Peanut Allergy

Medical Author:

Syed Shahzad Mustafa, MD

Syed Shahzad Mustafa, MD


After growing up in the Rochester area, Dr. Mustafa pursued his undergraduate studies at the Johns Hopkins University in Baltimore and attended medical school at SUNY Buffalo. He then completed his internal medicine training at the University of Colorado and stayed in Denver to complete his fellowship training in allergy and clinical immunology at the University of Colorado, National Jewish Health, and Children’s Hospital of Denver.


Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR


Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.


Peanut allergy facts

  • The prevalence of peanut allergy in the United States is approximately 1% to 2%.
  • The rate of peanut allergy is higher in individuals with additional allergic conditions or a family history of allergic conditions, including a sibling with peanut allergy.
  • One-third of patients with peanut allergy are also allergic to tree nuts.
  • About 90% of reactions to peanut occur within 20 minutes of exposure.
  • Peanut allergy with asthma is a risk factor for a severe allergic reaction.
  • Peanut allergy symptoms and signs include
  • More severe symptoms and signs include:
  • Epinephrine is the treatment of choice for a systemic allergic reaction to peanut.
  • Roughly 20% of children outgrow peanut allergy by their school-age years.
  • There is no cure for peanut allergy.

What is a peanut allergy?

Peanut allergy develops when the body’s immune system has an abnormal, hypersensitivity response to one or more of the peanut proteins. Peanut allergy is one of the most common food allergies in both children and adults. It receives particular attention because it is relatively common, typically lifelong, and can cause severe allergic reactions. Peanut allergy is the leading cause of anaphylaxis and death due to food allergy. It can lead to significant burden on patients and their families. Peanut is a common food ingredient making strict avoidance difficult. Therefore, there is a relatively high rate of accidental peanut ingestions for those trying to avoid peanuts. For all of the above reasons, peanut allergy has become an important public-health issue.

How common is a peanut allergy?

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This prevalence of peanut allergy has increased significantly over the past decade, most notably in westernized countries. The prevalence of peanut allergy in westernized countries is approximately 1% to 2%, with the greatest prevalence in children under 3 years of age. This increase in prevalence has also occurred with other allergic conditions, such as eczema (atopic dermatitis), asthma, and hay fever (allergic rhinitis). Peanut allergy is much less common in underdeveloped areas of the world, such as Africa and Asia. Emerging literature suggests that the increasing rate of peanut allergy may be leveling off in many nations, including the United States.

Why is peanut allergy increasing and what are risk factors for a peanut allergy?

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It is not clear why the rate of peanut allergy is increasing in the United States and other westernized nations. This is an area of active medical research. Risk factors for peanut allergy include a personal or family history of allergic conditions, such as asthma, hay fever (allergic rhinitis), and particularly eczema (atopic dermatitis). A sibling of a child with peanut allergy has approximately a 7% chance of developing peanut allergy, as compared to the baseline population risk of 1% to 2%. Other factors influencing peanut allergy include exposure during pregnancy and lactation, exposure to peanut protein through household dust, and exposure to skin-care products containing crude peanut oil.

There has been significant recent research on the timing of peanut exposure into a child’s diet and its effect on the risk of allergy. In the early 2000s, recommendations were to delay the introduction of peanuts until 3 years of age. The rates of peanut allergy more than doubled in countries following these recommendations. It was also observed that rates of peanut allergy were significantly lower in countries, such as Israel, where children were introduced to peanuts at a younger age. In 2008, the recommendation regarding delayed introduction of peanut was retracted, and research began to indicate that earlier introduction of peanut may be protective against food allergy. In a landmark study publish in 2015 (LEAP study), it was shown that early introduction of peanut into a child’s diet, at 4 months of age, significantly decreased the risk of developing peanut allergy in a high-risk population. This study, along with additional research, may very well lead to updated guidelines on the timing of introduction of peanuts and other highly allergenic foods into a child’s diet.

Medically Reviewed by a Doctor on 11/3/2015


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Peanut Allergy – Symptoms and SignsQuestion: What peanut allergy symptoms and signs did you or a loved one experience?
Peanut Allergy – TreatmentQuestion: What treatment(s) have been effective for your peanut allergy?
Peanut Allergy – Risk FactorsQuestion: Do you have any risk factors for a peanut allergy?
Peanut Allergy – OutgrowQuestion: Did you or your child outgrow peanut allergy?
Peanut Allergy – Family HistoryQuestion: Does peanut allergy run in your family?