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The root of the problem
Allergic symptoms like sneezing, watery eyes and a runny nose occur when our immune systems overreact and fi ght something that’s not usually harmful, like particles of dust or pollen. The reasons for the hypersensitivity aren’t clear, but genetics seem to play a signifi cant role. “Around 20 percent of the population has allergies, but if one parent has it, the child’s chances are 45 to 50 percent, and if it’s both parents, it’s about 70 to 75 percent,” Blaiss says. Then there are environmental factors. “All children are born with a predisposition to become allergic, and early in infancy or childhood—depending on their genetic makeup and environmental exposures—they may not switch off this tendency, and may start manifesting allergy symptoms,” says James L. Sublett, M.D., clinical professor and section chief of pediatric allergy at the University of Louisville School of Medicine in Louisville, Ky.

One interesting theory regarding environmental exposure is called the “hygiene hypothesis,” which suggests that parents’ early efforts to keep children’s environments germ-free may actually backfire because a lack of dirt and certain infections may lead to a hypersensitive immune system later on. Indeed, several studies have found that children who attend daycare, or who live on farms or with pets—and the list goes on—tend to develop fewer allergies than children living in, well, more sanitary conditions. Then again, early exposure to certain viruses—like rhinovirus and RSV (respiratory syncytial virus)—may increase the risk of developing allergies and asthma, Blaiss points out. In a nutshell: Our immune systems can be confounding and downright unpredictable.