ongoing skin condition in older collie

Question
Hi there-

We adopted a rough collie a couple months ago, and were told that she had very bad flea allergies, and that her previous owners said she had itched/scratched/bit herself constantly all her life. Because of this, she literally has no teeth left, shes broken them all and worn them down chewing on herself. When we got her, she had thin, coarse fur around her head, ruff, feathers and side, but she had a strip of bare skin down her back, no fur on her tail and no fur down her back legs. The skin on her back was raw and swollen and covered in sores, her vulva was swollen and red and she continually scratched. Our vet did full blood work on her, put her on a high dosage of steroids and antihistamines, gave her a steroid spray and put her on antibiotics for secondary infections. After a couple weeks the fur started to grow back, but she still constantly itches. Its been four months now, and she looks terrible. She no longer has patches of missing fur, but her fur is VERY thin all over, very coarse and stringy, she is loosing weight, the base of her tail, vulva, and back right above the base of her tail is swollen and hot to the touch. We put her on a restricted diet of only raw beef/lamb/duck/venison products because the vet thought she might be allergic to chicken or some chemical in the food the other owners had her on. There has been no improvement- she constantly scratches at herself, bites at herself, pulls out clumps of fur. We get temporary relief with oatmeal baths, for a day or two her fur will be soft and her skin almost normal (except around her vulva) bu then it will get coarse and her skin will begin to get irritated again. Her vulva is what concerns me the most, the skin around it is literally the size of a silver dollar, it is just big and swollen like a bitch in heat, and her nipples are also swollen and red. She IS unaltered, we keep trying to get her spayed but every time we bring her in the vet says she would prefer not to do surgery on her in her current condition, and that we need to get weight on her first. We are at our wits end- is it possible that this could be hormone related, since she is intact, or do you think this is just a skin condition? Are there any other routes we haven't been able to explore? Anything would help. Thank you so much for your help!

Answer
If she is still on high doses of cortisone and antihistamines and still itches, then it may be something like mange mites or yeasts rather than allergies.  Ask your vet to treat for sarcoptic mites even though they may not have diagnosed them.  Also, many skin diseases are complicated by secondary yeast infections.  So even if she is on an antibiotic, it ill not kill a yeast infection.  Ask the vet if an antifungal drug like ketoconazole, itraconazole, or fluconazole may be tried to see if it is a yeast infection causing the itching.