causes of cough
There are many causes of a nonproductive cough, such as: 1  Viral illnesses. 2  Bronchospasm. 3  Allergies. Medicines called ACE inhibitors that are used to control high blood pressure.  Exposure to dust, fumes, and chemicals in the work 1  environment. Asthma.  Blockage of the airway by an inhaled object, such as food or a pill.