Flonase and oral candida?

Hello there,
While I personally have not experienced this problem with flonase, it is a fairly common side effect. The reason for this is that flonase is a steroid. This helps intranasally for allergies because it reduces inflammation that cause the allergy symptoms, but it also suppresses the immune response in the area (nose and mouth) meaning the body cannot fight off the thrush as easily. Even though the spray is used in the nose, you may find it useful to rinse your mouth out well after each use.
If the problem persists, talk to your doctor about alternative allergy treatments or antifungal medications for the thrush, depending on which problem you find more pressing.