Skin problem is a very difficult to cure even for human cases. I guess there is no good vets for this problem.
I only suggest you to try some natural remedies.
I also suffered so long from skin problem myself, but luckily found a good Chinese doctor in Singapore.
And also I studied about soap. Those pet shampoo are nothing different from the kitchen soap, just imagine how harmful they are. Better forget about it even they say this is "natural". NO. In the nature, there is no soap or shampoo. Wash too much the skin cause a lot of problem.
Try not to use any cleansers. If you cannot take it, choose the natural soap which are hand made cold process soap, containing more olive oil. They are very gentle. Only hand made soap, not the commercial one, I also learned how to make it myself for my own use and for my dogs and cats.
Maybe nice to massage the skin with olive oil or coconut oil?
Skin needs oil. My friend told me she cleaned the cat ear with coconut oil.
Also can suspect the diet.
I only go for natural remedies. There is a herbal vet in England, but also in Malaysia, there is a clinic selling the herbal medicine. I don't know whether they are good as vet or not, but recently my kittens has recovered very effectively from the severe diarrhea with their ayurvedic medicine. They are in Batu Cave, worth to check?
http://kmvetpharm.com.my/site/index.php?cat=7