A food allergy is when your child's body has a bad immune reaction to a certain food. This is different from a food intolerance, which does not affect the immune system. This is true even though some of the same signs may be present.

Your child's immune system fights off infections and other dangers to keep them healthy. Food allergy occurs when your child's immune system decides that a food is a "danger" to your child's health. The reason this happens isn't clear. Your child's immune system sends out specific immunoglobulin E (or IgE) antibodies. These antibodies react to the food and cause the release of histamine and other chemicals. These chemicals can cause hives, asthma, itching in the mouth, trouble breathing, stomach pains, vomiting, or diarrhea. It doesn't take much of the food to cause a severe reaction in highly allergic children.

Most food allergies are caused by the following foods:

• Milk
• Eggs
• Wheat
• Soy
• Tree nuts
• Peanuts
• Fish
• Shellfish
• Sesame

Eggs, milk, and peanuts are the most common causes of food allergies in children. Many children “outgrow” their allergies. But some food allergies may be lifelong.

Discuss your child's food allergies with their doctor.

Allergic symptoms may start within a few minutes to an hour after eating the food. Each child may have different symptoms. These can include:

• Severe nausea or vomiting.
• Diarrhea.
• Stomach cramps or stomach pain.
• Red, itchy rash (hives).
• Face swelling.
• Eczema.
• Itching or swelling of the lips, tongue, or mouth.
• Throat itching or tightness.
• Dizziness, with lowered blood pressure.
• Asthma symptoms, such as coughing, runny or stuffy nose, wheezing, or trouble breathing.
• A feeling of impending doom.

It doesn't take much of the food to cause a very bad reaction in highly allergic children. In fact, a tiny piece of a peanut or a small sip of milk can cause a severe reaction in a child who is highly allergic.

Some babies may have non-life-threatening, delayed allergies to milk, soy, or other allergens. These symptoms often are not like the symptoms of other allergies. Instead they may include:

• Colic or fussy behavior.
• Blood in your child's stool.
• Poor growth.
• Severe eczema that doesn't go away.

These non-life-threatening allergies may look like other health problems. They are often hard to diagnose with allergy testing. Make sure your child sees their doctor for a diagnosis.

Anaphylaxis is a severe allergic reaction. It is life-threatening. Symptoms can include:

• Trouble breathing, shortness of breath, or wheezing.
• Feeling as if the throat is closing.
• Hoarseness or trouble talking.
• Swelling of the face, lips, tongue, and throat.
• Cool, moist, or pale blue skin.
• Feeling faint, lightheaded, or confused.
• Nausea, vomiting, or diarrhea.
• Fast and weak heartbeat.
• Feeling dizzy, with a sudden drop in blood pressure.
• Loss of consciousness.
• Seizure.

Anaphylaxis is a medical emergency. If you think your child is having anaphylaxis, call 911 to get help right away. If your child has epinephrine medicine, such as an autoinjector or nasal spray, use it right away, then call 911. Epinephrine will help stop the symptoms of the allergic reaction. It is lifesaving when used for severe allergic reactions. Your child should always have 2 epinephrine doses with them wherever they go.

Your child's doctor will make the diagnosis based on a physical exam and a thorough health history. This history should include a list of foods that were eaten before the allergic symptoms.

The doctor will do some tests to make an exact diagnosis. These tests may include the following.

Skin prick tests are the most common allergy tests. Skin tests measure if there are IgE antibodies to specific allergens, such as foods, pollens, or animal dander. A small amount of diluted allergen is put on the skin. The area is pricked or scratched. If a child is allergic to the allergen, a small, raised bump that looks like a mosquito bite appears after about 15 minutes. Testing for many allergens may be done at the same time. Skin test results are available right away after the testing is done. Skin prick testing may not be done if your child very recently had a severe reaction, or if they have long-term (chronic) hives or severe eczema.

Blood tests for allergies measure IgE antibodies to specific allergens in the blood. The blood test that is most often used is called RAST (radioallergosorbent test). Blood tests may be used when skin tests can't be done or if there are still questions about a food allergy after the skin test. A positive blood test doesn't always mean that your child has a specific allergy. Any positive blood test needs to be explained by a doctor who is familiar with the tests and knows your child's health history. These tests take longer to get results. They may cost more than other allergy tests.

Note: Neither a skin nor a blood test can determine how severe an allergic reaction will be.

This test is given by an allergist. An allergist is a doctor who diagnoses and treats allergies. They give your child a very small amount of an allergen by mouth. The allergen can also be inhaled. Then your child is watched closely for any reaction. If there is no reaction, typically the amount of food will be increased little by little until your child eats a serving of the food. Your child will be continuously watched for reactions. Food challenges are most often done if the allergist thinks your child will be able to eat a food again without a reaction.

There is currently no cure for food allergy in children. It's very important that your child not eat the foods they are allergic to or other similar foods in that food group. If you are breastfeeding your child, talk to your child's allergist about whether or not you need to stay away from these foods too.

It may be important to give vitamins to your child if they can't eat certain foods. Discuss this with your child's doctor.

A medicine called omalizumab is available to help reduce a child's allergic reaction to food if they are accidentally exposed. It may be helpful for several different types of food allergies. This medicine is a monoclonal antibody that is given as an injection. It is approved for children over 1 year old. Children who take this medicine should still avoid the foods they are allergic to. Talk to your child's doctor to see if this medicine is an option for your child.

