or as a garnish.

When dining out:

  • Order simple dishes with only a few recipe ingredients. Avoid sauces unless you're sure they don't contain nuts.
  • Tell the waiter or waitress about the allergy.
  • Ask if food processors, cutting boards, pans, knives, or other food preparation equipment is used for nuts and for other foods.

Reading labels to avoid allergens has become a lot easier. Foods that contain milk, eggs, fish, shellfish, peanuts, tree nuts, wheat, or soy products must list the food in plain language on the ingredient list. For example, food additive 322 (peanut). These possible allergens must be listed even if they are part of a flavoring, coloring, or spice blend. There are still some things to watch out for when reading food labels:

  • Read the label every time. The manufacturer may change ingredients.
  • Watch out for the words “may contain”. Milk, peanuts, or other allergens may not be ingredients, but the food may be made in a factory that also produces these foods. If you see the words “may contain”, there may be very little of the allergen, or there may be a large amount.
  • Words on the package such as “peanut free” or “milk free” do NOT mean that the food is completely without these allergens. You still need to read the label carefully to make sure that it does not contain ingredients derived from allergens.

It is very important for you to know less common names and scientific names for food ingredients.

How can I provide my child with a healthy diet that tastes good?

Your child can still have a healthy diet. The main nutrients found in peanuts are protein, healthy fats, fiber, vitamin E, magnesium, and folate. There are many other foods that have the same nutrients as peanuts. The challenge is not providing a healthy diet, but to keep your child from unknowingly eating foods that contain them.

You can bake desserts from scratch or from mixes that do not contain peanuts. Some ice cream and chocolate companies make products without peanuts and that have been processed separately from those prepared with peanuts to eliminate the risk of cross-contamination. This would be stated clearly on the label.

How can I keep my child safe at school?

  • Teach your child not to eat foods unless they are safe. Even young children can grasp this concept, especially once they have gotten sick after eating a particular food.
  • Prepare your child's lunch at home.
  • Talk with teachers and the school administrator regarding your child's needs. Ask teachers to keep an eye out and explain the situation to other children if needed.
  • Have the teacher call you if there is a special event or party planned so that you can bring a few modified treats that your child enjoys and can share with other kids.
  • Make a card that lists foods and ingredients that should be avoided and give one to the teacher. The card can also be helpful to older children in making decisions when out with friends.
  • Children who have had life-threatening anaphylactic reactions before should keep injectable epinephrine (such as EpiPen) and an antihistamine (such as Benadryl) with them at all times.

Treating a food allergy with drops or shots that contain some of the allergen is called immunotherapy or desensitization. This may allow those with food allergies to eat the food or have a decreased allergic reaction to the food. The process can take a few years. Studies have shown some success for treating peanut allergy in this way. Much more research needs to be done to know if this is a safe and effective way to treat food allergies.

New evidence also shows a way to predict your child’s growing out of the peanut allergy based on the size of wheal (red bump) seen after a skin prick test. Ask to have your child re-tested after they reach the age of 5 years old.


Written by Terri Murphy, RD, CDE for RelayHealth.
Published by RelayHealth.
Last modified: 2010-02-03
Last reviewed: 2010-01-11

This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a health care professional.

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