I know it's scary, but most pups have the mites that cause demodectic mange and generally grow out if it. Only 10% of all pups don't, and those are usually the ones with some underlying health issues. Even in rescue, we can see an outbreak after they come to us, but it generally clears up on it's own with good nutrition and care. Stress, bad nutrition and a depressed immune system due to neglect are usually the culprits. I will stress that good food is very important with pups that have outbreaks. Spending a little extra money on a good quality food will work wonders IMHO.