Asthma is a chronic lung condition characterized by inflammation and narrowing of the airways. Asthma results in symptoms of cough, wheezing, tightness in the chest and shortness of breath.

Asthma symptoms vary from person to person. Common triggers that lead to asthma symptoms include environmental allergens such as pollens, dust mites, moulds and animal danders, irritants such as cigarette smoke, exercise, emotional stress, and respiratory infections.

Asthma affects people of all ages, but it most often starts during childhood. Its cause is unknown but researchers think some genetic and environmental factors interact to cause asthma. Treating asthma early may prevent long-term lung damage and helps keep the condition from worsening over time.