Asthma is a condition with variable and reversible airways obstruction, where people have normal lung function most of the time. It compares to chronic obstructive pulmonary disease where inflammation is progressive and considered irreversible.5

Exposing sensitive lung tissue to a trigger stimulus in people with asthma can cause:6,7

·       bronchoconstriction – the airway smooth muscle tightens excessively and resists relaxation so airways are narrowed;

·       oedema – mucosal tissue along the airway can start to swell;

·       excess mucus which can further narrow airways.

Asthma has four common symptoms – wheezing, coughing, shortness of breath, and tightness in the chest. The cause of asthma is still not fully understood, but diagnosis will also take into consideration if there are any triggers that worsen symptoms, and if there is a personal or family history of atopic or allergic disorders. However, additional testing is now expected to confirm an asthma diagnosis.2,3,7