An Overview of Peanut Allergies

How you can understand and cope with this common condition

In This Article

peanut allergy
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A peanut allergy can cause a mild stomachache, a rash, or it may cause life-threatening breathing or heart problems. It isn't clear why some people develop peanut allergies, but these reactions can develop due to exposure to tiny amounts of peanut residue.

There are medical ways to reduce the effects of a peanut allergy after they occur, but the best way to stay safe is to avoid peanuts and products that contain peanuts.

Peanut allergies are the third most common food allergy affecting American children and the second most common food allergy affecting American adults. Nearly 2% of children and 0.6% of adults in the U.S. are allergic to peanuts. This allergy is not as prevalent in other parts of the world, and the reason is unclear.

Even if you don't have a peanut allergy, you are likely to interact with people who could develop a serious reaction to peanut exposure. The more you know, the safer everyone will be.

Symptoms

While peanut allergies tend to begin during childhood, they can start at any age. More severe reactions typically to begin at an earlier age. Few children outgrow their peanut allergies during adolescence or adulthood, and about 80% continue to experience peanut allergies throughout their whole lives.

Effects of a peanut allergy usually begin immediately after exposure to peanuts or to peanut-containing products. The symptoms usually start within a few minutes after exposure but may take as long as two hours to appear.

Peanut allergy symptoms may include:

  • Skin reactions such as rash, hives or eczema
  • Gastrointestinal (GI) symptoms like nausea, stomach pain, vomiting, or diarrhea
  • Watery eyes, coughing, or a runny nose

Severe Reactions

Peanut allergies can cause life-threatening reactions. These reactions may be preceded by skin, GI or upper respiratory symptoms, or they can begin suddenly.

Signs of a life-threatening peanut induced reaction include:

  • Upper respiratory symptoms including coughing, or a runny nose
  • Wheezing
  • Swelling, also known as angioedema, of the lips, tongue, face, or throat
  • Severe reactions, called anaphylaxis, may occur, causing lightheadedness, trouble breathing, or loss of consciousness

Peanut allergies are more likely than other food allergies to cause anaphylaxis. Anaphylaxis is a medical emergency that requires prompt treatment.

Most of the deaths related to food allergy are associated with peanut ingestion and anaphylaxis.

Causes

Peanut allergies are caused by exposure to peanuts. Some people develop an allergic reaction from eating peanuts, others from touching, and others from inhaling the tiny protein particles in the air. The residue can be present on surfaces or in the air long after the actual peanuts have been removed.

You or your child may develop an allergic reaction after one or more of these types of peanut exposure.

Risk Factors

Experts aren't sure why some people develop peanut allergies. There are a number of common theories. There may be a hereditary link, and it is not uncommon for a person who has peanut allergies to have other family members with peanut allergies.

It has been suggested that exposure to certain foods or products could predispose to peanut allergies. However, there is not any specific product exposure that has been verified as a cause or trigger of peanut allergies.

There is a slight association between soy-based baby formula and the later development of peanut allergies. But soy-based baby formula is frequently used for babies who can't tolerate breast milk or regular formula, so experts aren't sure whether the peanut allergies begin before or after babes start using soy-based formula.

Allergic Reaction

The allergic reaction to peanuts occurs in response to proteins that are found in peanuts. The body mistakes these proteins as something harmful and mounts a rapid inflammatory response.

The inflammatory response causes the body to attack itself—resulting in the symptoms such as rash, wheezing, and GI upset.

There are various methods used in preparing peanuts, and some peanut allergies may be related to the preparation methods. However, if you have had a peanut allergy to peanuts prepared by one method, it is not considered safe to eat peanuts that were prepared by a different method.

Diagnosis

Your own observations are very important when it comes to recognizing a peanut allergy. If you have noticed that you have a reaction such as swelling or watery eyes after peanut exposure, then it is highly likely that you have a peanut allergy.

However, even after having any reaction, including an anaphylactic reaction, it may not be clear that peanuts were to blame. Peanuts may be hidden in both food and non-food items, so identifying them as the culprit can be challenging if you were exposed to a less obvious source of peanuts.

