My dog's underside (mainly armpits and under his lower legs) has numerous little dark/brown marks on him. At a glance the marks look like scabs but there not. I cannot scrap them off so they're not scabs. He no longer urinates in his cage so I want to rule out his piss giving him rashes (meaning he lays on his own urine). I'm guessing it's an alergic reaction. he's a mostly white dog so it's very noticeable. if you can give any insight i'd appreciate that.