This reminds me a lot of the Shifters in Kyla's book, Caste. I can see this look just as she is about to shift (into a dragon of course). Her skin pales, lips slightly open, eyes already transitioning into the cat eyes characteristic of a shifter. Love how this teased my imagination!
Said to be a canibalistic disease of the heart/mind in which the affected person consumes the lives of other humans and things with no regard for the natural balance of things… equated to greed and a deep fear of lack.