My cat is licking obsessively at her back just above her tail, and now has a patch with lots of tiny round scabs that tend to have clear discharge in huge concentration. She now has no fur, and the patch covers a large majority of her back. I’ve been told it is an allergy to corn, and I have changed her diet a thousand times. She does have digestive problems, so I feed her a combination of Eukanuba Hairball remedy and Purina One Sensative Systems. I occasionally give her a pouch of Whiskas moist food, which is the only thing she doesn’t throw up! What is going on? I live in the desert, so I use hydrocortisone shampoo and another allergy shampoo. I also put hydrocortisone spray on her at night. When I do everything and don’t forget a thing, she starts to get better, but if I don’t wash her back every week, put the spray on, and keep track of her diet (Which I am now slowly switching to soft canned food) she gets worse then before. What can I do?