Food Allergy

Medically reviewed by Drugs.com. Last updated on May 4, 2025.

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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 the food. You can also have a second reaction up to 8 hours later.

DISCHARGE INSTRUCTIONS:

Call your local emergency number (911 in the US) for signs or symptoms of anaphylaxis,

such as trouble breathing, swelling in your mouth or throat, or wheezing. You may also have itching, a rash, hives, or feel like you are going to faint.

Return to the emergency department if:

• Your mouth, tongue, or throat swells.
• You have itching or hives that spread all over your body.

Call your doctor if:

• 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 about your treatment, medicine, or care.

Drugs used to treat this and similar conditions

Treatment options

The following list of medications are related to or used in the treatment of this condition.

• EpiPen
• Dupixent
• triamcinolone
• Auvi-Q
• Xyzal

Medicines:

You may need any of the following:

• Epinephrine is used to treat severe allergic reactions such as anaphylaxis.
• Antihistamines decrease mild symptoms such as itching or a rash.
• Steroids may be given to decrease inflammation.
• Short-acting bronchodilators help open your airways quickly. These medicines relieve sudden, severe symptoms and start to work right away. They may be called rescue inhalers or relievers.
• Take your medicine as directed. Contact your healthcare provider if you think your medicine is not helping or if you have side effects. Tell your provider if you are allergic to any medicine. Keep a list of the medicines, vitamins, and herbs you take. Include the amounts, and when and why you take them. Bring the list or the pill bottles to follow-up visits. Carry your medicine list with you in case of an emergency.

Steps to take for signs or symptoms of anaphylaxis:

• Immediately give 1 shot of epinephrine only into the outer thigh muscle.
• Leave the shot in place as directed. Your provider may recommend you leave it in place for up to 10 seconds before you remove it. This helps make sure all of the epinephrine is delivered.
• Call 911 and go to the emergency department, even if the shot improved symptoms. Do not drive yourself. Bring the used epinephrine shot with you.

Safety precautions to take if you are at risk for anaphylaxis:

• Keep 2 shots of epinephrine with you at all times. You may need a second shot, because epinephrine only works for about 20 minutes and symptoms may return. Your provider can show you and family members how to give the shot. Check the expiration date every month and replace it before it expires.
• Create an action plan. Your provider can help you create a written plan that explains the allergy and an emergency plan to treat a reaction. The plan explains when to give a second epinephrine shot if symptoms return or do not improve after the first. Give copies of the action plan and emergency instructions to family members, work and school staff, and daycare providers. Show them how to give a shot of epinephrine. Update the plan as the allergy changes.
• Do not eat the food that causes your allergy. Even a small taste can cause an allergic reaction. Your 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. A dietitian can teach you how to read labels for ingredients that cause your allergies.
• Carry medical alert identification. Wear jewelry or carry a card that says you have a food allergy. Ask your provider where to get these items.
• 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.
• Be careful when you exercise. If you have had exercise-induced anaphylaxis, do not exercise right after you eat. Stop exercising right away if you start to develop any signs or symptoms of anaphylaxis. You may first feel tired, warm, or have itchy skin. Hives, swelling, and severe breathing problems may develop if you continue to exercise.
• Wash your hands before and after meals. Do not share utensils or food.

Vaccines and egg allergy:

Tell healthcare providers if you have an egg allergy before you receive any vaccine. Some vaccines contain egg protein that can cause an anaphylactic reaction. The flu vaccine is considered safe for a person with an egg allergy. An egg-free vaccine may be available. Your provider will tell you if you should get the egg-free vaccine instead. You may need tests before you can receive certain other vaccines. Your provider can give you more information.

Follow up with your doctor as directed:

You may need to see specialists for ongoing care. Your 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.

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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.

Further information

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