...your dog is suffering from chronic autoimmune problems, and if she seems to have developed atopic dermatitis such that she has continuing itchy skin which periodically gets really really bad, resulting at times in secondary infections...
...does it make sense to treat her with expensive immunosuppressant medication to help with that problem., if, in fact...
...she may also be developing degenerative myelopathy?
Or, will it make more sense to treat her periodically with steroids, keeping her as comfortable and active as possible, for as long as possible?
Yes, there's much more to learn, and much more to watch and see, and talk to the vet about. But here's some of what I'm thinking about.
And I'm just barely taking care of myself, emotionally, these days.
What do I have pets, again? (don't answer that--purely rhetorical)