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Peanut Allergy

When the topic of peanuts comes up, people sometimes wonder about peanut allergies. This article aims to answer common questions about peanut allergies and provide resources for further learning.

What is a Peanut Allergy?

A peanut allergy occurs when a person’s immune system mistakenly recognizes peanut protein as an allergen. The major proteins Ara h 1, Ara h 2, and Ara h 3 are the allergens in peanuts, but at least 7 proteins have been identified as potential allergens. Having any food allergy requires strict avoidance of the food in the diet. Treatment generally includes the avoidance diet and symptom treatment when accidental ingestion occurs. In addition, the FDA has approved oral immunotherapy (OIT), called Palforzia, to treat peanut allergy.

The groundbreaking LEAP Study (2015) found that the introduction of peanuts into an infant’s diet, prior to 11-months old, reduced the prevalence of peanut allergy significantly. As a result of the LEAP study, new guidelines have been released to encourage early introduction of peanut foods. Research has shown that introducing peanut foods early to those infants who are at high risk reduced rates of developing peanut allergies by up to 86%. Implementing early introduction will hopefully reduce the prevalence of peanut allergies for future generations.

How Many People are Allergic to Peanuts?

With increasing news coverage on peanut allergy in the past few years, there may be a misperception about the actual prevalence of peanut allergy in the U.S. It is thought that 1-2% of Americans have a peanut allergy. Studies show that up to 20% of peanut allergies may be outgrown. However, the true prevalence of food allergies is unknown, since most data is collected through self-report and may not be accurate. Those with a family history of allergy, asthma, or eczema, may be at increased risk.

Both genetic and environmental factors appear to be involved. Having severe eczema and having an existing egg allergy makes children more likely to develop a peanut allergy. Family history of allergy may also be a factor.

Why Are People Allergic to Peanuts?

An allergic reaction is caused by a dysfunction in the immune system. Individuals may experience allergic reactions to foods, insect venom, latex, and a variety of environmental exposures. A food allergy reaction involves the immune system and occurs when a typically safe substance in foods, usually a protein, unnecessarily, triggers the body’s protective immune response. Reactions can range from mild to severe.

The Centers for Disease Control and Prevention (CDC) reports that children with food allergies are more likely to have asthma or other allergic conditions. Nearly 90% of food allergies are caused by these common foods: tree nuts (almonds, walnuts, pecans, cashews, pistachios, etc.), peanuts, milk, eggs, fish, crustacean shellfish, wheat, and soy.

Signs of Food Allergy

Fortunately, most allergic reactions are not life-threatening, but any food allergy reaction can be severe and unpredictable. Reactions can range from hives that quickly go away on their own to a reaction called anaphylaxis that may involve the respiratory and cardiovascular system and can be life-threatening. Food allergy reactions can include any organ system. The only recommended treatment for anaphylaxis is epinephrine. Diagnosing a food allergy should be done by a board-certified allergist and may include blood or skin tests based on a known history of reactions after eating a certain food. If a food can be eaten without provoking symptoms, then an individual does not have an allergy to that food. For more information on treating a food allergy reaction, speak with your pediatrician or physician.

Levels of Peanut Allergies

  • How is allergy severity measured?
  • What is considered a mild allergy? What is considered severe?
  • What class of allergy is most common?

Reference: During peanut component allergen testing the presence of IgE antibodies specific for potentially allergenic individual proteins, namely Ara h 1, Ara h 2, Ara h 3, Ara h 6, Ara h 8, Ara h 9, and profilin protein Bet v2, are assessed. The determination of the relative amount of IgE antibody to specific peanut components can aid in assessment of the potential strength and type of allergenic response (see Table below).


ClassIgE kU/LInterpretation 
0/10.10-3.4Borderline/ Equivocal
417.5-49.9Strongly positive
550.0-99.9Strongly positive
6> or =100Strongly positive

Allergic reactions to peanuts can range from the mild to severe. Symptoms of a mild allergy, for example, could include things like a runny nose, itchiness, and/or nausea. Severe allergies, however, can result in anaphylaxis — a potentially life-threatening reaction that can cause impaired breathing, a drop in blood pressure, swelling of the throat, blue lips, pale skin, dizziness and fainting.

Eating Peanuts During Pregnancy

For expectant mothers, limited evidence suggests that eating peanuts during pregnancy may help to reduce the risk of a peanut allergy in the child. The Growing Up Today Study (GUTS) examined 10,907 children whose mothers provided dietary information while they were pregnant and within one year of pregnancy. Peanut allergies were significantly lower in the children of 8059 nonallergic mothers who consumed more peanuts than those who did not. More evidence is needed in this area. Maternal peanut consumption during pregnancy or lactation had no effect on developing allergy in one study, nor did duration of breastfeeding. The American Academy of Pediatrics recommends that pregnant mothers eat a diverse diet and does not recommend avoiding any allergen as a way to prevent food allergies.

