you were wise to get this situation checked out because it is possible for a person to leak cerebrospinal fluid (csf) through a nostril and this is a dangerous situation that can lead to a serious infection of the membranes that surround the brain. however since you've had a battery of tests done that have shown the fluid leaking from your nose is not csf then you can rest assured your brain is fine. the fluid coming from your nose must be normal mucus. many people (myself included) suffer from a chronically runny nose. clear fluid coming from the nose can indeed be caused by allergies. there also is an interesting condition called 'gustatory rhinitis ' which is fancy talk for getting a runny nose while eating. since your runny nose comes and goes it does sound like it could be seasonal allergies. only your health care providers can solve this mystery for you. i wish you all the best.
when i bend over clear fluid leaks out of my left nostril it happend last year but it stopped now it happend this week. i have a deviated septum and mucus is always in my throat witch i have to spit contently i am terrified it could be a csf leak i had a mri of the head and it came back clear now it dose not happen all the time i can bend down now and it wont happen it maybe happens twice or once every year right now i have headaches and head pressure on my nose and face and back of head with headaches im also dizzy saw ents and doctors and blood test all came back fine doctors think its anxiet coulditbeallergies