Asthma is a condition when your airways narrow and swell and may produce extra mucus.
Mayo Clinic says this can make breathing difficult and trigger coughing, a whistling sound (wheezing) when you breathe out and shortness of breath.
For some people, asthma is a minor nuisance.
For others, it can be a major problem that interferes with daily activities and may lead to a life-threatening asthma attack.
Asthma can't be cured, but its symptoms can be controlled.
