What can be cause behind my persistent dry cough?

Chronic cough. The possible etiologies of a persistent dry cough include bronchospasm, post-nasal drip, gerd or some combination of these etiologies. Since the treatment of each of these is completely different, it is important that you return to your doctor if a particular treatment doesn't lead to complete resolution of the cough. If even 1 etiology is untreated, the cough will persist.

Related Questions

What can be the actual cause behind my persistent dry cough?

Many things. There are many things that can cause a persistent dry cough some of which are serious problems. Smoking can lead to a persistent cough so if you are smoking please stop now. Allergies, dry air, infections, medications and heart problems are just some of the things that can cause this. You should have this evaluated by a health care professional.
Etiologies... Usual etiologies include bronchospasm (of any cause), gerd, post-nasal drip or a combination of factors. It needs to be evaluated by your doctor since these all have different treatments.