Mange is vet induced in the majority of cases in my opinion when they beat the he11 out of the immune system with multiple vaccines. The best course of action is to NOT do any dips for one thing. That only furhter damages the immune system. No drugs. No medicated shampoos. All these things and chemicals further mess with the dogs own ability to fight things. Sometimes these things will work only to end up with a new problem in pups. Usually UTI's follow. Its a chain reaction from crap that has been done to them in the name of bogus protection.
Feed the dog the best food you can buy (Raw would be good). Boost the pups immune system with Vita C and perhaps some echinachea herb. Wipe lemon juice on the effected areas.