Has she had a full thyroid panel? Blackened, thickened skin is a symptom of thyroid disorders, I do believe…
Thanks, Quercus. Both hypothyroidism and Cushing's disease can cause hair loss and blackening of the skin, so blood work is certainly a good idea, although I haven't gone that route as of yet. She doesn't have any of the other associated symptoms, which reduces my index of suspicion, but I agree that an endocrine workup may be necessary in the not too distant future. Thanks again!
Have you done a skin scraping? I dont know about the black skin but hairloss could be demodex mange. Im not sure if it is common in the breed.
Does she seem overly itchy? Biting at paws? Could be an allergen as well.
I think a skin scraping will likely be the next step, but I wanted to get some opinions first. She may need additional blood work as well to test for endocrine disorders. After the initial treatments I was using the assumption that this was allergic dermatitis, although she doesn't appear to have itching or irritation in the slightest, which does not support that conclusion.
I think I would "opt" for further investigation…. Obviously this is not normal. Maybe a referral to a skin specialist?
And have you talked to her breeder about this and if there is something that he/she might know?
I agree that a veterinary dermatologist would be very helpful, although the nearest one is several hours away. The breeder has been contacted and she isn't aware of any similar conditions in her lines.
Thank you all very much for the assistance… It looks as if a third veterinary visit may be in order. 
Have you notice any other patches of black skin where there is hair? or on the belly were there is no hair?…. many, many Basenjis have areas of mottled skin, especially noticable on Reds that are Tri Factored
Thanks for the response, Tanza. Kaylee is red and white and she does have 'freckles' on her belly, legs, neck, etc. The new black lesions are different in that they are raised and spreading (only a single small area was present when the hair was initially removed, now there are about five large areas). Thus, they are not the natural pigment, but are new and may or may not be indicative of a problem (my feeling is that they are likely related to some sort of as of yet obscure pathology). Thanks again for the help!
Hi all,
Thanks for having this very handy basenji information database. My 1.4 year old darling basenji girl, Kaylee, is having perplexing skin issues. Several months ago she developed an area of circular hair loss that I initially thought resulted from roughhousing at the dog park. When I returned from Christmas break I noticed the area had expanded significantly with skin inflammation. My suspicion was ringworm at that time so I started topical terbinafine (good antifungal) without success. She was then taken to the vet, who also felt it was likely to be ringworm so she was shaved and I started her on oral terbinafine (thank you Walgreens perscription savings plan). When she was shaved I noticed a small black area in the center of the hair loss, but didn't pay too much attention at that time.
About two weeks into the oral terbinafine a second area of hair loss appeared. At this point the shotgun approach was taken and oral cephalexin (antibiotic), fish oil, Benadryl, and topical hydrocortizone were added. There has been some success with hair growing back nicely in the initial area of hair loss with the secondary area holding its own. At present she is only on Benadryl and fish oil once daily with weekly treated baths. Interestingly, the areas have never bothered her in the slightest without licking or scratching; she seems perfectly healthy otherwise, thank God.
With the reasonable success, I have now noticed that the areas of black skin have been expanding under the growing hair, now with several areas present and a black region under the secondary area of alopecia. Hair loss seems to be occurring over one of the the pigmented areas. I have taken her to the vet again and the individual felt that since the hair was growing back there was nothing to be done. I don't think it's black skin disease as it doesn't seem to fit the profile. Does anyone have a similar experience or know of problems that could cause black skin and hair loss in a basenji? Thanks very much for your help and taking the time to read my case report!
Robin and Kaylee