This theory "contends that immune systems become over-reactive in very clean environments, [like those] associated with the medicine and hygiene practices [used today]," says Dr. Bill Parker, assistant professor at Duke University Medical Center, and advocate of the hygiene hypothesis.
In these super-clean environments, he says, "the immune system essentially lacks a normal workload... however, [it] does what it is built to do, and finds something to attack, often directing its attention toward such harmless things as pollen grains ... even healthy food."
But whether it's exposure to certain foods too early or exposure to germs too late, once a child has an allergy, "the number one treatment is education [and] preventing reactions," Bassett says.
Treatment for the allergy itself may be possible "in the not too distant future" he notes, but for now, it is crucial for parents and children to ask questions, plan ahead, and be what he calls a "label detective", making sure that allergens are not hiding out in processed foods.
"Every year there are [more than a] hundred deaths attributable to food allergy, and a lot of near deaths," he says.
"People need to take it seriously."