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 violently 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 cough and wheeze. When the reaction involves the whole body, this can be a severe allergic reaction.
An allergic reaction can happen anywhere in the body. This includes 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
Asthma symptoms, such as shortness of breath, coughing, wheezing
A severe, life-threatening allergic reaction (anaphylaxis). This can cause trouble breathing, vomiting, diarrhea, low blood pressure, fainting, or death.
Many things can trigger allergic reactions. But the most common triggers or allergens are:
Tree, grass, and weed pollens
Natural rubber latex
Animal dander, urine, and oil from skin
Pests such as cockroaches and mice
Allergies can affect anyone. It doesn't matter regardless of age, gender, race, or socioeconomic status. Generally, allergies are more common in children. But allergies can happen at any age. And they can 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 happen slowly over time.
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. For example, in people with certain skin conditions. Or people 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. They may cost more 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.
Treatment will depend on 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 shots (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.
Control dust in the home, particularly your child’s bedroom.
Use air conditioning instead of opening the windows.
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 his or her 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.
Treatments for hay fever (rhinitis) may include:
Medicines for asthma symptoms
Allergy shots (allergy immunotherapy)
Allergy tablets (sublingual immunotherapy)
Decongestants are not recommended for children younger than age 4. Talk with your child’s healthcare provider for more information about allergy medicine.
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, and medicines.
Tests used to diagnosed allergies include skin tests, blood tests, or challenge tests.
The 3 most effective ways to treat allergies are avoidance, allergy shots (immunotherapy), and medicine.
Working with your child's healthcare provider or allergist can help reduce or get rid of allergies.
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 instructions 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 provider after office hours. This is important if your child becomes ill and you have questions or need advice.