A food diary can be a good way to identify the triggers that cause your reaction. Keep in mind that if it isn't certain that your reaction is associated with food, your doctor may also ask you to record other environmental exposures, like detergents or the locations where you went each day.

Along with a food diary, you may try an elimination diet, in which you eliminate one food for several weeks and record and observe your reaction.

Your doctor may use several methods of diagnosing your peanut allergy. You will have a detailed medical history and a physical examination. Additionally, you may have food allergy testing.

Food Allergy Testing

Food allergy testing can include a number of approaches, including blood tests and skin prick tests.

A skin prick test, also called a scratch test, is when your doctor applies an allergen (something that can provoke an allergy) to your skin to observe if a rash or other reaction occurs. You can be tested for more than one allergen at a time using several regions on your skin.

A blood test can identify inflammatory proteins, such as IgE, which is an immune protein commonly associated with allergies.

Treatment

The treatment for peanut allergy is the elimination of peanut and peanut products from the diet. However, if you are exposed to peanuts, there are treatments that can alleviate your allergic reaction.

If you develop a skin reaction, you may be given a prescription for a lotion, cream, or oral medication to ease the reaction. Similarly, you may be given a prescription to reduce your GI symptoms.

Emergency Treatment

You should seek emergency medical care immediately for an anaphylactic reaction. Your doctor may also give you a prescription medication that you can use in case you develop problems breathing, angioedema, or lightheadedness as a result of peanut exposure.

Epinephrine is the most common emergency treatment for an anaphylactic reaction. Typically injected using an EpiPen, epinephrine can quickly stop some allergic episodes.

If you are prescribed an EpiPen, it is important that you have it with you at all times because you may unexpectedly be exposed to peanuts. Keep in mind that it is not safe to deliberately expose yourself to peanuts with the intention of using an EpiPen because your reaction may be too severe or might not respond to the medication.

In some instances, emergency medical attention may be needed even after you have used an EpiPen. You may need treatment for prolonged respiratory, cardiac, or other systemic problems.

Be sure to talk to your doctor so you will know exactly what you need to do if you develop a life-threatening reaction to peanuts.

Desensitization

Immunotherapy for peanut allergy involves a process of desensitization to peanuts. This is achieved by exposure to microscopic amounts of peanut protein, with the intention of eventually diminishing your body's inflammatory reaction to peanut protein. This type of treatment is not standard and is usually used in research studies or in university settings.

Because of the risk of a severe allergic reaction, you can only have desensitization treatment while under medical care and you should never attempt desensitization on your own.

Related Conditions

Peanut allergies are associated with several other types of allergies. This is described as a cross-reaction or cross-sensitization. It happens when the protein that induces an allergy in one product (such as peanuts) is also present in another product. It can also happen if the body has the same allergic reaction to two similar proteins.

Tree nut allergies affect about 30% of those who have peanut allergies. Tree nuts include almonds, macadamia nuts, brazil nuts, cashews, walnuts, pecans, pistachios, chestnuts, hazelnuts, and pine nuts.

Peanuts are a legume (a type of bean), but it is rare to have bean allergies along with peanut allergies. About 5% of those with peanut allergies may have an allergy to legumes such as soybeans, chickpeas, peas, and lentils.

The most common allergy associated with a peanut allergy is a reaction to lupine beans (also called lupin), which affects approximately 50% of those with peanut allergies. Lupine is eaten as a middle eastern and Mediterranean snack and it is not uncommon in European cooking and baking. While this food has not been well-known in the U.S., it is becoming more prevalent as an ingredient used in high protein, gluten-free, and specialty food products.

If you have a peanut allergy, you don't necessarily need to avoid potential cross-reactive foods out of fear of developing an allergy to them. Talk to your doctor about which foods are safe for you to consume.

Coping

Living with a peanut allergy can be stressful, but there are ways to cope. Avoiding peanuts can be a challenge, especially in places that are known for serving them, such as airplanes.

And since children with peanut allergies spend most of their waking time in school, managing peanut exposure and planning an emergency treatment plan while they are at school is important.

How to Avoid Peanuts

In addition to eliminating peanuts from your diet, it is equally important for some people to avoid all foods that could be Cross-contaminated with peanuts in the manufacturing process, such as granola bars, cookies, crackers, and cereals.

