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.

The immune system makes large amounts of the antibodies called immunoglobin E (IgE). This is a complex chemical weapon that attacks and kills the “enemy.” Each IgE antibody exactly targets a certain allergen or thing that causes the allergy. In this way, inflammatory chemicals are made and given off. This causes the child to feel some bad or even life-threatening symptoms.


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 in 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, wheezing
  • Difficulty breathing
  • Low blood pressure during a severe reaction


Although many things could trigger allergic reactions, 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
  • Bug stings
  • Cockroach waste and body parts

Risk Factors

Allergies can affect anyone, regardless of age, gender, race, or socioeconomic status. Generally, allergies are more common in children. However, allergies can happen at any age, or come back after feeling well for many years.

There’s a tendency for allergies to happen in families, although the exact reason isn’t yet understood. Often, the symptoms of allergies happen slowly over a period of time.


To diagnose an allergy, your healthcare provider will give your child an exam and take his or her health record. He or she may also do these tests:

  • Skin test. The skin test is a way of measuring the level of IgE antibodies to certain allergens. Using diluted solutions of certain allergens, the healthcare provider either gives the child a shot with the solutions or puts them directly on the skin by making a scratch or small puncture. A small red area on the skin means that the child had a reaction. Skin testing may not be done on children who have had a severe life-threatening reaction to an allergen or have severe dry skin (eczema).
  • Blood test. The blood test is used to measure the child's level of IgE antibodies to specific allergens. One common blood test is called radioallergosorbent test or RAST. A newer blood test called ELISA is also available.
  • 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.
  • Nasal smear test. This test is done to confirm if the child has allergies. It checks the amount of eosinophils in the nose. An eosinophil is a type of white blood cell that goes up during an allergic reaction.


Your healthcare provider will figure out the best treatment for your child based on:

  • Your child’s age
  • Your child’s overall health and medical history
  • How sick your child is
  • How well your child can handle specific medications, procedures, or therapies
  • How long the condition is expected to last
  • Your opinion or preference

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

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

Suggestions for avoiding allergens are:

  • Stay indoors when the pollen count is high and on windy days.
  • Dust-proof the home, particularly your child’s bedroom.
  • Use air conditioning instead of opening the windows.
  • Think about putting a dehumidifier in damp areas of the home, but remember to clean it often.
  • Have your child wear a face mask if playing outside when the pollen count is high.

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

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

Treatments for rhinitis may include:

  • Antihistamines
  • Decongestants
  • Medicines for asthma symptoms
  • Allergy shots

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

  • 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, challenge test, and nasal smear test.
  • The three most effective ways to treat allergies are avoidance, allergy shots, and medicine.
  • Working with your healthcare provider or allergist can help cut down 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 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.