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Asthma
Definition
Asthma is an inflammatory disorder of the airways, which causes
attacks of wheezing, shortness of breath, chest tightness, and
coughing.
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| Alternative Names
Bronchial
asthma; Exercise-induced asthma
Causes, incidence, and risk factors
Asthma is caused by inflammation in the airways. When an asthma
attack occurs, the muscles surrounding the airways become tight
and the lining of the air passages swell. This reduces the
amount of air that can pass by, and can lead to wheezing sounds.
Most people with asthma have wheezing attacks separated by
symptom-free periods. Some patients have long-term shortness of
breath with episodes of increased shortness of breath. Still, in
others, a cough may be the main symptom. Asthma attacks can last
minutes to days and can become dangerous if the airflow becomes
severely restricted.
In sensitive individuals, asthma symptoms can be triggered by
breathing in allergy-causing substances (called allergens or
triggers). Triggers include pet dander, dust mites, cockroach
allergens, molds, or pollens. Asthma symptoms can also be
triggered by respiratory infections, exercise, cold air, tobacco
smoke and other pollutants, stress, food, or drug allergies.
Aspirin and other non-steroidal anti-inflammatory medications (NSAIDS)
provoke asthma in some patients.
Approximately 20.5 million Americans currently have asthma. Many
people with asthma have an individual or family history of
allergies, such as hay fever (allergic rhinitis) or eczema.
Others have no history of allergies.
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