Shug (my parents' dog, age 4) has some serious skin issues. My mom took her to the vet in July and the vet said it was flea allergies and gave her a steroid (Depo Medrol) shot. It stopped the itching for a little while, but the hair loss has continued. She's hairless halfway up her back now, with some scabbing. She's itchy all the time, not just on the hairless parts, but all over.
According to her past vet records, she had "mange" as a puppy. No indication as to whether it was scabies or Demodex. But she got a lot of dips, so I think it was probably Demodex....scabies are relatively easy to get rid of and I don't think she'd have needed that many dips. And I guess if they had it as a puppy, they're more prone to getting it later in life. Also that steroids can trigger an episode

.
Anyway, from what I've read about demodex, it seems that in adult dogs, it's almost always a sign of an underlying health problem that's weakening the immune system.
So. If she goes back to the vet, what tests should we ask for? I was thinking just standard bloodwork, plus a full thyroid panel. Anything else?
I'm going to suggest they switch her to TOTW or EVO, I guess grains aren't good for Demodex dogs. She's currently on Chicken Soup. If it comes to it, I think my mom would be willing to go raw/homecooked, but she works full time and I hate to put extra demands on her time.