Food Allergies in a Cat with Previous History of Struvite Crystals

Hi all:

I have a 14 year old male cat that was catheterized 4 years ago with a struvite crystal obstruction.  He has been on Purina UR since and while I don't love the idea of the food, I have been too terrified to change him, because he has had no problems with the crystals since being on the diet.

For the past couple of months, he has been scratching his ears to the point of bleeding, rubbing his whiskers off completely and sometimes opening up sores on his chin.  Mites and Demodex have been ruled out and it appears to be an allergy - likely a food allergy.  

Now I have to find a grain free food, with a novel protein, with a low ph and low magnesium- rule out all of the prescription foods.  It appears that Feline Caviar will fit the bill- but I wondered if anyone had first hand experience with using this food to control production of struvite crystals in cats that have had blockages in the past.  

Does anyone have any other grain free foods that they have had good luck with?  Thanks so much.

Poor kitty, it seems like itchy ears happens a lot with food allergies in kitties.  That's how I knew one of mine had developed an allergy to chicken.  I haven't dealt with crystals but I know a lot of people here have.  One thing you can do when changing food is check his urine pH, you can get the strips on Amazon.  The pH should stay around 6, below 6.5.  The pH will tell you if a food isn't working before he starts to show symptoms.

I am sure someone will be along with food recommendations.

I have not heard of Feline Caviar.  Do you know the level of Magnesium in that food?  I went to their website, and see the ingredients, but don't see anything that shows the Guaranteed Analysis, or really ANY information on them besides the ingredients.

Have you checked Dave's Restricted Diet Magnesium/Phosphorus Pork Dinner canned food?  It does have Brown Rice Flour in it, But otherwise, it might fit the bill.  After all, you're not sure which ingredient in the U/R your guy is allergic to.  It might be corn, it might be chicken Or it might be something else entirely...soy? 

There are hypoallergenic foods out there, but as far as the magnesium level in them, I don't know what they are.  I would have to agree with Denice in either go with a new food that you know is low magnesium and see if he continues to scratch, or use the PH strips to check his urine if you go with a novel protein with higher magnesium.

Hopefully you'll find something that works for him quickly .  Food allergies are the pits, especially with they have other issues