Ask a Dog Vet and Get Answers to Your Dog Health Questions
Hello, this is Dr. Jess. I am sorry to hear about your dog!
Had you seen fleas/had she had fleas before you put the medication on her?
Where on her tail is she chewing? At the base of the tail where it meets the body?
It sounds like she is a dog who may suffer from allergies. Some of these dogs will respond to antihistamines and fatty acid supplements alone, while others may require short courses of steroids to decrease the itching/break the itch cycle. The tail is a common area for itching due to flea bites and some dogs can have an allergy to flea bites and just one or two bites can make them very very itchy, so I am glad to hear that you now have her on flea control. If the area is raw and bleeding, it most likely will require a short course of steroids (and sometimes antibiotics if a secondary infection is present), so I would recommend scheduling a vet visit. In the meantime, you can purchase an e-collar (lampshade like collar) to prevent her from further traumatizing the skin. You may also find a topical "hot spot" type spray at the pet store to use on the area, though as I said, she is likely to need prescription strength drugs to resolve the issue. You can also discuss with the vet starting fatty acid supplements (your vet will have these, and you can also find them at the pet store) and an antihistamine such as benadryl: http://www.petplace.com/article/drug-library/library/over-the-counter/diphenhydramine-benadryl.
Please let me know if you have additional questions!