Code red! There’s an invader in the body! It’s ... a peanut butter cookie?

Maybe you, or someone you know, has a food allergy. If so, you might already know what’s going on here. The body’s immune system normally attacks harmful invaders like bacteria and viruses. But sometimes, it accidentally sounds the alarm on something harmless, like peanut butter. An army of proteins called antibodies attack, which can lead to a release of chemicals that cause symptoms like sneezing, rashes, wheezing and constricted breathing. Reactions can be mild or life threatening.

Here’s the good news: Food allergies aren’t always forever. They can lessen over time—our immune systems grow up right along with us!

The exact science is a little fuzzy, but exposure to allergens is thought to play a role.

For example, most people outgrow milk or egg allergies naturally, and it usually happens early in life. Allergy experts have found that working little bits of milky or eggy foods into a little one’s diet (such as in baked goods) may help speed up the process. The approach can train the immune system to take it easy on innocent snacking.

Milk and egg allergies are easier to outgrow than others for reasons that aren’t completely clear. A peanut allergy, for example, is much less likely to go away. The lucky ducks who do outgrow it are usually told to keep eating peanuts regularly. Why?

That’s the bad news: Allergies can come back. Regular exposure, scientists think, helps prevent this by making sure peanuts are familiar faces that the immune system won’t mistake for strangers.

So if you’re not allergic to peanuts right now, remember to savor your next Butterfinger!

Thank you to Laura West (MD ’14, Res ’17, ’18, Fel ‘20), an assistant professor of pediatrics at Pitt and an allergist and immunologist at UPMC Children’s Hospital of Pittsburgh, for helping us work through the mystery of allergies.

Read more from the Winter 2024 issue.