While other kinds of food allergies present in the first two or three years of life, pollen allergies that contribute to oral allergy syndrome develop more slowly, Wood said, peaking in the teenage and young adult years.

CNN: Oral allergy syndrome may explain mysterious reactions

Studies have shown that some people who undergo allergy shots for pollen allergies will experience relief in oral allergy syndrome, Wood said, but at this point no one should get shots just for that reason, since they don't work on most people's food allergies.

CNN: Oral allergy syndrome may explain mysterious reactions