Peanut allergies don’t begin to cause problems for people the first time they are exposed to peanuts. Rather, the immune system first develops antibodies in reaction to the proteins in peanuts and peanut oil. Thus, the next time the body recognizes these proteins, the antibodies attack them. This induces an allergic reaction.
Scientists can not say for certain why things like peanut proteins induce allergic reactions, nor can they determine why some people develop a peanut allergy and others do not. And while it is impossible to predict with absolute certainty whether a child will develop a peanut allergy, it is at least possible to consider what their chances are of developing one: If one parent suffers from an allergy, the child’s odds of developing an allergy—any allergy—are just under 50%. If both parents do, the odds rise to about 70% likelihood that the child will develop allergies as well.
In short, there seems to be a hereditary predisposition for allergies in some people. The allergy commonly begins at a very young age, and for the majority of them, it is a lifetime condition. In approximately 20-25% of them, however, the allergy resolves itself.
Allergy vs. Intolerance
Peanut allergy is not the same as peanut intolerance. People with peanut intolerance might suffer minor symptoms from ingesting peanuts, such as an upset stomach, but they do not have an allergy to peanuts because their immune system does not engage in the process.
An allergic reaction can be caused by direct contact, cross-contact, and even inhalation.