Yeast infection in ears?

[CheerfulYank]

My poor dog (he's 6 and a golden retriever mix) has been suffering with yeast infection after yeast infection in his ears! The vet gives us cleaning stuff and medicine and it clears up, but it seems like it's only about a month and half or so later and he's scratching his ears and crying again.

Does anyone have any experience with this, and what to do to keep them from happening so frequently?

ANYONE? :)

Does he have very hairy ears? I've noticed that dog groomers around here pull hair out of ears as part of the service in order to allow air flow

Yes, he does! Maybe I should trim it a bit or something?

Silly question but does your dog have any allergies??
I only ask as my darling Staffy has food allergies and since we've got them under control, his ear infections have disappeared.

Hmm...maybe? What could he be allergic too, I wonder?

There's allsorts. It wasn't till Staffy boy came up in huge red welts around his collar that the vet suggested an allergy.

We've got it narrowed down to most grains, a protein used in preservatives and brewers yeast.
Now he's on bloody expensive food but clear skin and ears.