Asthma is a common long-term condition that can cause coughing, wheezing, chest tightness and breathlessness.
The severity of these symptoms varies from person to person. Asthma can be controlled well in most people most of the time, although some people may have more persistent problems.
Occasionally, asthma symptoms can get gradually or suddenly worse. This is known as an "asthma attack", although doctors sometimes use the term "exacerbation".
Severe attacks may require hospital treatment and can be life threatening, although this is unusual.
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