My apologies, they can be allergic to any number of things. My girl is allergic to everything! If the cortisone injections helped to clear the allergy, I might suggest a dermatologist visit. One that specializes in allergies and allergy injections. Agnes had severe allergies and would break out in horrible rashes that were raised, red and yeasty. I have since started her on allergy injections and she is so much improved. (I am a hesitant one to give steroids long term to cats due to the side effects) I have also switched her food to Royal Canin Ultamino. I was hesitant to change to a prescription diet but after several months of allergy serum injections she was still having the breakouts. The food is specifically formulated for skin/allergy issues and since changing her skin is 1000% better.I wash her once a week. It’s hard to tell from the pic but it’s almost like flat blistered area or some kind of strange rash. My vet thinks it’s allergies but I don’t see how allergies would show like on her face. I brought her to the vet for six weeks for a cortisone shot each week it helped a little to clear it up but now it’s back again. I am at a lose as to what to do now.