The Food Allergy Labeling and Consumer Protection Act (FALCPA) requires manufacturers to list peanut as a potential allergen ingredient for the consumer. Not only will you find this information in the ingredients list, but it will also be elsewhere on the package. If you can't find the information anywhere on the package, you can call the manufacturer and inquire about the specific ingredients contained in the product, and/or skip eating the product.

Cross-contamination can occur when trace amounts of peanut touch products that are made in the same facility. Due to this risk, many families will not bring foods into the home if they may have been prepared in a facility with peanuts.

These decisions are largely determined by the severity of the allergy and the type of exposure that causes it.

The following foods definitely contain peanuts:

  • Peanuts and peanut butter
  • Ground nuts
  • Mixed nuts
  • Artificial nuts (such as Nu-Nuts®)
  • Peanut flour
  • Cold-pressed, expelled or expressed peanut oil

Imported foods that contain hydrolyzed plant or vegetable protein may contain peanut oil. Foods made in the United States and Canada are required to list the source of these ingredients, but some imported foods may not list this information.

Peanut ingredients may be hidden in other foods or non-food items, such as:

  • Oils: Highly refined peanut oil is probably safe for most people with peanut allergies, but cold-pressed oil may contain higher levels of peanut proteins. Be careful when using highly refined oils, and be certain of the oil type and source before consuming.
  • International recipes: Peanut oil is commonly used in deep-frying and Asian cooking. Peanuts are nearly ubiquitous in Thai, Chinese, and Indonesian cooking. They are also common in West African and Southern American cuisine.
  • Cosmetics and creams: Peanut oil (labeled as arachis oil) may be found in cosmetics, medications, creams and topical products.

Heating peanuts or peanut butter may release proteins into the air that can cause a reaction for people who are sensitive to air-born peanut protein.

Be leery of the following categories of foods, as they may contain peanuts:

  • Caked goods, especially cookies, cakes, cupcakes, and crackers
  • Chocolates and candies, brittle, and barks
  • Ice cream and other frozen desserts
  • Spaghetti sauce, chili, soup, and similar dishes
  • Nougat and marzipan
  • Cereal and granola
  • Protein replacement drinks. shakes, or formula

If your baby has shown any signs of a peanut allergy, be sure to use hypoallergenic baby formula.

Many allergy-friendly manufacturers will state that their products are made in peanut-free facilities, so you can feel confident choosing products from those companies.

Managing a Peanut Allergy At School

Kids love peanut butter, and peanut butter and jelly sandwiches are a lunchbox staple. But peanut oil is sticky and it can cross-contaminate other foods and remain behind on lunch tables, hands, or drinking fountains. 

Schools deal with the risk of cross-contamination in different ways that include establishing separate lunch tables for allergic kids and banning peanuts from the entire school. What appears to be most challenging is balancing the needs of children with peanut allergies with the freedom of other children to eat their favorite foods.

Cleaning peanut residue off doorknobs, desks, and other items requires a daily cleaning routine.

Keeping the lines of communication open with the teachers and staff is the best approach to safeguarding children with peanut allergy. If your child has a peanut allergy, contact the school before the first day. Talk to the school nurse and teacher about a plan to keep your child safe at school. And learn more about peanut-free alternatives to the peanut butter and jelly sandwich.

Peanuts and Kissing

Because peanut butter is sticky, a person can have a reaction after kissing someone who has eaten peanuts. There is no way to wash the peanut protein out of one's mouth. Teenagers or adults who are dating should talk to their partners about their food allergy before kissing.

Flying with a Peanut Allergy

Many airlines now give out little packages of pretzels (or no snacks at all) instead of the classic airline peanuts. However, some airlines still hand out peanuts.

Before you fly, research the allergy policies of the airline that you intend to fly on. Some are prepared to accommodate guests with peanut allergies. Consider calling ahead to book a peanut-free flight or request a peanut-free meal.

A Word from Verywell

There is still no cure for a peanut allergy, so managing it involves strict avoidance of all peanut products and being prepared for possible reactions. If you have been diagnosed with a peanut allergy, be sure to have a plan in case you experience an emergency.

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