Diagnosis of asthma

A diagnosis of asthma is based primarily on a physical examination, a medical history and a test of how well lungs work.

Medical history

Your doctor will likely ask a number of questions, such as the following:

• Is there a family history of asthma?
• How often do symptoms occur?
• Does coughing wake your child at night?
• Do the symptoms accompany a cold or are they unrelated to colds?
• Do they occur with exercise?
• Does your child avoid normally enjoyed activities because of breathing difficulties?
• How often do episodes of breathing difficulty occur?
• How long do they last?
• Has your child needed emergency care for breathing difficulties?
• Does your child have any known pollen, dust, pet or food allergies?
• Is your child exposed to cigarette smoke or other airborne irritants?

Lung-function test

The primary diagnostic test is performed with a device called a spirometer, which measures how much air you inhale, how much air you exhale, and how quickly air is exhaled. The results of the test indicate how well the lungs function even when signs and symptoms are not present.

Your doctor may follow up the initial spirometry test with a treatment test. Your child inhales a short-acting asthma drug and then repeats the lung function test with the spirometer. An improvement in results of a second test with the spirometer may help confirm a diagnosis of asthma.

Allergy test

Your doctor may recommend an allergy skin test or allergy blood test if cats, dogs, dust mites, mold or pollen are suspected asthma triggers.