The Risk of Casual Contact

In those who are especially sensitive, reactions to peanuts can occur from ingesting just a trace amount. This can cause anxiety, especially for the parents of peanut-allergic children. However, research shows that touching, smelling or just being near peanuts is highly unlikely to cause a severe reaction (Simonte SJ, et al. Relevance of casual contact with peanut butter in children with peanut allergy. J Allergy Clin Immunol. 2003 Jul:112 (1): 180-2.)

Smelling the aroma of peanuts is not the same as inhaling airborne peanut particles that could potentially contain the allergenic protein. The aroma of peanuts comes from volatile compounds that cannot cause an allergic reaction. Also, highly refined peanut oil is not required to carry allergen labeling because the process used to purify the oil removes the protein, thereby making it no longer allergenic.

In one controlled study, 30 children with significant peanut allergy were exposed to peanut butter, which was either pressed on the skin for one minute, or the aroma was inhaled. Reddening or flaring of the skin occurred in about one-third of the children, who had the peanut butter applied to the skin, but none of the children in the study experienced a systemic reaction.

Peanut Allergy Management Tips

To prevent an allergic reaction it is essential to avoid eating the allergenic food. Here are some tips to minimize the risk of accidental ingestion:

  1. Read labels every time, even if the food has been eaten safely in the past, since manufacturers can change their formulations. Look for a “contains” statement and read the ingredient list, since manufacturers can list allergens in either place.
  2. Plan ahead when dining out or attending a party. Call ahead to talk with restaurant staff, or use a “chef card,” which lists ingredients to avoid and can be found at the Food Allergy Research & Education (FARE) website at https://www.foodallergy.org/resources/food-allergy-chef-cards.
  3. Keep surfaces clean by using common household cleaning agents that have been proven to remove proteins after potential allergens have touched them.
  4. Carry medicine such as epinephrine auto-injectors. Epinephrine is life-saving medication that should be used any time anaphylaxis is suspected. Always call 911 after using epinephrine to treat anaphylaxis as a second reaction may occur and additional medical care could be needed.
  5. Control asthma with proper medical care since asthma is a significant risk factor for death due to anaphylaxis.
  6. Let people know about your allergy by wearing an emergency alert bracelet or necklace identifying the allergy and its severity.

Foodservice professionals should also take special care to minimize the risk of exposure to food allergens for food allergic individuals. Some strategies for reducing exposure to food allergens in the foodservice setting include:

  1. Training staff on handing foods that can cause allergy
  2. Sanitizing equipment and workspaces to avoid cross contamination during food preparation
  3. Posting signs in appropriate areas when foods with allergens are served
  4. Properly labeling any in-house packaged foods that contain allergens
  5. Having a plan for readily accessing emergency medical care.

Food Allergen Bans

Evidence does not support the effectiveness of food bans as a means to prevent food allergy reactions in food service environments. In fact, many experts feel that food bans, except in situations that involve very young children such as in daycare centers, give a false sense of security. Peanut bans, for example, ignore other potentially serious food allergies. Schools can help children with food allergies prepare for managing real-world environments while offering a safety net. A comprehensive food allergy management plan is recommended and includes preparedness and training of faculty, school food service personnel, parents and students on how to manage food allergies is thought to be the most effective approach.

What Causes a Peanut Allergy and Allergic Reactions to Peanuts?

The science is not clear as to what causes peanut allergy. Both genetic and environmental factors appear to be involved. The groundbreaking LEAP Study (2015) found that the introduction of peanuts into an infant’s diet, prior to 11-months old, reduced the prevalence of peanut allergy significantly. As a result of the LEAP study, new guidelines have been released to encourage early introduction of peanut foods. Research has shown that introducing peanut foods early to those infants who are at high risk reduced rates of developing peanut allergies by up to 86%. Implementing early introduction will hopefully reduce the prevalence of peanut allergies for future generations.

Oral Immunotherapy Shows Promise for Treatment of Peanut Allergy

Recent research shows that oral immunotherapy (OIT) may be an effective means by which to reduce a patient’s reactivity to the peanut allergen. Oral immunotherapy induces the body’s immune system to tolerate a food that it is currently overreacting to. This is done by consuming extremely small quantities of the allergen on a regular basis, in gradually increasing amounts. Previous randomized, controlled clinical trials have provided evidence that daily peanut OIT can reduce the severity of allergic reactions to peanuts. The most recent research suggests that early OIT in preschool-aged children is most effective. A study published in the Journal of Allergy and Clinical Immunology showed that 91% of children aged 9-36 months were able to tolerate 5 grams of peanut protein (the equivalent of about 20 peanuts) after OIT These findings demonstrate that OIT is an effective way to disrupt peanut allergy in young children. Studies currently underway are examining whether this desensitization effect of OIT on peanut allergy is permanent, or if it requires “maintenance” to prevent the occurrence of allergic reactions.

