With sarcoptic mange, owners usually only get it if the dog spends a LOT of time in close contact i.e. lap puppy. Then you get a few of them in places like skin folds or under waistbands or straps and they are usually self limiting on humans unless you are immune compromised. It would be a very rare case of sarcoptic mange that had the disappearring and reappearring pustules, but the original problem could have been.
Demodex is usually first noticed in the eyebrow area and around the mouth as a thinning of the hair and usually pops up during times of stress either emotional or physical, puberty is a common time for demodex to appear. It does not usually cause the skin to become inflamed or reddened in any way.
