A persistent cough is a terribly annoying problem that can significantly affect your quality of life. It is important to know how long this cough has been bothering you, so that we can diagnose what exactly is causing this cough to stick around so long. Depending on your age and past medical history, the answer would also be very different. The fact that you mention nasal drainage and a history of allergies indicates that the constant flow of nasal discharge down the back of your throat could be causing local inflammation that is then causing your cough. The best way to treat this cause would be to start by decreasing the amount of nasal discharge. Over the counter remedies such as loratidine, antihistamines, or other common treatments might be beneficial, depending on your medical history and what has worked for you in the past. Also, nasal saline irrigation can often be very beneficial. Finally, a persistent cough can be a sign of something else that is going on, and should be addressed with a health care professional if it does not go away. Your primary care doctor
will be able to ask more direct questions so that you can reach the correct diagnosis and you can start feeling better.