Schools: To Ban or to Educate?

Most allergy advocacy groups do not support school food bans. In fact, research published in the Journal of Allergy, Asthma, & Immunology shows that banning peanuts in schools or in classrooms has no effect on the incidence of allergic reactions, as measured by incidence of epinephrine administration. Many experts feel that a ban gives a false sense of security, and a ban may not keep all peanut products entirely out of schools. Instead, experts say it is important for school age children to learn to manage their allergy in all environments, and recommend that schools develop plans to effectively manage peanut allergies. Food Allergy Research & Education (FARE), the leading national organization working on behalf of the 15 million Americans with food allergy, recommends that “parents, doctors, and school officials work together and develop a plan that best fits their situation.” By educating parents, physicians, school administrators, teachers, school nurses, kids in the classroom, and others in the child’s environment, a safety net can develop around a child with a peanut allergy. FARE and other organizations have developed a variety of resources and products to help to keep children with food allergies safe.

 Is Peanut Oil Allergenic?

There are two types of peanut oil – highly refined peanut oil and unrefined, or gourmet, peanut oil. Both are extracted from peanuts, but the way they are processed results in two quite different oils. Highly refined peanut oil, the type used in most restaurants and for frying, does not contain the proteins that cause reactions, while unrefined peanut oil does.

When highly refined, the proteins in the oil that can cause allergic reactions are removed. The vast majority of peanut oil used in foodservice and by consumers in the U.S. is processed and is considered highly refined. The FDA exception for highly refined oils is as follows:

The FDA Food Allergen Labeling and Consumer Protection Act of 2004 and the Federal Food, Drug, and Cosmetic Act (FFDCA) indicate that highly refined oils are not major food allergens.

The Federal Food, Drug, and Cosmetic Act states:
“(qq) The term `major food allergen’ means any of the following:

  1. Milk, egg, fish (e.g., bass, flounder, or cod), Crustacean shellfish (e.g., crab, lobster, or shrimp), tree nuts (e.g., almonds, pecans, or walnuts), wheat, peanuts, and soybeans.
  2. A food ingredient that contains protein derived from a food specified in paragraph (1), except the following:
    1. Any highly refined oil derived from a food specified in paragraph (1) and any ingredient derived from such highly refined oil.
    2. A food ingredient that is exempt under paragraph (6) or (7) of section 403(w).”

Importantly, unrefined, “gourmet,” “aromatic,” or cold-pressed oils may still contain proteins that cause allergy. They can also be referred to as “crude” oils. The use of these specialty oils is limited; however, it should be recognized that not all available peanut oil is highly refined. If an allergic individual is unsure as to whether a product contains or was fried in highly refined peanut oil, that individual should ask the manufacturer or restaurant for clarification.

What is the cause of food allergies?

  • The true prevalence of food allergies is unknown but estimated to be up to 8% in children.
  • About 90% of food allergy reactions are caused by tree nuts (almonds, walnuts, pecans, cashews, pistachios, etc.), peanuts, milk, eggs, fish, shellfish, wheat, and soy.

Can you be allergic to peanuts but not peanut butter?

No. Allergic reactions are caused by the specific proteins found in peanuts, which are present in both forms.

It seems like more people have peanut allergies, why?

Are all peanut allergies severe?

  • No, some are mild; however, in those who have severe reactions, ingesting just a trace amount can cause a reaction. Food allergy reactions can be unpredictable.
  • It is critical to manage peanut allergies, as with any allergy, to avoid severe reactions, such as anaphylaxis.

What is the allergen in peanuts?

  • The major proteins Ara h 1, Ara h 2, and Ara h 3 are the allergens in peanuts, but at least 7 proteins have been identified as potential allergens.
  • Smelling the aroma of peanuts cannot cause an allergic reaction.

What about peanut oil?

  • Highly refined peanut oil is different from peanuts and from “crude” or gourmet peanut oil because it does not contain peanut allergens.
  • Highly refined peanut oil is purified, refined, bleached, and deodorized, which removes the allergic proteins from the oil.
  • The majority of peanut oil used by foodservice has been highly refined and processed.
  • The FDA does not require highly refined peanut to carry a food allergen.

Can I have an allergic reaction to smelling peanuts?

Smelling the aroma of peanuts cannot cause an allergic reaction.

For the latest research and information on managing peanut allergies, please visit peanutallergyfacts.org.

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