What is a food allergy?
A food allergy is when a person’s immune system responds as if a certain food is harmful to the body. If a person eats, touches, or breathes in that food, he or she can have an allergic reaction. Most allergic reactions happen within 5 minutes to 1 hour after eating or touching the food. The most common foods that people are allergic to are:
- Milk and foods that contain milk, such as ice cream or butter (called dairy foods)
- Tree nuts, such as almonds or cashews
- Shellfish, such as shrimp or oysters
People can have an allergy to one or more foods. Sometimes it is hard to tell if you really have a food allergy or not. People can feel sick after eating some foods for other reasons. For example, people can get heartburn after eating spicy foods, or have vomiting and diarrhea from food poisoning. But these are not the same as a food allergy.
What are the symptoms of a food allergy?
The symptoms of a food allergy can range from mild to severe.
Mild symptoms can include:
- Hives – Raised, red patches of skin that are very itchy
- Red or swollen skin
- Itchy, watery, or swollen eyes
- Runny nose or sneezing
Severe symptoms are also called “anaphylaxis.” They can include:
- Swelling of the throat, or coughing a lot
- Wheezing or trouble breathing
- Throwing up or having diarrhea
- Feeling dizzy or passing out
Symptoms can differ from person to person. Also, a person can have different symptoms each time he or she has an allergic reaction.
Is there a test for food allergy?
Yes. Doctors can use 2 types of tests to tell if you have a food allergy. You and your doctor will decide which is best for you.
- Skin test – For a skin test, the doctor will put a drop of the food you might be allergic to on your skin and make a tiny prick in the skin. Then, he or she will watch your skin to see if you get a red, itchy bump, like a mosquito bite.
- Blood test – Blood tests for food allergies look for antibodies (proteins) called “IgEs” that the body makes when it is having an allergic response.
Your doctor or nurse will also do an exam and talk with you. Sometimes it can be hard to figure out what food you are allergic to. Keeping a record of the foods you eat and the symptoms you have is helpful.
Should I see a doctor or nurse?
Yes. If you have severe allergic symptoms.
How is a food allergy reaction treated?
The best treatment for a severe reaction is a medicine called “epinephrine.” At the hospital, doctors can give you epinephrine and other medicines to treat your symptoms. Doctors will also watch to make sure your symptoms don’t get worse.
Your doctor might prescribe a device called an “autoinjector” (for example, the EpiPen). This device has a shot of epinephrine that you can give yourself. If you have an autoinjector, you should keep it with you at all times. Use it right away if you think you are having a severe allergic reaction. After you use the autoinjector, call for an ambulance. That’s because the symptoms might come back and you might need more treatment in the hospital.
If you have mild food allergy symptoms, your doctor might recommend a medicine called an antihistamine. You can get this medicine without a prescription. It can help stop itching and hives.
Can allergic reactions be prevented?
Yes. You can prevent an allergic reaction by not eating the food you are allergic to. Even a tiny bite of food can cause a big reaction. You and your doctor can make a food allergy plan that includes:
- Knowing how to avoid the food you are allergic to by reading food labels
- Telling restaurants about your food allergy if you eat out
- Knowing when to get help for a reaction
- Having an epinephrine autoinjector with you at all times
- Wearing a medical bracelet to let others know about your allergy
What will my life be like?
Most people with a food allergy are able to live normal lives. But you might need to make some changes in your life. You will need to follow your food allergy plan.
You can have food allergies for your whole life. But people sometimes outgrow them. Talk with your doctor about how to tell if you have outgrown a food allergy.
Is there any way to prevent a food allergy?
It’s not clear. If you have a food allergy — or your child does — you might worry that a new baby will have it, too. The baby might be at higher risk of having the same allergy. But that doesn’t mean he or she will definitely have it. He or she might have the same food allergy, a different food allergy, or no food allergy at all.
If you are pregnant or breastfeeding, you might wonder whether you should avoid a certain food. For example, if you already have child with a milk allergy, should you stop drinking milk to reduce your new baby’s risk of allergy? In most cases, the answer is probably not. But you should talk to your doctor to make sure you are eating a healthy diet for your situation.
When your baby is old enough to start eating solids, you will have to decide when to offer the food. Doctors used to think it was better to delay this if a baby was at high risk for allergy. Now, they think it might be better not to wait until the baby is older, and to give the food at the normal time. But there is still no way to know for sure if your baby will have an allergy. Your baby’s doctor can help you decide when and how to offer certain foods.