Dog with skin problems

Our three-legged chihuahua, Carolina, suffers from skin problems. This is common in pure-bred dogs from what I've heard.

We adopted her from the San Diego Humane Society over a year ago and she's always had to scratch herself excessively. Sometimes she draws a little blood where she's scratched too hard... We're trying various shampoos and supplements on her to see what helps. In addition to seeing a holistic vet, we even consulted with an animal communicator to see if she could reveal anything about her condition. Apparently she has some deep-seated issues from being mistreated by her previous owners. She lost her front leg because they never bothered to fix it. And by the time they relinquished Carolina to the shelter, her leg was in such bad shape that the only thing they could do was amputate it.

We're just going to have to persist in our search to find her relief.