Don't worry at all about sinus fungus being fatal. I have had sungus in my sinuses for years simply because if fungus is in your body, it is more than likely it is going to be in your sinuses too. I've noticed when my sinuses and the inside of my nose area itches, it is when I am taking the supplements to get rid of it. This tells us that whatever we are taking is working. So don't let the itchiness stop you. It just means that your supplements are working so keep at it. THe itchiness means die-off if you are taking stuff to get rid of the candida. Fungus in sinuse will not kill you and is not fatal but it DOES need to go.