The good news is that more than 98 percent of Americans can enjoy peanuts without any issue.* According to the National Institute of Allergy and Infectious Diseases (NIAID) Expert Panel, peanut allergies affect just 0.6 percent of us – and fall behind milk and eggs in children and behind shellfish among adults in prevalence.*

For those with a true food allergy, however, reactions can be unpredictable – from person to person and episode to episode. That’s why they must be taken seriously. If you suspect you or a loved one has a food allergy, it’s important to get a diagnosis from a trained allergist. And if it turns out you have an allergy, work to develop an emergency action plan and be proactive about educating yourself.

Food Allergy 101

  • Eight foods are responsible for 90 percent of food allergic reactions in the U.S.: milk, egg, shellfish, fish, peanuts, tree nuts, soy and wheat.*
  • According to NIAID, four percent of adults and five percent of children ages 5-17 in the U.S. have food allergies.**
  • Anyone can develop a food allergy during their lifetime.
  • You should always consult an allergist if you have concern about a food allergy. Working with an allergist who is familiar with your health history would assist in managing a food allergy risk.


Can you have a delayed reaction to peanuts?

Some foods can cause delayed reaction. This most often happens in infants who have Food Protein-Induced Enterocolitis Syndrome (FPIES), sometimes referred to as a delayed food allergy. According to the American Academy of Allergy, Asthma and Immunology website, “FPIES is a severe condition causing vomiting and diarrhea. In some cases, symptoms can progress to dehydration and shock brought on by low blood pressure and poor blood circulation.”1

Delayed reactions to peanuts are uncommon but they can occur in rare instances. In fact, delayed reactions caused by FPIES can happen to any food and usually don’t start until hours after a food is eaten.  “FPIES allergic reactions are triggered by ingesting a particular food. Although any food can be a trigger, the most common culprits include milk, soy, and grains.”1 Visit AAAAI website to learn more about FPIES here.

In addition to delayed food reactions, there are also immunoglobulin E

(IgE) mediated reactions. If you have an allergy, your immune system overreacts to an allergen by producing antibodies called Immunoglobulin E (IgE).2 For the approximately 1% of people with a peanut allergy, reactions can be serious and potentially life-threatening. Preventing accidental ingestion and avoiding reactions requires consistent and ongoing management. When an individual with IgE mediated food allergy accidentally eats a food that contains their offending allergen (e.g. peanut), a reaction will usually happen within minutes, but can take up to 2 hours.

Anaphylaxis often begins within minutes after a person eats a problem food. Less commonly, symptoms may begin hours later. Up to 20 percent of patients have a second wave of symptoms hours or even days after their initial symptoms have subsided. This is called biphasic anaphylaxis.3

If you have a peanut allergy, your body will work double-time to protect itself from the protein in peanuts that will cause an immune reaction in your body. This is what happens when you have an allergic reaction. The symptoms that occur when your body is in “attack mode” can range from hives to nausea and facial swelling to anaphylaxis. The range of these symptoms can be from mild to life threatening.4 It is important to note that a delayed biphasic reaction seem to be tied to the severity of the initial anaphylactic reaction.5

If you have a peanut allergy, make sure you are always prepared for a reaction by keeping your epinephrine near you at all times. This medication can reverse the symptoms of an anaphylactic reaction, but you have to use it quickly for it to be effective. Any time epinephrine is used, it is important to seek emergency medical attention in case a second round (biphasic) reaction happens, which may require more intensive medical intervention.

You should always consult a board-certified allergist if you have concern about a food allergy. Working with an allergist who is familiar with your health history will assist in managing a food allergy risk.




  1. Moore, A. M. (2020, September 28). Food Protein-Induced Enterocolitis Syndrome: AAAAI. American Academy of Allergy, Asthma & Immunology.
  2. (n.d.). IMMUNOGLOBULIN E (IGE) DEFINITION. AAAAI. American Academy of Allergy, Asthma & Immunology.
  3. Kemp SF. (2008). The post-anaphylaxis dilemma: How long is long enough to observe a patient after resolution of symptoms?
  4. Types of allergies: Food allergy. (n.d.).
  5. Alqurashi W, et al. (2015). Epidemiology and clinical predictors of biphasic reactions in children with anaphylaxis. DOI:10.1016/j.anai.2015.05.013



What’s with all the peanut allergies?

Though it’s increasingly in the national discourse, the fact is less than 1% of Americans have a peanut allergy,* and food allergies only affect about 5% of children and 4% of teens and adults.** Peanut allergies are not the most common, but they are among the top eight food allergens, and reactions to food allergens can be serious and sometimes life-threatening.

