Don’t be fooled. Eggs aren’t just a childhood allergy. Occasionally the allergy will carry over into adulthood. That morning omelet may be causing hives, swelling, upset stomach, or a stuffy or runny nose. “The average age of adults [suffering from food allergies] we have found is 31 years old, which I think would surprise many people who typically think of food allergy in children,” says Bryce. Reactions to eggs are rooted in the protein within the entire egg, egg white, or egg yolk. However, if you notice symptoms after eating any part of an egg, avoid eggs entirely.