My terrier was just treated for host specific Mites which show up as black spots on these same areas, her chest, under the pits, inside her ears, around her mouth. I was concerned when I noticed tufts of fur trailing her. After 2 weeks of my attending to her with only partial success I got a Frontline prescription with a proper diagnosis from a vet. A simple scraping under the microscope yielded instant confirmation on what ailed her. My rubbing her with strong adversive smelling oils, must have slowed things down some. I am to strengthen her immune system (Echinacae) and add Omega 3 oils (Hemp) to her high quality diet. The environment needs vigorous cleaning, cover beds with white towels, a good way to check what falls off and your progress. Don't let your dog suffer from itching, give him the proper help.
I have a three year fox terrier. He is white with a few black spots. His belly is kinda pink with some dark spots. The last day or so I have noticed that his belly is turning dark. It doesn't seem to itch but just looks strange. Do you have any idea what this could be? It doesn't seem to bother him.