Cause of loss of sense of smell? it periodically comes back, but not for long.

Nasal inflammation: Typically this occurs when your nose is inflamed either due to infection, allergies or some other reason. In people who lose their sense of smell intermittently, polyps can also be an issue. You would benefit greatly from a consultation with an ENT doctor. This consultation should include looking in your nose with a fiber-optic or telescope to see whether or not you have polyps. Most cases like yours can be successfully treated with medication.