Here's something to check out, it's about all I could find:

Frontal sinus pathology and epilepsy

I think it was on the main epilepsy website where some time ago a discussion like this was held. I forgot what it was, but from what I gathered is certain AED's can contribute to sinus complications (if I recall correctly one person had associated dilantin with nasal polyps - not sure though).

Maybe you can check out the Medications forum and then list off any medications you're taking and then ask if sinus complications are associated to any. I am sure if anyone knows, MrsD would be the person!