Small red bumps randomly appeared on my dogs skin about a week ago. It started with just a couple on his belly now they are spreading. I did check for fleas and I haven't found a single bug or any "flea dirt". There is a few bumps on his belly, back, chest, and armpits. There isn't a bunch but just some here and there, they seem to be infected and they are very itchy to him. It has been a week and they have not gone away. There has been no changes in his diet or environment other than it is getting pretty cold outside. He is a 7 year old Australian Shepherd and we live in Alaska. Any advice would be greatly appreciated.