13 year old siamese cat

Question
hi,  there has to be an answer to our problem.  our cat has somehow suffered from sneezing and the running nose for years.  basically 24/7 for 10 plus years.  so it could be an allergent in the house or even the other cat.  i really dont care what is causing it.  i just want it to stop.  he has been to the vet so many times and they havnt found an answer.  he doesnt have an illness of any kind, he just is allergic to something.  they also told me that some cats just sneeze.  i wont take that as the right answer.  i need to know if there are cat drugs for allergies(to dry him up) .  he is perfect otherwise.  its not fair to the cat because no one wants him or will hold him cause he sneezes snot all over you and the house.  i make him now sleep in the bathroom.  it is so unfair.  please if you have a name of a drug he can take to dry him up.  hes so old and should be loved, but its hard.  
thanks
anne

Answer
Anne,

I am not a veterinarian, but some of the things vets can overlook are nose polyps, nose fungi, e-coli (or some other bizarre bacterium) in the upper respiratory tract.  

Has your vet tried culturing the catarrh to see if it is a bacterial infection?

The other thing you can try if it is an allergy is to give the cat a daily allergy pill (under your vet's supervision).

Best regards... Norm.