I have never been able to find a doctor to successfully manage my sinusitis either here or in the west. So good luck with that. Allergic rhinitis and sinusitis usually go hand-in-hand with allergies triggering the rhinitis then the sinusitis. Most larger Bangkok hospitals have allergy clinics where they can de-sensitise you against the allergies but this process takes 2-5 years. The latest theory on nasal lavage is that long term it can be counter productive by destroying the natural immunology that protects the nasal surfaces. A lot of nasal and oral medications can actually make things worse with the "rebound effect". My management of the problem was to avoid things like dust mould cats etc and use of Nasonex (under doctors supervision of course) in times of trouble.