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Quick GuideAsthma Symptoms, Causes, and Medications
What is the difference between childhood asthma and adult-onset asthma?
Symptoms of asthma in children may come and go, while symptoms of adult-onset asthma may be continuous. People with adult-onset asthma may need to take medication every day to manage asthma.
Adults tend to have lower lung capacity (the volume of air you are able to take in and forcibly exhale in one second) after middle age because of changes in muscles and stiffening of chest walls. This decreased capacity may cause doctors to miss the diagnosis of adult-onset asthma.
How is adult-onset asthma diagnosed?
Your asthma doctor may diagnose adult-onset asthma by:
- Taking a medical history, asking about symptoms, and listening to you breathe
- Performing a lung function test, using a device called a spirometer to measure how much air you can exhale after first taking a deep breath. The device also measures how fast you can empty your lungs. You may be asked at some time before or after the test to inhale a short-acting bronchodilator (medicine that opens the airways by relaxing tight muscles and that also help clear mucus from the lungs).
- Performing a methacholine challenge test. This asthma test may be performed if your symptoms and spirometry test do not clearly show asthma. When inhaled, methacholine causes the airways to spasm and narrow if asthma is present. During this test, you inhale increasing amounts of methacholine aerosol mist before and after spirometry. The methacholine test is considered positive, meaning asthma is present, if the lung function drops by at least 20%. A bronchodilator is always given at the end of the test to reverse the effects of the methacholine.
- Performing a chest X-ray. An X-ray is an image of the body that is created by using low doses of radiation reflected on special film or a fluorescent screen. X-rays can be used to diagnose a wide range of conditions, from bronchitis to a broken bone. Your doctor might perform an X-ray exam on you in order to see the structures inside your chest, including the heart, lungs, and bones. By viewing your lungs, your doctor can see if you have a condition other than asthma that may account for your symptoms. Although there may be signs on an X-ray that suggest asthma, a person with asthma will often have a normal chest X-ray.