Reddit mentions of Vetoquinol Universal Medicated Shampoo for Dogs, Cats and Horses, 16oz

Hair growth problems, bad skin, and funky dog odours are often all the result of microbial overgrowths on the skin. Best thing to do IMO is shampoo therapy. Bath your dog twice weekly for a month in a good, veterinary grade, anti-microbial shampoo, and if you see an improvement, then bath them once a week or so thereafter. This should knock back the microbial population on the skin, and keep it a healthy levels.

Flaky skin, contrary to popular belief, is not generally caused by overbathing, dryness, or using too harsh a shampoo--it's normally caused by having too many microbes on the skin. Topical moisturizers IMO are basically useless.

This is the shampoo I'd recommend, but if you can't find it, then any shampoo containing any of the following ingredients may work:

• benzoyl peroxide
  
• chloroxylenol
  
• sulphur and salicylic acid
  
• chlorhexidene
  
• ketocozanole/micanozole
  
  Coal tar shampoos may help as well, but I'd want to see it combined with one or more of the above ingredients. You can even just use human anti-microbial skin products so long as you remember to let the dog soak, fully lathered, for about 10 minutes before rinsing. An excellent combo of products commonly available at pharmacies is Hibitaine (anti-bacterial acne skin cleanser) and Nizoral (anti-fungal dandruff shampoo) mixed 1:1.