When is it time to put my dog down

I've read some of the other similar questions...but I suppose my situation is unique. I rescued my german shepherd at about 4 months old. She is currently a little over 7 years old. She is the absolute best dog (in my opinion).

That being said, she has discoid lupus which essentially eats away at her skin. Two months ago it got so bad it cut into an artery on her nose and I had to take her into the vet in the middle of the night.

She was on prednisone for about 1 year at a super low dose...but obviously it didn't help too much. Now she is on 24 mg of Medrol / day. It helps some...but her nose and skin are not healing...more or less they're just sustaining.

My question...she can't stay on Medrol forever because a) her liver & kindeys will shut down and b) it causes her to "leak" everywhere and she has explosive diarhea in the house.

I'm really struggling with what to do because if I take her off the Medrol, it will cause the Lupus to attaack to be more severe. Help!

our family has always dreaded this sort of situation. But what we look at is quality of life. Is the dog happy? are they going to stay happy? are they in constant pain? is it going to get worse? these are all questions that you have to ask yourself. you also have to think of your baby. as they get older they are going to want to touch and play with the dog. will it hurt her to have a baby pull on her fur, or grab for her ears?