Accepted Answer

Hello,
Well, the C/D diet is fine and has likely been prescribed to help acidify the urine to prevent struvite crystals/stones from forming.
By the way, if the urine has not been rechecked since starting the C/D diet, I would strongly encourage you to get a urine test performed.

Now, the dark skin. This is what we call hyperpigmentation and it is generally caused by excessive licking. Therefore, your pet likely has an underlying allergy problem.

Now, there are food allergies and environmental allergies (excluding when there are obvious flea problems).
So, you'll want to give the two links a good read before consulting your vet about the skin.

http://www.petplace.com/dogs/food-allergy-in-dogs/page1.aspx

http://www.petplace.com/dogs/atopy-in-dogs/page1.aspx

The concern with the skin changes is whether or not a secondary bacterial and/or yeast infection is present. Worth having a vet get a look.

Hope that helps
I wish the best for both you and your pet. Please let me know if I can be of any further assistance.
Dr. Andy

Expert:	DrAndy
Pos. Feedback:	99.7 %
Accepts:
Answered:	4/10/2009

Dog Veterinarian

2003 UC Davis Grad, Interests: Internal Medicine, Dermatology, Pain Control, Emergency , Geriatrics