What is the reason for the dry cough in the middle of the night?

Dry cough in the middle of the night is suspected to be caused by variant asthma, there may be allergic cough caused, do not rule out the possibility of chronic pharyngitis; you can drink warm water properly when coughing, to ensure that the throat is moist, but it is best to go to the respiratory department of the regular hospital to do blood routine, sputum smear examination.