As I was reading through your post I kept thinking "adrenal glands." So I wasn't surprised to read the last line.
Nor should it be any surprise that the wiki entry contains this sentence:
"[Discoid] eczema can also be worsened by stress and caffeine, which dehydrates the body and thus the skin."
They say this because stress and caffeine are hard on the adrenals, whose number one job is "fluid balance" in the body.
So I recommend you pursue the adrenal angle. I wouldn't focus on the DISCOID part of it so much--the distinction seems mostly to be the shape of the lesions.