*Prevalence of Peanut and Tree Nut Allergy in the US Determined by a Random Digit Dial Telephone Survey. J Allergy Clin Immunol. 1999 APR;103(4):559-62.
** WAO. White Book on Allergy.
Available at

What causes food allergies?

Researchers believe that food allergies are on the rise, but no one knows what causes food allergies in some people and not in others. While several hypotheses are being investigated, certain conditions in infants, including severe eczema and egg allergy, are known to be risk factors for developing a peanut allergy.* Vaccines are not considered a cause of peanut allergy, and the Center for Disease Control and Prevention clearly states that peanut oil is not used in vaccines.**


* NIAID. Guidelines for the Diagnosis and Management of Food Allergies in the U.S. Available at
** CDC. Available at

Can peanut allergy be prevented?

Yes. Research shows that introducing peanut foods to infants reduces their likelihood of developing peanut allergies.* Guidelines from the National Institute of Allergy and Infectious Diseases recommends that parents introduce infant-appropriate peanut foods starting as early as 4-6 months, depending on their risk for developing peanut allergy.** Discuss questions about food allergies and introducing peanut foods with your pediatrician or healthcare provider.

*NEJM. Randomized trial of peanut consumption in infants at risk for peanut allergy. Available at
** NIAID. 2017 Addendum Guidelines for the Prevention of Peanut Allergy in the United States. Available at

Should pregnant and breastfeeding women avoid peanut foods?

No. The American Academy of Pediatrics explicitly states that research does not support avoiding any food as a means of preventing food allergies. They also state that there’s no need for women to avoid peanuts while pregnant or breastfeeding, unless they are allergic.*

How are peanut allergies diagnosed?

Diagnosing a food allergy is complex, and should be conducted by a board-certified allergist. Blood and skin-prick tests are valuable tools for identifying an allergy, but are not conclusive in diagnosing food allergies on their own. Oral food challenges are the gold standard for food allergy diagnosis.*

*NIAID. Guidelines for the Diagnosis and Management of Food Allergies in the U.S. Available at

How can peanut allergic individuals prevent a reaction?

Avoiding a food allergen is the only way for allergic individuals to prevent a reaction.* Those who are food allergic should always check labels on packaged foods, ask about ingredients in meals at restaurants, and have an emergency action plan in place in case of accidental exposure.

What are the signs and symptoms of an allergic reaction to food?

Identifying and treating a reaction quickly is paramount for safety. Common signs and symptoms of food allergy reaction include:*
– hives
– itching and swelling of the mouth, throat and eyes
– vomiting and diarrhea
– difficulty breathing
– reduced blood pressure, weakness, and fainting

What is the treatment for someone who is suffering from an allergic reaction?

Anaphylaxis is a life-threatening allergic reaction, and can occur when only a small amount of the allergenic protein is eaten. Epinephrine is the approved treatment for anaphylaxis and should be administered without delay.* Individuals should seek medical help when a reaction occurs, including calling 911 anytime epinephrine is administered.

Will smelling or touching peanuts or peanut butter cause anaphylaxis?

No. Research does not support skin contact or airborne peanut butter exposure as a source of anaphylaxis, though hay fever type reactions may occur.* Most instances of anaphylaxis are the result of accidental ingestion of peanut proteins, or exposure through the eyes or mouth.

*JACI. Simonte, S, et al. Relevance of casual contact with peanut butter in children with peanut allergy

How can peanut proteins be cleaned from surfaces and skin?

Common household cleaners have been demonstrated to be effective in removing peanut proteins from surfaces and eating areas. Soap and water remove peanut proteins from skin, but sanitizer alone does not.*

*JACI. Perry, Tamara T., et al. Distribution of peanut allergen in the environment

Do bans on peanut products reduce the risk of accidental exposure?

No. To the contrary, research has shown that banning peanuts in schools may increase the risk for reactions and does not reduce the frequency of epinephrine use.*,** Bans give a false sense of security, and are not recommended by healthcare professionals. Best practices for managing food allergies in foodservice include using basic food safety techniques, separating allergens, clearly labeling allergens and avoiding cross contact in kitchens and serving areas. Most importantly, allergic customers should use caution when dining out, be sure to notify staff of their allergy and be prepared in case of accidental ingestion.

* AACI. Accidental exposure (AE) to peanut in a large cohort of Canadian children with peanut allergy. Available at
** JACI. Impact of School Peanut-Free Policies on Epinephrine Administration. Available at

It seems like peanut allergies are more common than they used to be. Is that the case?

From 1997 to 2007, the prevalence of all reported food allergies has increased by 18 percent among children, according to Food Allergy Research & Education (FARE). A FARE-funded study found the number of children in the U.S. with peanut allergy more than tripled between 1997 and 2008. No one knows the real reason why, but scientists have a variety of theories.