Dark scaly spots on the skin can be due to a localized skin infection, most commonly bacterial or yeast, less commonly ringworm/fungal infection or demodex mange mites. The increased licking (which is the way dogs scratch themselves when they are itchy), suggests infection is causing itch. The skin increases pigment as a protective response due to the inflammation. Additionally, older dogs can develop flat pigmented skin areas as an aging change, but anything that is raised or bumpy raises the concern of a melanoma or other skin tumor. I recommend that you take her to your veterinarian for diagnosis and treatment.
Good Luck,
Kimberly Coyner, DVM
Diplomate, American College of Veterinary Dermatology
www.dermvet.com
Thank you so much for your reply! everything you said was VERY helpful!