Asthma in Children
Exams and Tests
Diagnosis of asthma is based on medical history, physical examination, and simple lung function tests such as spirometry.
Diagnosing asthma in babies and toddlers is often very difficult. Symptoms may be the same as those of other diseases, such as infection with respiratory syncytial virus (RSV) or inflammation of the lungs (pneumonia), sinuses (sinusitis), and small airways (bronchiolitis). If you have a very young child, spirometry is not practical, so the diagnosis is made based on your report of symptoms.
Repeated wheezing is the key symptom in children with asthma; however, asthma is not the most common cause of wheezing. Still, if your child wheezes frequently, he or she should be checked for asthma, especially if cough and shortness of breath are also present. Many children and teens with frequent wheezing may have asthma but are not diagnosed with the disease.
To make a diagnosis of asthma in your child, your health professional may look for factors associated with asthma:
- Having wheezing attacks more than 3 times per year lasting longer than 1 day and affecting sleep.
- Having parents with a history of asthma or atopic dermatitis or two of the following three symptoms.
- Wheezing not associated with colds.
- Hay fever (allergic rhinitis).
- A high eosinophil count. Eosinophils are a type of white blood cell often present in allergic reactions.
In an older child, lung function tests can diagnose asthma, determine its severity, and check for complications.
- Spirometry is the most common test to diagnose asthma in older children. It measures how quickly a child can move air in and out of the lungs and how much air is moved. The test helps your health professional decide whether airflow is decreased because of inflamed bronchial tubes
and whether the tubes can return to their usual size in a short time after using medication. The test is recommended at least every 1 to 2 years after asthma treatment has begun.
- Testing of daytime changes in peak expiratory flow (PEF) is done over 1 to 2 weeks. This test is needed when your child has symptoms off and on but has normal spirometry test results.
- An exercise or inhalation challenge may be used if the spirometry test results have been normal or near normal but asthma is still suspected. These tests measure how quickly your child can breathe in and out after exercise or after using a medication. An inhalation challenge also may be done using a specific irritant or allergen.
- A bronchoscopy involves using a flexible scope called a bronchoscope to examine the airways. Occasionally airway problems such as tumors or foreign bodies will create symptoms that mimic those of asthma. The test might be done if there is unequal wheezing in the lungs or a poor response to asthma therapy. Biopsies of the airways can be done to look for changes characteristic of asthma.
A newer test to monitor asthma is the NIOX nitric oxide test system. This test measures nitric oxide in exhaled air. A decrease in nitric oxide suggests that treatment may be reducing inflammation caused by asthma.
Regular checkups
You need to monitor your child's condition and have regular checkups to keep asthma under control and to review and possibly update your child's daily treatment and action plans. The frequency of checkups depends on how your child's asthma is classified. Checkups are recommended:
- About every 6 to 12 months for children with mild intermittent or mild persistent asthma that has been under control for at least 3 months.
- Every 3 to 4 months for children with moderate persistent asthma.
- Every 1 to 2 months for children with uncontrolled or severe persistent asthma.
During checkups, your health professional will ask you and your child whether symptoms and peak expiratory flow have held steady, improved, or become worse, and about asthma attacks during exercise, at night, or after laughing or crying hard. You and your child track this information in an asthma diary. Your child may be asked to bring the peak expiratory flow meter to an appointment so your health professional can see how he or she uses it. Based on the results, your child's asthma category may change, and your health professional may change the medications your child uses or how much medication he or she uses.
Tests for other diseases
Asthma sometimes is hard to diagnose because symptoms vary widely from child to child and within each child over time. Symptoms may be the same as those of other conditions, such as influenza or other viral respiratory infections. Tests that may be done to determine whether diseases other than asthma are causing your child's symptoms include:
- A chest X-ray. A chest X-ray may be used to see whether something else, such as a foreign object, is causing symptoms.
- A sweat test, which measures the amount of salt in sweat. This test may be used to see whether cystic fibrosis is causing symptoms.
Tests to identify triggers
If your child has persistent asthma and takes medication every day, your health professional may ask about his or her exposure to substances (allergens) that cause an allergic reaction. For more information about the following tests, see the topic Allergic Rhinitis.
Allergy tests include:
- Skin tests. The skin on the back or arms is pricked with one or more small doses of allergens that might cause an allergy. The amount of swelling and redness at the sites of the skin pricks is measured to see which allergens cause a reaction. Skin tests are quick, simple, and relatively safe. Skin tests are necessary if you feel your child may need allergy shots (immunotherapy).
- Enzyme-linked immunosorbent assay (ELISA). A blood sample is taken from a vein and tested for immunoglobulin E (IgE) antibodies, which are produced in response to particular allergens.
Other tests may be done to see whether other conditions such as sinusitis, nasal polyps, or gastroesophageal reflux disease are present.
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| Author: | Maria G. Essig, MS, ELS | Last Updated: March 22, 2007 |
| Medical Review: | Michael J. Sexton, MD - Pediatrics Harold S. Nelson, MD - Allergy and Immunology | |
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