Mange is usually caused by a tiny mite called Demodex canis.
This mite is too small to be seen by the human eye and can only be seen under the microscope.
All dogs and people have some sort of these mites on their body, and most of the time they are completely harmless.
Puppies acquire these mites when they're born from their mother.
And in the majority of cases the immune system is able to keep the mites under control.
It is only a problem when the immune system cannot control the number of mites on the body.
This normally happens to puppies and adults with immune problems, also some dog breeds seem to more affected than others.
Infections are classified as either localized or generalized, this depends on how widespread the lesions are over the dog's body.
Normally localized mange heals by itself over the course of 6-8 weeks.
Small areas of affected skin looks very similar to ringworm with the principal clinical lesions being around the eyelids, the lips, and the corner of the mouths.
If your dog has generalized Demodectic mange they will likely need systemic treatment from your veterinarian.
This usually involves something like an amitraz dip or other miticide.
Also the affected areas tend to be shaved or clipped short to allow better access to the affected skin areas.
One of the most common protocols involves many treatments over a 60 day period.
If you notice any patches of hair loss on your puppy it's always best to contact your veterinarian immediately.