You're right, this is a tricky one, and you aren't likely to get any definitive answers this way. Top of my list is probably some kind of immune mediated disorder. What about pemphigus as a possibility?
Or systemic lupus erythematosis (SLE)? A lot of the northern breeds are 'poster children' for this kind of thing. Or perhaps a tick bourne disease?
Cancer is lower on my list, not impossible but still there. Hypothyroidism would be even lower. I'm guessing the the unknown shots that you were giving were some kind of long acting steroid injection?
The key here, is we need some more definitive steps as far as workup goes, I'd want to do a lymph node biopsy, and definitely some skin biopsies as well. I'd consider a joint aspirate if the limping seems to be a real issue. Xrays and ultrasound might be in order depending on how high cancer gets moved up the list.
Once we've had a good look at the lymph nodes, hopefully we'll have a better idea of they are cancerous, or if they are reactive. Skin biopsies may be best to do after a course of antibiotics (otherwise you're likely just to see infection there, rather than the underlying cause of the infection). I wish you and your pup all the best.
Vets can't diagnose anything without examining the dog. Likely this dog is a result of a pet store/ byb/puppy mill. Don't use them again.
They all produce unhealthy animals. Try switching to a raw diet. That won't cure things, but may help.
Possibly something in SC is causing this that wasn't in whatever other state you live in. Could well be an allergy to something in the wnvironment or factories there.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.