Children with food allergies who are at risk of a severe reaction (anaphylaxis) should carry 2 epinephrine doses at all times. This medicine helps stop the symptoms of severe reactions. Your child's doctor can teach you how to use it. Make sure those close to your child, such as teachers, care providers, and family members, know how to use it.

Some children may outgrow their allergies. Your child's doctor will discuss follow-up testing or food challenges with you. Many allergies may be short-term in children. Your child may be able to eat the food after age 3 or 4. Reintroduce a food only after discussing it with your child's doctor. This is because of the risk of a severe reaction.

If your baby is allergic to milk, treatment may include changing your baby's formula to a soy formula. If your child has problems with soy formula, your child's doctor might suggest an easily digested hypoallergenic formula.

For many years, it was advised to delay giving a child certain highly allergenic foods until after they were 1 year old. But new research shows that for babies at high risk of developing peanut allergy, giving them peanuts between 4 to 6 months can greatly lower the risk for peanut allergy.

Babies are considered "high risk" if they have moderate to severe eczema or egg allergy. Other children who may be at risk include children with food allergies other than egg allergy and those with siblings with peanut allergy. But these lower-risk babies were not included in the recent studies.

If your child is at high risk for peanut allergy, talk with your child's doctor before giving them peanuts. A blood test or skin test for peanut allergy may be advised first.

If your child does not have eczema or other food allergies, you can introduce peanuts at a time that is developmentally appropriate. Talk to your child's doctor if you have questions.

There is no evidence that breastfeeding or formula feeding gives more protection against food allergies. If you are breastfeeding, you don't need to stay away from any certain foods unless your doctor tells you to. Give your baby only infant formula or breast milk until age 1. Don't give your baby whole milk until after age 1.

Giving your baby eggs early may help prevent egg allergy. Giving other foods early isn't helpful to prevent allergies. But adding foods to a baby's diet within the first year of life is important.

Living with food allergies means not giving your child foods that they are allergic to. For some children, simply touching the allergen can give them an allergic reaction. Families can remove the allergen from their home, but dining out can be challenging.

Here are some tips for dealing with your child's food allergies when you are eating away from home:

• Know what ingredients are in the foods at the restaurant where you plan to eat. When possible, get a menu from the restaurant ahead of time and review the menu items.
• Never assume you know the ingredients in an item. Always ask, even if you have been to the restaurant many times before.
• Let your server know from the start about your child's food allergy. Ask how the dish is prepared and what's in it before you order. If your server doesn't know this information or seems unsure of it, ask to speak to the manager or the chef.
• Don't use buffet-style or family-style service. There may be cross-contamination of foods from using the same serving utensils for different dishes.
• Don't let your child eat fried foods. The same oil may be used to fry several different foods.

Another tip for dining out is to carry a food allergy card. You can give it to your server or the manager before you order food for your child. A food allergy card contains information about the specific items your child is allergic to. It also has additional information such as a reminder to make sure all utensils and equipment used to prepare the meal are thoroughly cleaned before use. You can easily print these cards yourself using a computer and printer.

If your child is eating out with friends and you are not going to be present, give your child a food allergy card (or make sure the adult in charge has one) to give to the server.

Discuss your child's food allergy with their school. Using some of the above strategies at school can be helpful. You may be surprised by how many children at your school have the same or similar allergies.

Your child's epinephrine medicine should always be with them. Do your best to stay away from the foods that cause the allergy, but always be prepared in case of an accidental exposure or reaction.

Ask your child's doctor for an anaphylaxis action plan that outlines the symptoms to look for and the steps to take in case of a severe allergic reaction.

Educate appropriate people at your child's school. Share the anaphylaxis action plan and make certain there are 2 epinephrine doses and designated administrators. Provide full information about the allergy. Update information at the start of each school year and as treatment changes or new information becomes available.

• A food allergy is when your child's body has a bad immune reaction to a certain food.
• Most allergies are caused by milk, eggs, wheat, soy, tree nuts, peanuts, fish, shellfish, and sesame.
• Symptoms of food allergies may include vomiting, diarrhea, cramps, hives, swelling, eczema, itching, trouble breathing, wheezing, and lowered blood pressure.
• Symptoms of milk or soy intolerance may include colic, blood in your child's stool, and poor growth.
• Medicine may reduce the risk of allergic reaction in certain children with a food allergy. But your child should stay away from the foods that cause the symptoms. Your child also needs a food allergy treatment plan and epinephrine medicine, such as epinephrine autoinjectors or nasal spray in case of a severe allergic reaction.
• Educate appropriate school personnel about your child's anaphylaxis action plan and make certain the school has 2 epinephrine doses and designated staff to administer the medicine.

Tips to help you get the most from a visit to your child's doctor:

• Know the reason for the visit and what you want to happen.
• Before your visit, write down questions you want answered.
• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions the doctor gives you for your child.
• Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are and when they should be reported.
• Ask if your child's condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if your child does not take the medicine or have the test or procedure.
• If your child has a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your child's doctor after office hours, and on weekends and holidays. This is important if your child becomes ill and you have questions or need advice.