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Food Allergy

What is a food allergy?

A food allergy is an immune system reaction to a food. A food allergen is an ingredient or chemical in a food that causes your immune system to react. Allergic reactions happen when your immune system fights too strongly against an allergen and causes you to get sick. Allergic reactions can happen within minutes to several hours after you eat, touch, or smell a food you are allergic to. Reactions can range from mild to life-threatening.

What increases my risk for a food allergy?

A food allergy can develop at any time. Many children outgrow their allergies to milk, wheat, and egg by late childhood. Food allergies that develop in adults often do not go away. Food allergies often begin in children aged 2 years or younger, more commonly in boys. The risk is also greater if a close family member has a food allergy. You are more likely to have food allergies if you also have eczema, hay fever, or asthma.

What are the most common food allergies?

  • Nuts

  • Eggs

  • Fish and shellfish

  • Fruits and vegetables

  • Milk

  • Soy

  • Wheat

What are the signs and symptoms of a mild or moderate allergic reaction to food?

  • Itchy mouth

  • Skin rash and hives

  • Swollen lips and tongue

  • Upset stomach, vomiting, stomach cramps, and diarrhea

What are the signs and symptoms of a life-threatening allergic reaction to food?

A life-threatening reaction is called anaphylaxis. If you have a nut or seafood allergy and asthma, you are at a higher risk of anaphylaxis. A reaction will most likely occur immediately after you eat, touch, or smell a food. You can also have a second reaction up to 8 hours later. Anaphylaxis may begin with signs and symptoms of a mild reaction and quickly turn life-threatening. The following are the most common signs and symptoms:

  • Swelling in your throat that makes it hard for you to swallow and breathe

  • Wheezing and shortness of breath

  • Chest pain or tightness

  • Dizziness and a very fast heartbeat

How are food allergies diagnosed?

Your healthcare provider will ask about your symptoms after you eat, touch, or smell certain foods. He will ask how long it takes for symptoms to appear and how long they last. He will also ask about the amount of food that triggers symptoms. He will check your skin, nose, and ears, and listen to your breathing. You may need to keep a food diary to write down everything you eat and any symptoms you develop. You may also need the following:

  • A skin prick test is used to check for an allergy to certain foods. Your healthcare provider will scratch tiny bits of different foods under your skin. If a bump appears within a few minutes, you likely have an allergy to that food.

  • Blood tests may be used to find antibodies that lead to food allergies. An antibody is part of your immune system.

  • An elimination diet is used to help you avoid a food for several weeks to see if your symptoms get better.

  • Food challenge means you eat small amounts of foods that you may be allergic to. A healthcare provider stays with you to watch for and treat any allergic reactions.

What medicine is used to treat a mild or moderate food allergy?

Your healthcare provider may tell you take an antihistamine if you think you are having an allergic reaction. This medicine can help treat symptoms such as itching and rashes.

What medicine is used to treat anaphylaxis?

Your healthcare provider will give you an anaphylaxis kit and a written plan that tells you what to do. The kit contains medicine called epinephrine that helps stop the reaction. Check the expiration date on the kit every month and replace it before it expires.

  • Give a shot of epinephrine immediately and call 911. Give the shot into a muscle, such as the thigh. Your healthcare provider can show you how to give the shot. Do not try to drive yourself to a hospital.

  • Keep 2 shots of epinephrine with you at all times. You may need a second shot, because the emergency medicine only works for about 20 minutes and symptoms may return.

How can I prevent an allergic reaction?

  • Do not eat the food that causes your allergy. Even a small taste can cause an allergic reaction. Your healthcare provider or a dietitian can help you plan a balanced diet. Babies may need to drink a formula that does not contain milk or soy.

  • Carry medical alert identification. Carry a card or wear jewelry that says you have an anaphylaxis kit for allergies. Medical alert identification tells people how to help if you have a reaction.

  • Create an action plan with treatment instructions. Your healthcare provider can help you create a written plan that explains the allergy and an emergency plan that explains how to treat a reaction. Give copies of the action plan and emergency instructions to family members, work, daycare providers, or school staff. Show them how to use an anaphylaxis kit. Update the action plan as the allergy changes.

  • Recognize foods you are allergic to. A dietitian can teach you how to read labels for ingredients that cause your allergies.

  • Ask about ingredients in foods prepared outside your home. When you eat out, ask what is in the food you want to order. Ask how food is prepared. Fried foods may contain small amounts of food allergens, such as nuts and shellfish.

  • Use good hygiene. Do not share utensils or food. Wash hands before and after meals.

When do I need to follow up with a healthcare provider?

You may need to see specialists, such as an allergist or dietitian, for ongoing care. Your healthcare provider may want to test you regularly to see if the food allergy changes. Write down your questions so you remember to ask them during follow-up visits.

Is the flu vaccine safe for an egg allergy?

Do not get the nasal spray form of the flu vaccine if you have an egg allergy. The nasal spray may contain egg proteins that can cause anaphylaxis. Ask your healthcare provider if the injection form of the vaccine is safe for you.

Call 911 for any of the following signs of anaphylaxis:

  • Swelling in your throat that makes it hard for you to swallow and breathe

  • Wheezing and shortness of breath

  • Chest pain or tightness

  • Dizziness and a very fast heartbeat

When should I seek immediate care?

  • Your mouth, tongue, or throat swells.

  • You have itching or hives that spread all over your body.

When should I contact my healthcare provider?

  • You have new or worsening rashes, hives, or itching.

  • You have an upset stomach or are vomiting.

  • You have stomach cramps or diarrhea.

  • You have questions or concerns about your condition or care.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

© 2014 Truven Health Analytics Inc. Information is for End User's use only and may not be sold, redistributed or otherwise used for commercial purposes. All illustrations and images included in CareNotes® are the copyrighted property of A.D.A.M., Inc. or Truven Health Analytics.

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