Hello I am Dr. Joey. Thanks for trusting me to help you and your pet today. I am a licensed veterinarian with over 16 years of experience. I look forward to working with you.
On my, this does sound truly frustrating. Generally with hair loss in this breed such as you describe, if you have had veterinarians rule out definitively there is no infection (no mites, bacteria, yeast or ringworm) via cultures and skin scrapings, then we turn to some of our other more atypical issues. Such as, this could be color dilution alopecia which occurs in "blue" colored breeds. It is hereditary and causes a patchy rough look to the coat, but it not curable. Alternatively, it could be an immune mediated disease such as sebaceous adenititis or pemphigus. If not already done the absolute best step after ruling out all infectious disease problems properly is for you to have her skin biopsied. This is a very easy process that requires sedation and local block with a few small samples taken from affected areas. This must be sent to a dermatopathologist, not to a regular pathologist. I mention this because it is important to ask if you are headed down this road. In the USA the best dermatopatholgoists are from the Univ of FL Veterinary school. We send samples there regularly. As well, if a biopsy is taken, I would send one sample for deep tissue culture to the lab (bacterial) because sometimes we can have a deep bacterial infection which cannot easily be detected on scrapings.
I am at a point I need to know what questions you have. I hope that the information I provided has been helpful.
Please let me know if for any reason you need further clarification, have more questions, or were expecting a different type of answer.
If you received all the information you needed, then kindly submit a rating.