I recently finished my cat on the 12 week meat elimination diet. I have a 12 year old rescue cat who I have only had for 6 months. The vet/shelter had her on Royal Canin Satiety biscuits for 9 months as she's a chunky girl so I continued with this as her coat was like velvet. I also started feeding her human grade kangaroo mince, chicken fillets, cooked lamb, raw beef which she absolutely loved but then she started losing hair on the back of her ears from scratching about 3 weeks after I got her so I figured it must be something I'm feeding her or it's environmental so my vet prescribed a topical anti inflammatory spray which eased her discomfort.
I put her on Royal Canin Hypoallergenic biscuits but she was so miserable and appeared to be sulking because she couldn't eat any raw meat, I was also concerned that the biscuits had no Taurine which is essential to cats health and found in raw meat so I rang the vet and asked for a wet food equivalent and so she's been eating the Hills Prescription z/d tin food which has Taurine but it looks and smells revolting. She reluctantly ate it and the scratching eased but not completely after 12 weeks. I started giving her roo mince again and I noticed the scratching increased so I then stopped and moved on to raw lamb fillets and the scratching eased a bit so I tried her on raw turkey fillets and having about the same result as the lamb. I'm not going to give her beef or chicken as they are apparently known allergens so not sure really what the problem is, her hair has mostly grown back on her ears though.
I've also checked the plants in my yard as some plants like ivy are toxic to cats and I have ivy growing all over my fence so it could be this. Here's a link with toxic plants that can cause itching. http://www.petmd.com/cat/emergency/poisoning-toxicity/e_ct_poisonous_plants
I hope your cat improves, it really is trial and error with cat allergies.
I put her on Royal Canin Hypoallergenic biscuits but she was so miserable and appeared to be sulking because she couldn't eat any raw meat, I was also concerned that the biscuits had no Taurine which is essential to cats health and found in raw meat so I rang the vet and asked for a wet food equivalent and so she's been eating the Hills Prescription z/d tin food which has Taurine but it looks and smells revolting. She reluctantly ate it and the scratching eased but not completely after 12 weeks. I started giving her roo mince again and I noticed the scratching increased so I then stopped and moved on to raw lamb fillets and the scratching eased a bit so I tried her on raw turkey fillets and having about the same result as the lamb. I'm not going to give her beef or chicken as they are apparently known allergens so not sure really what the problem is, her hair has mostly grown back on her ears though.
I've also checked the plants in my yard as some plants like ivy are toxic to cats and I have ivy growing all over my fence so it could be this. Here's a link with toxic plants that can cause itching. http://www.petmd.com/cat/emergency/poisoning-toxicity/e_ct_poisonous_plants
I hope your cat improves, it really is trial and error with cat allergies.