How do you know if you have candida overgrowth in sinuses?

It is not easy at all to know this. The gold standard is to grow Candida easily in culture . However, getting a sinus culture is at best extremely difficult to do. Even if you are in a ENT office with a flexible scope up your nose to get into a sinus, you can only access all sinuses like that. Even if you get a great specimen, it's very difficult to grow this organism, so you still may not know!