Yeast infection in ears

Question
Dear Dr. Gotthelf,

I have a 9 year old pug in good health who has had off and on problems with a yeast infection mostly in his left ear. His ear(s) makes a lot of wax and becomes inflammed. He has been perscribed a topical anti-biotic which clears it up for a 6-8 weeks or so, but then it comes back.  Our vet instructed us to wash his ears and massage into the ear canal with DermaPet Malacetic Otic once a week.  This staves it off further, but eventually I find his ear red and waxy and we have to start all over again.  As you can image, neither party involved is happy about this.

Our vet mentioned that he might have a food allergy.  What kind of foods typically exacerbate ear infections?  He gets dry kibble and an occasional tid-bit of table food, usually vegetables, bread or pieces of meat. He also takes a vet perscribed suppliment made from shellfish for his joint maintenance.

Any input appreciated,

Keith Knecht

Answer
Dogs can have food allergies to a number of proteins including milk, eggs, wheat, chicken, beef, lamb and fish.  The best way to determine if there is a food allergy is to put him on a food that only contains one protein like venison, duck, or to use a hydrolyzed diet called z/d.  You can also make a homemade diet.  Ask your vet about those types of diets. This has to be done for a minimum of 8 weeks with that food being the only thing the dog touches.  You can't even use flavored heartworm pills.  

If the ear disease goes away in the 8 week period, then it is a food allergy and you then add protein sources back into the diet to see if there is a reaction.