Hello!
Your mother and you should be asking some very serious questions of yourselves and the doctors...Warning: this could get long...
1) what kind of doctor has your mother been seeing besides the derm?
2) what was the ana titer? (a slightly positive titer would be 1:160)
3) did they test her sedrate? C reactive protein?
4) what disfigured her face? The rash? Or, did she have engorged lymph nodes? Or something else?
5) what is her steroid dosage and for how long? Ie...How long has she been on the 40mg? And was she taking any before being on the 40 mg?
6) what other seemingly non-worrisome issues does she have? Stomach aches, diarrhea, headaches, joint pain (classifed with pain , low grade fevers, etc?
7) has she had a recent urinalysis? What were the results?

do you have a copy of all her test results since this "flare" began?
9) tests they should be doing? Well, I would first suggest that she go to a rheumatologist. Remember a positive ana does not mean lupus...And there are other autoimmune diseases that cause a positive ana.
10) did they check her double stranded dna? Lupus anticoagulant (which by the way you do not have to have lupus to have), etc.
Go see a rheumatologist. Keep a diary of your mother's symptoms and take that to the rheumatologist. Get all her lab results and doctor's notes and take those too.
I hope this is helpful and if you need anymore help...Go ahead and ask. I'll answer if I can...
Wishing you both the best,
ladybrannon