What is asthma?
Asthma is a chronic disease affecting the tubes that carry air in and out of sufferers' lungs (their airways).
What is an asthma attack?
An asthma attack occurs when a person's airways narrow due to a trigger (e.g. pollen) or an external event (e.g. physical exercise). This narrowing is caused by the muscles of their airway becoming tightened and inflamed. Sticky mucus can also be produced and block these airways even more. All this makes it very difficult to breathe properly during an asthma attack.