Bronchial hyper-responsiveness is exaggerated airway narrowing in response to a wide range of stimuli such as allergen, virus, smoke and other pollutants. Even in mild persitant asthma, low grade inflammation will eventually lead to lung fibrosis and damage. To prevent deterioration in lung function, anti-inflammatory inhaler medication should be taken on a continuous basis. Far too often asthma sufferers are misdiagnosed as having bronchitis and treated with antibiotics and cough suppressants.
Physical exercise causes rapid cooling and dehydration of the airways.
The airway lining fluid becomes concentrated and this hyperosmolality stimulates mast cells in the lungs which then release chemicals which cause airway narrowing. There is no allergy involved in this mechanism. It can be prevented by using inhaled bronchodlators or chromolyns before exercise. Inhaled steroids have little effect on this condition. Two thirds will stop wheezing and never develop asthma, while a third may go on to develop asthma.