My dog has bald spots near and is bleeding!?

so, last week i notice that my dog is getting a rectangular bald spot on her backside near her tail.. I told my husband and he didnt seem to think it was anything.. but then the day after that i notice a spot on her tail (which is docked) that is also balding but its bleeding. well i showed my husband, and he also didnt think it was anything to worry about, and a couple days later he told me it looked like it was going away. well TODAY I notice the OTHER SIDE of her docked tail is now balding and bleeding and it sort of looks like a circle... like the bleeding is a circle. what could this be??