According to the Mayo Clinic
Peanut allergy is caused by an immune system malfunction. Your immune system identifies peanuts as harmful triggering the production of immunoglobulin E (IgE) antibodies to neutralize the peanut protein (allergen). The next time you come in contact with peanuts, these IgE antibodies recognize it and signal your immune system to release histamine and other chemicals into your bloodstream.
Histamine and other body chemicals cause a range of allergic signs and symptoms. Histamine is partly responsible for most allergic responses, including runny nose, itchy eyes, dry throat, rashes and hives, nausea, diarrhea, labored breathing and even anaphylactic shock.
Exposure to peanuts can occur in three ways:
* Direct contact. The most common cause of peanut allergy is direct contact with peanuts. This means exposure via all routes of contact — usually through eating peanuts, but including kissing or touching someone who's been in direct contact with peanuts.
* Cross-contact. This is the unintended introduction of peanuts into a product. It's generally the result of exposure to peanuts during processing or handling of a food product.
* Inhalation. An allergic reaction may occur if you inhale dust or aerosols containing peanuts, such as that of peanut flour or peanut oil cooking spray.
Common food products that can trigger peanut allergy symptoms if they contain peanut proteins include:
* Peanut butter
* Peanut flour
* Ground or mixed nuts
* Baked goods, such as cookies and pastries
* Ice cream and frozen desserts
* Energy bars
* Salad dressing
* Cereals and granola
* Grain breads
* Marzipan (a molding confection made of nuts, egg whites and sugar)
* Nougat
Peanuts may be present in not-so-obvious foods including:
* Arachis oil. This is another name for peanut oil. Pure peanut oil usually doesn't trigger allergic reactions because peanut proteins are usually removed during processing. However, peanut oil can become contaminated with peanut proteins.
* Artificial tree nuts. Peanuts can be flavored to taste like other nuts, such as walnuts or pecans.
* Chocolate candies. Some chocolate candies are produced on equipment that is also used for processing peanuts or peanut-containing foods.
* Cultural foods. Some African, Chinese, Indonesian, Mexican, Thai and Vietnamese dishes often contain peanuts or are exposed to peanuts during restaurant preparation.
* Nut butters. Nut butters, such as cashew nut butter, are often processed by the same equipment used to make peanut butter.
* Specialty items. Foods sold in bakeries and ice-cream shops may come in contact with peanuts.
* Sunflower seeds. Many brands of sunflower seeds are processed on equipment also used to produce peanuts.