Practice Consideration
The primary treatment for peanut allergy is the strict avoidance of peanuts in all forms. The approach to managing peanut allergies requires more than simply avoiding visible peanuts or peanut-containing products.
Heat Stability of Peanut Protein
Peanut protein is not heat-labile, meaning cooking does not denature the allergenic protein. Therefore, both raw and cooked peanuts pose a risk and must be completely avoided.
Trace Exposure Risk
Even trace amounts of peanut protein can trigger allergic reactions, including life-threatening anaphylaxis. These reactions are most commonly caused by direct oral ingestion but can also occur through inhalation of aerosolized peanut protein. Note: Inhalation reactions are more common with fin fish, shellfish, or milk allergies. Topical exposure to peanuts is rarely associated with systemic reactions.
Importantly, the severity of previous allergic reactions does not predict future reactions, meaning even a mild past reaction could lead to a severe response in the future.
Associated Allergies and Label Reading
Individuals with peanut allergies may experience reactions to other legumes and tree nuts, such as green peas, soy, lupine (or lupin) and other tree nuts. Lupine is commonly found in European foods and gluten-free flour substitutes in the U.S. Label reading is advised to avoid accidental exposure to these allergens. Consultation with an allergist is recommended to determine if avoidance is necessary, as eliminating certain foods can impact nutrition, quality of life, and potentially increase the risk of developing new food allergies.
Cross-sensitivity and Cross-reactivity
- Cross-sensitivity occurs when an individual shows a positive reaction to an allergen in diagnostic tests (e.g., peanuts, lupine, green peas, soy) but can tolerate the allergen without developing clinical symptoms. If tolerated, continued consumption of the allergen is recommended to prevent the development of a true allergy. Such individuals are often described as "sensitized but not clinically reactive."
- Cross-reactivity arises when similar protein structures are shared between different allergens, causing the immune system to react to both. Notable cross-reactivities include:
- Peanut and lupine
- Walnut and pecan
- Pistachio and cashew
Cross-contact (Cross-contamination) Risk
Cross-contact, also known as cross-contamination, occurs when peanut proteins mix with another food, either through shared utensils, surfaces, or other means. For more detailed guidelines on this topic refer to: Avoiding Cross-Contact. Common sources of peanut and cross-contact risk include:
- Peanut Oil: Cold-pressed, expeller-pressed, or extruded peanut oil contains peanut protein. Refined peanut oil is generally safe for those with peanut allergies; however, it is often not clearly labeled, necessitating verification before consumption.
- Baked goods and sweets: Candy, cookies, bread, crackers, pastries, cakes and ice creams may contain or come into contact with peanuts.
- Shared food preparation spaces such as kitchens, including shared commissary kitchens, that handle peanut products pose a significant risk. (More discussed on this topic in Minimizing Food Allergen Exposure Risk Outside the Home)
- Tree nut: Cross-contact is only a risk if there is an additional allergy (e.g. treenut/walnut etc.). Note, it is possible to find treenuts in facilities that do not handle peanuts
High-Risk Cuisines
Certain cuisines, including Italian, Asian, and African foods, carry a heightened risk of peanut exposure due to the common use of peanut ingredients or cross-contact with peanut-contaminated utensils and surfaces.
- Italian-style foods: pesto may be made with any nut
- Asian-style foods (Chinese, Japanese, Korean, Thai, Vietnamese, Indian use peanut oil extensively)
- African foods: Rice with peanuts
Non-food sources of peanuts: (not exhaustive)
Peanuts may be present in non-food items, such as:
- Animal litter, animal feed or pet food, pet toys,
- Beauty products: ensure ingredients in toothpaste, body wash, shampoo, sunscreens etc.. do not contain peanut in any of the forms, including oils. Read about a 2019 food allergy fatality to milk found in toothpaste here.
- Some medications or supplements (vitamins, minerals, “teas”, protein powders – this is a big cross-contact risk)
- Craft materials or food materials used in classroom projects
- Potting soil
- Peanut shells, walnut shells, and mollusk shells are sometimes used to sandblast engines in auto shops.
Note: Despite common misconceptions, peanuts are not botanically nuts, but rather legumes.
Conclusion
Strict avoidance of peanuts and careful management of cross-contact risks are crucial for individuals with peanut allergies. Regular consultation with an allergist is recommended to monitor potential associated allergies and ensure a balanced approach to dietary restrictions that preserves nutrition and quality of life.
References
- Francis OL, Wang KY, Kim EH, Moran TP. Common food allergens and cross-reactivity. J Food Allergy. 2020 Sep 1;2(1):17-21. doi: 10.2500/jfa.2020.2.200020. PMID: 39022146; PMCID: PMC11250430.
- Peanut Allergy, Living with Food Allergies, Common Allergens, FARE (Food Allergy Research & Education). Accessed 7 September 2024. Available at: https://www.foodallergy.org/living-food-allergies/food-allergy-essentials/common-allergens/peanut
- Peanut Allergy, Living with Food Allergies, Food Allegens, Kids with Food Allergies. Accessed 7 September 2024. Available at: https://kidswithfoodallergies.org/living-with-food-allergies/top-food-allergens/peanut-allergy/
- Avoiding Cross-Contact,Living with Food Allergies, Resources: FARE (Food Allergy Research & Education). Accessed 7 September 2024. Available at: https://www.foodallergy.org/resources/avoiding-cross-contact
- How to Prevent Cross-Contact and Accidental Environmental Exposure. Cross Contact. FAACT (Food Allergy and Anaphylaxis). Accessesd 7 September 2024. Available at https://www.foodallergyawareness.org/food-allergy-and-anaphylaxis/cross-contact/cross-contact