What is food allergies?

When your child has a food allergy, your child's body thinks that those foods are trying to do harm. It fights back by setting off an allergic reaction. A mild reaction may include a few raised, red, itchy patches of skin (called hives). A severe reaction may cause hives all over, swelling in the throat, trouble breathing, belly pain, nausea or vomiting, diarrhea, or fainting. This is called anaphylaxis (say "ANN-uh-fuh-LAK-suss"). It can be deadly.

A good way to prevent your child's allergic reaction is to avoid the foods that cause it. An allergy doctor or a dietitian may be able to help you understand which foods will be okay and what to avoid. Learn what to do if your child has a reaction.

When you eat a food that triggers an allergic reaction, your body's immune system sees the food as a foreign substance (allergen). Your body reacts by making antibodies against the food. When you eat the food again, the antibodies attack the allergen. They release chemicals that cause the symptoms of an allergic reaction.

Food allergies can cause many different symptoms. They can range from mild to serious. A mild reaction may include tingly lips, a stuffy nose, dizziness, and a few raised, red, itchy patches of skin (called hives).

The most severe reaction is called anaphylaxis (say "ANN-uh-fuh-LAK-suss"). It affects your child's whole body. Anaphylaxis can start within a few minutes to a few hours after your child eats the food. And the symptoms can go away and come back hours later. A severe reaction may cause hives all over, swelling in the throat, trouble breathing, nausea or vomiting, or fainting.

Children usually have the same symptoms as adults. But sometimes a small child just cries a lot, vomits, has diarrhea, or does not grow as expected.

The best treatment for allergic reactions to food is to avoid the food that causes the allergy. When that isn't possible, you can use medicines. Antihistamines are used for mild reactions, and epinephrine for serious reactions.

For mild allergic reactions, people often try over-the-counter antihistamine and corticosteroid medicines first. Bronchodilators may also be used. They relax the airways of the lungs, making it easier to breathe. You can try prescription medicines if over-the-counter medicines don't control allergy symptoms or if they cause side effects.

If you have a severe allergic reaction, you may need a shot of epinephrine. This will relax the muscles that help you breathe. If your doctor has prescribed epinephrine, always keep it with you. Your doctor or pharmacist will teach you how to give yourself a shot if you need it. Talk to your doctor about an anaphylaxis (say "ann-uh-fuh-LAK-suss") action plan.

If you have a food allergy, you can take steps to avoid having reactions to that food. Most important, avoid eating the foods you're allergic to. Learn to read food labels and spot other names for problem foods. When you eat out or at other people's houses, ask about the foods you are served. And you can bring safe substitutes from home.

It's smart to teach your family members, coworkers, and friends what to do if you eat a food that you're allergic to.

Also, you can wear medical alert jewelry that lists your allergies. You can buy this at most drugstores.

The doctor will ask questions about your child's past health and family food allergies. He or she will do a physical exam. The doctor will also ask what symptoms your child has from eating certain foods.

Because food allergies can be confused with other problems, your doctor may do some tests. Your child may have either skin testing or a blood test. These tests can help see what your child is allergic to. An oral food challenge is another way to diagnose a food allergy. Your child will eat a variety of foods as your doctor watches to see if and when a reaction occurs.

Medicine is used to treat some food allergies.

For mild allergic reactions, people often try nonprescription medicines first. You can try prescription medicines if over-the-counter medicines don't control allergy symptoms or if they make you drowsy or cause other side effects that bother you.

For a severe allergic reaction, you may take:

• Epinephrine. It's given as a shot. It acts quickly to relax the muscles that help you breathe. You may need more than one shot if symptoms don't go away. It's used to treat anaphylaxis.
• Antihistamines. They block the action of histamine during an allergic reaction. They help improve symptoms like itching and sneezing.
• Corticosteroids. They help reduce inflammation.

