Help with forever running nose

[Valdeeves]

I'm not exaggerating when I say my daughters nose has been running since she started to teeth at ten months. She's a very preterm baby - not sure if that has anything to do with it?
The doctor told us her ears were blocked and gave us drops to soften the wax. Her nose stopped and we saw the doctor and he said good. No more drops.
However it's now so constant that I am literally wiping and it flows out. I carry sodden tissues in my pocket all day.
Can someone tell me what this?

Just for the record she's 18 months - so that's almost half of life with a constant running nose. I have been told by the nursery that they don't think it's "normal".