skin issues

she has patches of missing hair on her back and but and were the hair is missing there is scabby and scaley skin.  the dr put her on an antibiotic ans was told to bath her with dawn dish detergent that was a while ago she is getting a little better but still has alot of scabs and hair loss?

[Aleda M Cheng, D.V.M., C.V.A]

Dermatological disorders can be very frustrating and complex.  Since your dog is not recovering sufficiently from antibiotics alone, the rash may be complicated by a secondary problem.  A condition such as allergic skin disease (Atopy), or hypothyroid disease allows skin to become diseased much more easily and more persistently than if the patient did not have these conditions.  

Demodex, Sarcoptic mange, or flea allergy dermatitis can also be instigators of skin disease.  Dogs with flea allergy can be affected for one month or more by a single flea bite.  Sarcoptic mites are very difficult to find on skin scrapings. Demodex mites are very easily seen on skin scrapings. So,  although your dog's mange test was negative, it just means that your dog does not have Demodex, but your dog could still have scabies.

If there is an allergic component to your dog's skin disease, oral steroids may help your dog to heal faster by eliminating the allergic component.  A good topical flea and tick preventative should also be used.  If Scabies is suspected, Ivermectin or other treatment should be added to the treatment regimen.  Some dogs can have an additional skin yeast infection.  If this is suspected, your dog should be bathed with an anti-fungal shampoo at least once per week, or an anti-fungal oral medication can be added.

Please discuss this with your veterinarian.  Your vet could perform a blood test to test for hypothyroid disease, and can do a tape prep, culture and sensitivity, or fungal assay to check for a secondary yeast or fungal infection.  If there is a seasonal component to your dog's skin problems she may have atopy.  If you have forgotten to place your dog on topical flea and tick preventative, it could be flea allergy, etc.etc....