Causes

Peanut allergy occurs when your immune system mistakenly identifies peanut proteins as something harmful. Direct or indirect contact with peanuts causes your immune system to release symptom-causing chemicals into your bloodstream.

Exposure to peanuts can occur in various ways:

• Direct contact. The most common cause of peanut allergy is eating peanuts or peanut-containing foods. Sometimes direct skin contact with peanuts can trigger an allergic reaction.
• Cross-contact. This is the unintended introduction of peanuts into a product. It's generally the result of a food being exposed to peanuts during processing or handling.
• Inhalation. An allergic reaction may occur if you inhale dust or aerosols containing peanuts, from a source such as peanut flour or peanut oil cooking spray.