Asthmatics may remain asymptomatic for a long period unless provoked by a stimuli such as a chemical irritant, an environmental allergen, cold or dry air, or rigorous exercise that may precipitate an acute attack. The<unk><unk> <unk>  is a procedure performed to provoke airway obstruction using a stimuli that is known to trigger bronchospasm, sudden contraction of the<unk> es. This<unk>  helps to identify the specific environmental stimuli that triggers an acute attack and also helps to determine the extent of the reaction.
On the other hand, asthma is overdiagnosed.
Asthma bronchial challenge test
Asthma pulmonary function test
Status asthmaticus CT
Asthma CT
Occupational lung disease x ray
Asthma exhaled nitric oxide
Asthma chest x ray
Hypersensitivity pneumonitis CT