Ann Wood's* son Daniel almost died when he was 2  -- from a snack. At first, Wood hadn't been worried when she'd called home from work and her babysitter mentioned that Daniel had just thrown up after eating an almond butter sandwich. "These things happen," she'd reassured her babysitter. "Just keep an eye on him." When Wood called back 15 minutes later, though, Daniel had developed diarrhea. When she called a third time, as she rushed home to their New Jersey suburb, he was struggling for breath. "Call 911 right now!" she instructed.

As Daniel emerged from an ambulance at the hospital, his face was covered with large red welts. The paramedics had found him in anaphylactic shock, which meant that his throat was swelling shut and his blood pressure was plummeting toward zero. They brought him back with injections of the stimulant epinephrine and an inflammation-squelching steroid. The next day, Wood and her husband learned that Daniel's reaction was from a life-threatening foodallergy to peanuts, a trace amount of which had likely cross-contaminated the almond butter.

Now in second grade, Daniel isn't the only one of his friends with food allergies. Five kids in his grade carry EpiPens, the prefilled syringes that contain enough epinephrine to reverse a severe allergic reaction. And his grade is hardly unique. In the U.S., about 1 in 12 children under 3 have food allergies, and around 150 die each year because of them. Outside the U.S., the problem is no less serious; the incidence of food allergies in kids around the world has at least doubled over the last decade.

"The increase seems to be part of a general rise in allergies of all kinds," says Scott Sicherer, M.D., a pediatric allergist at New York's Mount Sinai School of Medicine and author of Understanding and Managing Your Child's Food Allergies. While it's not clear what's behind this disturbing trend, many experts think it may have to do with the so-called Hygiene Hypothesis: that modern life  -- with its lack of exposure to the "germiness" of unfiltered water, dirt, and animals  -- can leave people's immune systems prone to overreact to harmless substances. The result: Even something as innocent-seeming as a peanut can cause the body's defenses to go into overdrive. As overactive immune cells release histamine and other inflammatory chemicals, they produce symptoms such as hives, itching, diarrhea, and in severe cases, life-threatening anaphylaxis.

While regular exposure to relatively harmless bacteria might help make us less allergy-prone, no medical expert would advocate going back to the days of rampant cholera and intestinal parasites. So where does that leave us? Fortunately, there are steps you can take to reduce your child's risk of developing food allergies, and ways to handle them if they arise.


Name has been changed

Jessica Snyder Sachs is the author of Good Germs, Bad Germs: Health and Survival in a Bacterial World.