Asthma in Children - Exams and Tests
asthma is based on
medical history, a
physical exam, and simple lung function tests such as
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
Lung function tests
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.
- Testing of daytime
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.
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 medicine. An inhalation challenge also may be
done using a specific irritant or
bronchoscopy test involves using a flexible scope called a
bronchoscope to examine the airways. Sometimes airway problems such as tumors
or foreign bodies will create symptoms that mimic those 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. But some experts believe that this test is not useful for monitoring
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:
chest X-ray. A chest X-ray may be used to see whether
something else, such as a foreign object, is causing symptoms.
sweat test, which measures the amount of salt in
sweat. This test may be used to see whether
cystic fibrosis is causing symptoms.
Other tests may be done to see whether your child has health problems such as
nasal polyps, or
gastroesophageal reflux disease.