What are these scabs on my dogs skin?

He is a 70 pound pitbull mix and only this summer while brushing him or petting him- i keep finding these large(in height not width) black scabs yet if you pull them off there is just a red area underneath, no blood, puss or any sort of infection. Why does he keep getting these seemingly out of nowhere? so far he has gotten three, one between his shoulder blades, one almost the same spot but further down the back, and another in the middle of the back on near the spine. He is a little over 1 and a half years old and has a shiny, red/tan coat which sheds a bunch but has never had scabs. He has also always itched ALOT, never breaking the skin but biting and itching everywhere. I also treat him monthly with K9 Advantix so it shouldn’t be anything like that as he is mostly an inside dog.

Ok well he may be getting these things called “hot spots”. They are very annoying to a dog and they are somewhat nasty to look at. If you take him tot he vet he/she will give him this special cream for the “hot spots”. If not then get ice, wrap it in a towel, and then you just put it over the spots for about 5 minutes each. I hope everything turn out all right.