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Understanding food allergies

When you sit down to eat, you're probably hoping to end up with a full belly. But if you have a food allergy, you could end up in the hospital.

Symptoms of a food allergy could be as mild as a tingling in your mouth, but some can be life-threatening. According to the American Academy of Allergy, Asthma and Immunology (AAAAI), other symptoms of a food allergy include:

Skin problems, such as hives, a rash, itching and redness.

Breathing problems, such as an asthma attack and swelling of the tongue and throat.

Digestive troubles, including vomiting, diarrhea, cramps, bloating and gas.

Anaphylaxis, which may begin with a warm feeling, flushing, itching in the mouth or a rash. As it progresses, anaphylaxis may cause light-headedness, trouble breathing, severe sneezing, anxiety, stomach cramps, vomiting, diarrhea and a drop in blood pressure. Anaphylaxis can be life-threatening if it isn't treated right away.

Food allergy symptoms usually appear within minutes of eating, though they can sometimes appear a few hours later, according to the AAAAI.

Why allergies?

Food allergies are the result of a problem with the immune system. In people with an allergy, the immune system mistakenly identifies a harmless food as something that is attacking the body. In an attempt to defend the body, the immune system releases chemicals such as histamines and antibodies that end up causing allergy symptoms.

Many different foods can cause a food allergy. But according to Food Allergy Research & Education (FARE), the following eight foods cause most food allergies:

  • Peanuts.
  • Shellfish.
  • Fish.
  • Tree nuts, such as walnuts and pecans.
  • Eggs.
  • Milk.
  • Soy.
  • Wheat.

Allergy or intolerance?

Although many people think they have a food allergy, the problem isn't too common. Still, about 32 million Americans have a food allergy, according to FARE.

In most cases, what people think is a food allergy is really food intolerance. Unlike a food allergy, food intolerance doesn't affect the immune system, says the AAAAI. For example, if a person has cramps or an upset stomach after drinking milk it's often because they are lactose intolerant, not because they are allergic to milk.

To find out if you have a food allergy, you'll need to talk to a doctor. Your doctor may use one or more of the following strategies to diagnose a food allergy:

Skin tests. In these tests, the doctor will put extract from a food into the body through a scratch or prick on the skin. If the skin develops a welt, bump or hive, the test is positive.

Blood tests. In some cases, such as when the person has a serious rash all over the body, skin tests won't work. In these situations a blood test can uncover an allergy.

A food diary. Your doctor may ask you to keep a list of all the foods you eat, when you eat them and any allergy symptoms you have. This can help the doctor figure out which foods you may be allergic to.

Treating food allergies

People who have food allergies can lead an active and full life. The AAAAI suggests these ways to deal with an allergy:

Avoid the food. The best way to treat a food allergy is simply not to eat any of the foods that cause it.

Ask for ingredients. When you go out to eat at a restaurant or another person's house, ask about the contents in any dishes you aren't familiar with. Explain that you have a food allergy and want to make sure the dish is safe for you to eat.

Read labels. Learn to read food labels. Eight major food allergens are required by law to be listed in plain language on food labels. They are milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat and soybeans.

Be ready. Since an allergic reaction could be deadly, it's best to be prepared. If your doctor has prescribed a medicine such as epinephrine or antihistamine, carry it with you at all times. It's also a good idea to wear an identification bracelet that describes your allergy in case you become unable to speak.

If you have an anaphylactic reaction to a food, use your epinephrine injector as directed and get to the emergency room immediately, even if the symptoms start to go away. Acting fast could save your life.

reviewed 4/26/2019

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