According to Virant, approximately 50 percent of five-year-olds suffer from allergies. Thirty years ago, he says, this number was a mere 25 percent. Why the increase? One theory blames new construction – our houses are too well built. “Kids are exposed to higher levels of allergens in these new environments than they were years ago, says Virant. In other words, the allergens are trapped inside.

Another hypothesis for this doubling is hygiene. “People have always had the genetics for allergy,” says Virant. “But because years ago we had a lot of infections, like measles and mumps, it’s like our immune system was busy [fighting] that so you didn’t demonstrate the allergy.” Today, some say we’re so well vaccinated that there’s plenty of energy left to react to allergens.