I have a consistent cough what could be the cause?

Various things...: When i see a bad cough in clinic, and there's no clear infectious source like bronchitis, pneumonia or other type of viral illness, i start to look for things like asthma, gastric reflux, post-nasal drip. It usually takes a good history and exam to figure out the cause. Bottom line, please get checked out and don't let this cough linger!