Hello Welcome in H.C.M. I have gone through your query regarding recurrent mucoid nasal discharge. your C.T.Scan and MRI of sinus are normal except mucosal thickening of sinus linings. Your symptoms and radiological reports of C.T. & MRI are favoring allergic sinusitis. this in turn giving you watery and mucus discharge from nose and time to time it also involves the labyrinth thus vertigo appears. Since allergy is not a curable disease only control of symptoms may be achieve by- 1- Avoid the contact with allergen- Here I would like to tell you that try to recollect any new in your life style from the time of symptoms ,it may be any new tooth paste , deodorants , perfume etc. If it is there than try to avoid that. 2- Skin test to identify the allergen and accordingly go for desensitization by suitable vaccine. 3- take anti allergic for long time. 4- Steam inhalation. I hope this will help you. Regards.