Self Cannibalism

Awful as it may sound, for the past 18 years I have worked my way through the skin-picker's menu. Starting with my fingernails from an early age, I began to pick the skin from the bottoms of my feet and around my finger and toe nails with clippers when I was about nine. Now, while i find myself living alone, I am still eating the skin around my fingertips and from my feet and ripping off my nails and occasionally i search my back and head for more delicacies to consume. I commence to eating, and do not exactly know why. Scabs are the same way. I have to keep scratching and ripping it off and sometimes i get agitated because a new layer hasn't arrived yet fresh for me to pick and the blood from the scabs...all of it just goes down the throat without a second thought. If anyone else is a skin-picker, or a compulsive nail-biter, I would like to know....Is this a form of anxiety or OCD? i have no clue either.