What are allergies in children?

Allergies are problems of the immune system. Most allergic reactions happen when the immune system reacts to a “false alarm.” Normally, the human body defends itself against harmful things, such as viruses or bacteria. But sometimes the defenses attack mostly mild things, such as dust, mold, or pollen.

Normally, allergens are harmless. But when a person has allergies, the body thinks these allergens are harmful. The body then attacks allergens with antibodies called immunoglobulin E (IgE). These antibodies are attached to special cells called mast cells. Allergens stick to the antibodies. This makes the mast cells release histamine and other chemicals causing an allergic reaction. When the chemicals irritate nearby nasal tissue, this causes nasal allergy symptoms. When this happens in the lungs' breathing tubes, it can cause asthma symptoms, such as coughing and wheezing. When the reaction involves the whole body, it can be a severe allergic reaction called anaphylaxis.

What are the symptoms of allergies in a child?

An allergic reaction can happen anywhere in the body, including the skin, eyes, lining of the stomach, nose, sinuses, throat, and lungs. These are the places where immune system cells are found to fight off germs that are breathed in, swallowed, or come in contact with the skin. Allergic reactions can cause:

• Stuffy nose, sneezing, itching, or runny nose, and itching in ears or roof of mouth

• Red, itchy, watery eyes

• Red, itchy, dry skin

• Hives or itchy welts

• Itchy rash

• Asthma symptoms, such as shortness of breath, coughing, or wheezing

• A severe, life-threatening allergic reaction called anaphylaxis. This medical emergency can cause trouble breathing, coughing, vomiting, diarrhea, low blood pressure, fainting, or death. Call 911 right away if your child has these symptoms.

What causes allergies in a child?

Many things can set off allergic reactions. But the most common triggers or allergens are:

• Tree, grass, and weed pollens

• Natural rubber latex

• Molds

• Dust mites

• Animal dander, urine, and oil from skin

• Foods

• Medicines

• Feathers

• Bee stings

• Pests, such as cockroaches and mice

Which children are at risk for allergies?

Allergies can affect anyone. It doesn't matter regardless of age, gender, race, or socioeconomic status. Generally, allergies are more common in children. But they may occur at any age. Allergy symptoms may also come back after being in remission for many years.

Allergies tend to happen in families, but the exact reason isn’t yet understood. Allergy symptoms often develop slowly over time. Children who have eczema or asthma are more likely to have allergies than children who do not.

How are allergies diagnosed in a child?

To diagnose an allergy, the healthcare provider will take a complete health history and examine your child. The provider may also do these tests:

• Skin test. This is the most common allergy test. Skin tests measure if there are IgE antibodies to certain allergens (like foods, pollens, or animal dander). A small amount of diluted allergen is placed on the skin. The area is pricked or scratched. If a person is allergic to the allergen, a small, raised bump (like a mosquito bite) appears after about 15 minutes. Testing for many allergens may be done at the same time. An allergist may also do an intradermal test. In this test, a small amount of allergen is injected just under the skin. This type of skin testing is more sensitive than prick or scratch testing. Skin test results are available right after the testing is done.

• Blood test. Blood tests for allergies measure IgE antibodies to certain allergens in the blood. The testing that is most often used is called RAST (radioallergosorbent test). Blood tests may be used when skin tests can't be done, such as in people with certain skin conditions or those with a very recent severe allergic reaction. A positive blood test does not always mean that you have a certain allergy. Any positive blood test needs to be interpreted by a healthcare provider who is familiar with the tests and knows your child's health history. These tests take longer to get results. It may be more costly than other allergy tests.

• Challenge test. This test is supervised by an allergist. A very small amount of the allergen is given to the child by mouth. Or it is breathed in. Only a challenge test can figure out how severe an allergy is. Skin or blood test reactions only tell the likelihood of having any type of reaction, not what that reaction will be.

Any positive test needs to be explained by a healthcare provider who is familiar with the test and your child's health history.

How are allergies treated in a child?

Treatment will depend on what your child is allergic to as well as your child’s symptoms, age, and general health. It will also depend on how severe the condition is.

The symptoms of allergies sometimes look like other conditions or health problems. Always see your child's healthcare provider for a diagnosis.

The 3 most effective ways to treat allergies are avoidance, allergy immunotherapy, and medicine. Avoidance means staying away from something that gives you an allergic reaction.

Suggestions for staying away from allergens are:

• Stay indoors when the pollen count is high and on windy days. Check the pollen count on a weather report, app, or online.

• Control dust in the home, particularly your child’s bedroom. Wash bedding weekly in hot water. Use allergen proof covers on mattresses and pillows.

• Use air conditioning instead of opening the windows if possible.

• Put a dehumidifier in damp areas of the home. But remember to clean it often.

• After playing outside when the pollen counts are high, have your child take a bath or shower, wash their hair, and change clothes.

• Take vacations in areas where pollen is not as common, such as near the ocean.

Your child’s healthcare provider will also have suggestions for staying away from the allergens that cause reactions.

Allergy immunotherapy is a way of slowly making your body less reactive to allergens over time. There are 2 forms of allergy immunotherapy: allergy shots, and sublingual immunotherapy (SLIT). Allergy shots are given over many months. A small amount of the allergen is injected under the skin. They are available to treat allergies to mold, pollen, dust, animal dander, and insect stings. With SLIT, your child dissolves a tablet under their tongue daily. This can be done at home. SLIT is available for children with allergies to ragweed pollen and grass pollen. Talks with your healthcare provider to see if allergy immunotherapy is right for your child.

Additional medicines for hay fever (rhinitis) may include:

• Antihistamines

• Nasal sprays

• Decongestants

• Medicines for asthma symptoms

Decongestants are not recommended for children younger than age 4. Talk with your child’s healthcare provider for more information about allergy medicine.

Key points about allergies in children

• Allergies are problems of the immune system. Most allergic reactions happen when the immune system reacts to a “false alarm.”

• Allergic reactions are often caused by tree, grass, and weed pollens, latex, molds, dust mites, foods, animals, and medicines.

• Tests used to diagnose allergies include skin tests, blood tests, or challenge tests.

• The 3 most effective ways to treat allergies are avoidance, allergy immunotherapy, and medicine.

• Working with your child's healthcare provider or allergist can help reduce or get rid of allergies.

Next steps

Tips to help you get the most from a visit to your child’s healthcare provider:

• 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 directions your provider 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.

• 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 healthcare provider after office hours. This is important if your child becomes ill and you have questions or need advice.