For mild food allergy symptoms, you may take:

• Antihistamines and corticosteroids. They can be used for hives, belly symptoms, or sneezing and a runny nose.
• Bronchodilators for asthma symptoms. They relax the airways of the lungs and make it easier to breathe.

The following health professionals may evaluate and treat mild food allergies:

• Family medicine physician
• Pediatrician
• Internist
• Nurse practitioner
• Physician assistant

An allergist may be needed when:

• You need to identify the foods that trigger allergic reactions.
• Your work or school performance or quality of life is affected because of allergy symptoms or medicine side effects.
• You have other medical conditions, such as recurrent asthma.

You may also be referred to other specialists, such as a:

• Dermatologist, to treat allergic skin problems.
• Pulmonologist, when moderate or severe asthma is also present.

A registered dietitian (RD) can help you keep a balanced diet even when you can't eat some foods. A dietitian can also help you learn how to avoid hidden allergens in foods and give you ideas about how to make substitutions in recipes.

During a mild reaction

• Take a nondrowsy antihistamine, such as loratadine (Claritin), as your doctor recommends. Be safe with medicines. Read and follow all instructions on the label.

During a severe reaction

• Give yourself an epinephrine shot. Keep it with you at all times. Make sure it has not expired.
• Call for emergency help. A severe allergic reaction can be life-threatening and is a medical emergency.

To prevent future reactions

• Avoid the foods that cause problems. And try not to use utensils or cookware that may have been in contact with food that you are allergic to.
• Teach your family members, coworkers, and friends what to do if you have a severe reaction to a food that you are allergic to.
• Wear medical alert jewelry that lists your allergies. You can buy this at most drugstores.

You have a greater chance of developing food allergies if you:

• Have a family history of allergy. If both of your parents have allergies, you are more likely to have allergies.
• Have another allergic condition such as atopic dermatitis or asthma.
• Are young. Infants and children have more food allergies than adults.
• Have a medical condition that makes it easier for allergens to pass through the walls of the stomach and intestines and enter the bloodstream. These conditions include gastrointestinal disease, malnutrition, prematurity, and diseases that impair the immune system, such as eosinophilic esophagitis (EoE).

You have a greater risk for a life-threatening allergic reaction (anaphylaxis) from food allergy if you:

• Have asthma.
• Develop allergy symptoms within minutes of eating the food.

If you or your child has a severe food allergy, always carry epinephrine and know how to use it. You should also wear a medical alert bracelet at all times. Being prepared to immediately deal with a severe allergic reaction reduces the risk of death.

Food allergies occur when your body's immune system overreacts to substances in food you have eaten. This triggers an allergic reaction. Food allergies are more common in young children than in adults.

• Milk, eggs, peanuts, tree nuts, fish, shellfish, wheat, and soy cause most problems in children. Some babies are so sensitive to these foods that if the food is eaten by the mother, drinking her breast milk can cause a reaction. Most children outgrow allergies to eggs, milk, wheat, and soy.
• Peanuts, tree nuts, fish, and shellfish cause most of the allergic reactions in teens and adults. Adults typically remain allergic to the food for life.

Food allergies are most common in people who are atopic. This means that a tendency to have allergies runs in their family. They are more likely to have asthma, other allergies like hay fever, and a skin condition called atopic dermatitis. Asthma can make the reaction to a food more severe.

If you are very sensitive to a certain food, you may have an allergic reaction just by being near where the food was prepared or served.

When your child has a food allergy and then eats that food, your child's body reacts as if the food is trying to cause harm. So it fights back by setting off an allergic reaction. A mild reaction is no fun, but it isn't dangerous. A serious reaction can be deadly.

Allergies tend to run in families. Your child is more likely to have a food allergy if other people in your family have allergies like hay fever or asthma. And food allergies are more common in children than in adults. Children sometimes outgrow their food allergies, especially allergies to milk, eggs, or soy.

The best way to prevent a food allergy is to avoid the foods that cause it. And make sure that you know what to do if your child does eat something that he or she is allergic to.