Allergies Versus Parasites
The human body is not a perfect machine but the allergic fit it can produce in the face of something that should be harmless, like tree pollen, does serve a purpose. "It's acting very much like there's a parasite that you're trying to get rid of," says White. "The body essentially views normal things in the environment the same way it would a parasite." In other words, the symptoms we recognize as allergies are side effects of the body's attempt to get the proper immune cells to the site of the invader, the allergen that it has mistaken for a harmful parasite.