When I went off my medications for quite awhile, my skin became all over very dark bronze eventually developing an orange hue - weird! This became more obvious the longer I was off  corticosteroid medications, as the ACTH level rose higher.

Initially the pigmentation was, as you say, on the knuckles, palm creases, scars etc. The interesting thing though is, that three years after resuming my medications I still have significant patches of pigmentation on my forearms. However, the all-over tanned look disappeared probably within a couple of months of regaining control of my levels.