As far as I have heard, "puppy strangles" or Juvenile Cellulitis, only occurs in puppies, and is rare in adult dogs. It is curable and a puppy can recover well with no long term ill effects.
You could "google" this and there is lots of information out there about it. There's some good info on this page:
You could also maybe discuss this with a vet. Some vets are happy to have a short phone discussion about any issues, especially if you are thinking about adopting a pup. But as they are very busy, you might have to arrange a time to speak to them. Ask at a vet's reception area.