6 yr old labrador bitch on steroids, still scratcging to the point of bleeding. has has skin scrapes and blood tests. still ripping her skin off. using medicated shampoos etc etc. no fur on underbelly, very little coat on legs or face
answers to your questions;'
Dr. Peter has "opted out", and I am Dr. Barbara. I'd like to try to help in this frustrating situation for you both!
The two main causes of severe itchiness and subsequent sores are actually quite easy to treat and often not found on skin scrapings. This would be Sarcoptic Mange, caused by a mite that burrows and is frequently not seen. This would be treated with ivermectin or revolution, and this is the way this is often diagnosed. . .by response to these two drugs.
The second possibility would be flea allergy which can be caused by only one to very few fleas which we would never see. If Tilly is not on Frontline, Revolution, Advantage ,or another veterinarian sold anti flea product monthly I would recommend this.
If treating for fleas and sarcoptic mange (along with any secondary bacterial or fungal skin infections) does not resolve her dermatitis and itchiness, then treating for dermatitis secondary to inhaled, contact, or food allergens is the direction you need to go. One drug that can help with this ultimately is Atopica (or cyclosporin).
Hope this helps. . .please let me know!