My sister, who has always had allergies, moved from Michigan where they
were under contorl to Tenn where everything went haywire. The airborne
allergies became worse but it was the cough that became chronic that
concerned her. Turned out she's allergic to wheat. After all these
years. Her allergist said that her body just couldn't supress it with
all the airborne changes it was going thru in her environment. If she
even takes one bit of something with wheat in it she starts coughing.
We've been in a restaurant and the waiters think she needs Heimlich
it's so bad. Of course, she eats whatever she wants but does cough
badly when it has wheat in it.  I'm glad it's not a lung problem and
hope you figure out something soon. Cyberhugs, DiW

don't forget to keep track of smells that make you cough, too.  glad to hear
everything is normal for you, sweetie!

kate
Well, the good news is that the upper GI did not show any structural
problems at all, everything normal. The bad news is I don't have any
explanation for the coughing. I guess the next thing is to keep a food
journal and see if there's a particular food triggering the coughing spells.

DeeTee

Well, each thing that gets ruled out, narrows the field of possible causes.  
Perhaps it is somehow allergy ro sinus connected.  I've noticed since moving
north, eating always makes my nose run!  I have to eat with tissues handy,
even if the food isn't spicy.  If that response were in my lungs or throat
rather than sinuses, I'd be coughing.

I'm glad you don't have to be dilated and hoping they find the problem soon.