What are the causes of asthma??

Many: Although the exact cause(s) for asthma is being debated, about 80% of asthma especially among younger people are related to allergy. Current thinking is that a viral infection is likely the trigger for its development. More recently, an abnormal epithelium (which covers the airways) is considered a major component for the development of asthma. A detailed review is not feasible .

Asthma: Asthma is caused by reactive airways that results in excess mucous production + narrowed airways. Symptoms are usually episodic and triggered by allergies (grasses, pollen, mould) or infections. Some people get exercise-induced symptoms.