Scientists do not know what causes a peanut allergy (or any allergy for that matter). Food allergies in general are often inherited.
The Anaphylaxis Campaign1 states that if there is allergy in a family, a sibling of a child with allergies will also be prone to allergies. There is only a seven percent risk of this second child developing peanut allergy, compared with a 1-2 percent risk in a child from a non-allergic family.
Scientists and doctors understand the causes of an allergic reaction to peanuts, or more specifically, an allergic reaction to at least seven of the proteins found in peanuts, and this understanding may lead to treatment advances in the future. Allergic people come into contact with these proteins through one of three general means: direct contact, cross-contact, and through inhalation of airborne particles.
Direct Contact with peanuts
This includes any direct exposure with peanuts, whether by ingestion, through the skin, the lips or any direct manner which puts the body in contact with peanut proteins. Direct contact is not only the most common cause of an allergic reaction, it is also the most preventable, provided the patient is diligent. Keeping children away from popular foods such as peanut butter can be challenging but great-tasting, nutritious peanut butter substitutes are available.
Cross-Contact with peanuts
Cross-contact causes of allergic reactions are somewhat insidious. For example, a company that processes peanuts might use the same machinery to process a non-peanut food product and if the machinery isn't thoroughly cleaned, traces of peanut can get into the other processed foods. Cross-contact is unintentional but for the patient it is not preventable.
Airborne inhalation of peanuts
Some aerosols contain peanuts, for a variety of reasons, along with peanut flour or peanut oil cooking spray. When trace amounts are inhaled by someone with a peanut allergy, they can trigger an allergic response. Like direct contact, inhaling peanut proteins through the air is preventable.
Dive Deeper
References
