hi, a good diet plays an important part in dog health with good health no skin problem.
Food wise, you can try to read up info. on HCF (home cooked food) or Barf (biologically appropriate raw food)
As for treatment wise, it is best to go those homapathic more natural not harmful rather than using medicine to cure the skin problems. But for homepathic it takes time to see results...we need time & patience