Hi Neurogurl,
I also have extreme chemical sensitivities. Because Lyme spirochetes produce neurotoxins as a waste product, they may contribute to these sensitivites. However, I would attribute the majority of your chemical sensitivities to the gut issues you mentioned in a previous post.
I was on Flonase about 10 years ago. No immediate reaction, but as a steroid, ultimately it will contribute to fungal issues, so you should only take it if you feel you really need it. It's difficult to find doctors who are willing to do nasal cultures to figure out what's actually going on. You should let your doctor know if you're concerned about taking the medication.
Best wishes!