Bald Cocker Spaniel

Hi,

I am Nushi's Mom. We live in Victoria BC Canada. She is a 14yr old black American Cocker Spaniel.
Nushi has been bald on her back for the past 6 years. The skin has turned black where she is bald as well. It doesn't itch or ooze but the skin is thin and there are little 'bumples' - not pimples or large bumps but kind of a combination of both. No other symtoms except for thickened skin on her nose.We have had every test under the sun.
The hair fell out over a two day period (scared the bejeebers out of me) and now her back from just behind her shoulders to her rump is bald. There has been some regowth around the edges but it is kind of brown puppy hair.

The vets (3) don't know what it is and I am hoping someone has had a similar experience and resolved it.
I think I have attached a photo of her back for reference.
Thanks in advance
Nushi's Mom

I know you said the vets did tons of tests, but make sure they did a thyroid test, the symptoms are very similar.

If everything checked out, it could be allergies, food or environmental. Have they tried putting the dog on an elimination diet?

Have you considered actually going to a dermatologist for animals. They are alot more specialized and would be more familiar with these kinds of problems than the average practicing vet.

If this dog is itchy, the list is very long, because itching from any cause that goes on long enough can cause hairloss, darkened skin in the itchy area. The most common causes of this degree of itchiness are sarcoptic mange mites, atopy (inhalant allergies), bacterial and yeast (Malassezia) infections. There are some uncommon disorders involving sex hormones or growth hormones that can produce darkened skin and hair coat changes.

Malassezia is not always itchy and hyperadrenocorticism (Cushing's) and the
other hormonal problems are not usually itchy, either.