"If it seems like your seasonal allergies are getting worse over time, you're probably not wrong. Estimates are that 30 to 40% of the world's population now have some form of allergy, and medical anthropologist Theresa MacPhail says allergic reactions — including everything from hay fever to eczema and asthma — are growing in the U.S. and around the world.
MacPhail is an associate professor of science and technology studies at Stevens Institute of Technology. In her new book, Allergic: Our Irritated Bodies in a Changing World, she explores some of the theories behind the rise in allergies — including the theory that excessive emphasis on hygiene (and perhaps even showering) can contribute to the development of sensitivities.
"You've probably heard that we don't let kids eat enough dirt. They don't play in enough dirt. They're not around enough germs," she says. "We have seen that people who send their children to daycare centers, there's something about being in a daycare center that is also protective."
Other explanations for the increase in allergic reactions include the shift in our diets over the years toward more processed foods and less fiber, which affects our microbiomes. MacPhail also posits a link between allergies and a rise in exposure to environmental toxins, which could reduce the skin's ability to ward off potential allergens."