Rocco has something similar on both of his rear paws. They seem to get irritated when they get wet. My vet seemed to think it was related to allergies (possibly in his food since he was having stomach issues too) and told me to switch to another food. I have been feeding fish and potatoes for a month now and although his stomach is MUCH better, Im not sure about the paws. It is snowy around here and after he came inside from going to the bathroom, I noticed the pads were red again and around the nails were actually bleeding...Good thing Dh bought those boots!
If you come up with any answers, please update the post...