Your study, the most comprehensive on the subject to date, found that about 50 percent of adults with food allergies developed them after age 18. What’s the significance?

This was a new epidemic that kind of crept up. We used to think allergies were something that concerns kids. But all of a sudden, you start hearing more about adults who are developing food allergies. We wanted to put a number to that.

So what’s caused this epidemic?

A lot of what’s being talked about is how our society has changed from a hygiene standpoint. It starts with an increase in C-sections—babies aren’t going through [the birth canal], getting bacteria from their mom. Kids don’t play in the dirt as much. We’re using antibacterial soaps and cleansers. We’re not picking up the bugs we used to pick up, so our immune system is not being stimulated. We need those bacteria, at least the good ones.

For pollen, you can just pop a pill. But the only treatment for food allergies is avoidance—or epinephrine for a severe reaction. Any hope of that changing?

A couple [of treatments] are in clinical trials. Peanut oral immunotherapy, for example: [Doctors] start at a low dose [of peanut protein] and slowly increase it until you can tolerate a certain amount. The other one is epicutaneous immunotherapy. It’s a patch that sends little bits of peanut protein through the skin so that your immune system gets used to it. They’re both in phase 3 clinical trials [the last stage of testing before hitting the market].

Your daughter has a peanut allergy, right?

Yes, this is very near and dear to my heart. For [affected] families, it’s such a huge cause of fear and anxiety.

I just fed my 7-month-old peanut butter for the first time. He got a little rash around his mouth. Should I freak out?

The American Academy of Pediatrics changed its guidelines this year to recommend introducing peanut products to infants. That’s what you followed, right? I was on that committee. A 2015 study found that if high-risk infants are fed peanut products early, their chance of developing an allergy decreases by 80 percent, which is crazy. If it’s just a little redness, we do encourage continuing. But if you’re nervous, go see an allergist.