For the past year or so, two of my Chihuahuas have chewed the hair off their tails and butts, up to about their back hips.
I have taken them to the vet several times, and they suggested things like "allergic to fleas", "food allergy", stress, and any number of fungus, bacteria, and other such infections. I have tried a dozen creams and sprays, flea medications, and changed their foods a few times. Nothing even seems to phase it.
The first one to start doing it started doing it about a week before she went in labor with a litter of pups and has just never stopped. The second one I rarely see biting or scratching, but have seen with fresh marks where she has been.
If I bathe them every day using the dawn dish detergent used to clean animals found with crude oil from spills, it seems to ease the itching a little, and some of the hair tries to come back. However, it can get expensive to have to keep buying detergent for them and the dishes. I also doubt it is good to bathe dogs that frequently.
Any suggestions or ideas what it might be?