My dog chases and bites his tail. Our vet gave us something like gena something to spray on ,didn't help. Tail raw , no hair .
Your pet may need prednisone. This is a steroid and it helps with the itch esp if it is an allergy. Did your vet check your pets anal glands? Sometimes when the anal glands are full a dog will scoot his but and chase his tail. Also make sure your pet does not have fleas that can couse a severe itch. If you can not get the prednisone try Benadryl 25 mg 2-3 x daily but I think the pred will help better. Good luck, vetcare