Suggest Treatment For Dry Hacking Cough When Diagnosed With Deviated Septum

HI, My son is 19 years old and a very healthy, strong level 10 gymnast. His health is excellent. About three weeks ago he developed a dry, consistent hacking cough. I took him to the dr. and she gave him an antibiotic for 10 days. We are seven in and it has lessened a little, but remains. I called again today but our regular dr. is on vacation. Her sub prescribed a Z-pack, which I have not gone to pick up yet. A nurse suggested saline and flonase. My son has a significant deviated septum, so he typically just ends up blowing his nose constantly, although I don t know if his biology is related to that or not. I m getting worried. Any thoughts? THank you!