eustatian tube dysfunction and allergies.

I am 46 years old and over the last 15 years I have become more 'allergic'. I developed exercise induced asthma and became allergic to cats about this time. A few years after that I started to suffer from seasonal allergies.
About 3 years ago I moved to the Middle East for work reasons. (It is dusty here). After about a year in the region I became allergic to alcohol. (I would get an itchy nose, begin to sneeze and became very full of mucous in the nose and sinus). In the last few months I have had a couple of sinus and ear infections, and I have been left with 'sticky' ears, with the left one being affected more than the right. There is mucous behind the eardrum and I have some tinnitus in the left ear. I am on my 3rd dose of antibiotics, but there seems to be not much improvement. My job involves flying, well it is flying, and I find that my ears usually clear when climbing, but on descent I always have to do the valsalva manoeuvre. They clear more easily if I use a nasal decongestant such as otravine. I am also taking antihistamine. I think that the infection has probably gone, but I have been left with fluid in the ear and seem to have Eustachian tube dysfunction particularly on the left side.
Any suggestions would be gratefully received.

David