lysine not working food allergies maybe

Hello everybody my 2 yr old Rex has been on Lysine 500mg twice a day from a month now. It doesn't seam to be making any difference in his Sneezing, he also has bad gas and a cronic ear infection. In early post I explained we had been to the vet multiple times over and over pills, ointments shots and test for Fiv and leukemia. I can not long afford guess from the vets, I started doing research online to see if I could find somebody with similar experience and found this site. After more research I have found that food allergies can cause all the above mentioned symptoms. Has anybody here had this type of problem? If so what food did you switch too, I have 4 cats so everybody will eat the same and it must be dry and a good brand of pet food. How long did it take for your cat to respomd? Any help is grateful. Thank you

The gas might be caused by parasites or diet.  Have you had him checked for parasites recently?  Also, you might try a grain-free canned food to see if that helps.  If you feed dry, look for a good grain-free dry food.

Regarding the sneezing, I'd ask the vet to culture any nasal discharge to see if there's a secondary infection going on.