testing an article
Overview
TEST - What Is a Peanut Allergy?
When someone has a peanut allergy, the body's immune system, which normally fights infections, overreacts to proteins in peanuts. If the person drinks or eats a product that contains peanuts, the body thinks these proteins are harmful invaders. The immune system responds by working very hard to fight off the invader. This causes an allergic reaction.
Peanuts aren't actually a true nut; they're a legume (in the same family as peas and lentils). Peanuts are among the most common allergy-causing foods, and they often find their way into things you wouldn't expect. Take chili, for example: It may be thickened with ground peanuts.
Medically reviewed by: Kenneth A. Alexander, MD, PhD and Pamela H. Arn, MD
Date reviewed: April 2026
