Hello, I have Chiari I, Syringomyelia, Pseudotumor Cerebri and Empty Sella Syndrome. I have not had the surgery as my case is mild. I have heard that the Empty Sella can cause a chronically runny nose. I have had one of those for years, have been tested for allergies and have no allergies. So after looking back I would guess that mine is from the Empty Sella condition or the PTC either one. If you are having increased pressure within the skull the pressure is said to cause it. In case you are not sure, Empty Sella is basically a flattened pituitary, in most cases the pituitary still functions normally, it just is flat on an MRI scan you can see it. It can be congenital as Chiari is or caused by a tumor on the pituitary or from chroinically raised intracranial pressure. Hope this helps. Chiairi3