If you’ve ever reacted badly to a food, you might think you’re allergic. But true food allergies are not all that common. Only about 1 percent of adults and 5 percent of children have them, reports the Mayo Clinic. Most of the time, people actually have a food intolerance.

That’s an important distinction. Food allergies develop when your immune system thinks a food is harmful, and releases chemicals to protect you. These chemicals, in turn, cause allergic symptoms the next time you eat that food.

Also keep in mind, lactose intolerance develops when the body lacks an enzyme needed to digest milk. Food intolerances rarely cause the extreme reactions of food allergies.

The most severe reaction is called anaphylaxis, which causes the throat to swell and block breathing. Some people go into shock and lose consciousness.

The first step in diagnosing a food allergy is to bring symptoms to your doctor’s attention. The most common include: hives or itching; swelling of lips, face, tongue or throat; wheezing, nasal congestion or difficulty breathing; and abdominal pain, diarrhea or nausea.

Your doctor may recommend that you keep a food diary, eliminate problem foods and/or take a skin test.

Common Culprits

Most food allergies result from proteins in:

In children, common food allergies stem from:

Living with a food allergy is as simple as following these precautions: