the other day i noticed a small, crusty kind of rash on my dogs ear. when i scraped off the crust, the fur in that area came off as well. then today i noticed the same kind of crusty spot on the top of his head. it is not red or anything. i will most likely see the vet if it does not get better, but i was just wondering if anyone has any idea what this could be. Should i put hydrogen peroxide on it?