Cough evey day in mid of night. Ok.

Dear doctors. I have allergy of dust. Have shown it to many doctors everybody has suggested to avoid dust and doing home cleaning and all. Their prescribed drug work for a week only. Now from last one week every day in mid of night when I go in deep sleep Sudden cough starts due to which I am not able to sleep after 3Am Continuous cough is their by 6 morning it subsidizes automatically. But in this 3 hours it feels like my throat pain has gone high and not able to bear the same. I have to keep taking cofsil or lenzol tablets woth cough syrups which does not help in the same. Please suggest some best allopathic or aurvedic medicine. Note- I do not have fever or cold anything. Only I get cough in mid night and that last till morning and from morning everything becomes OK.