GSD skin condition

Question
Dear Hillary,

We have a 2 1/2 mnths old german shepherd puppy named Sam. At first, he had these sort of pimples filled with clear liquid on the hairless part of his skin. Days ago, I noticed small red ulcers around them and under his back limbs, and the liquid turned grey! He also had two more pimples of these on his chest. He doesn't seem bothered becuase his playful happy behaviour hasn't changed. I would want ot know the common or scientific terms for this skin condition under which i can make some research, helpful resources, the possible causes (diet, shampoo,..?)and how serious this is.

Thank you so much.  

Answer
Hi Amy!  I would definitely take him to your veterinarian to have him tested for mange.  Mange is very common in puppies.  Sarcoptic mange which is caused by sarcoptic mites is very commonly passed on from mother dog to pups.  Demadex mange, caused by demadex mites is very contagious and the pup could have gotten it from any animal he had been in contact with.  Either type of mange is very easily diagnosed and treated.  
First your veterinarian will perform a skin scraping, by gently scraping some skin cells and studying them under a microscope.  This will determine whether or not their are any parasites present.  If there are (which it truly sounds as though there are) your veterinarian will give him an injection of a medication called Ivermectin.  He may also send you home with some Ivermectin pills and antibiotics.  This will clear the condition up very quickly.
I hope this helps and congrats on your new pup!
Hilary