Dermatophagia

Dermatophagia, from the Ancient Greek for skin and eating, also called dermatodaxia, is a compulsion disorder of gnawing or biting one's own skin, most commonly at the fingers, and the behavior can be either conscious or unconscious. It falls within the category of pica disorders. Those affected typically bite the skin around the nails, leading over time to bleeding and discoloration, and some also bite their finger knuckles, causing pain and bleeding with finger movement. The same term applies in herpetology to amphibians and reptiles eating their own shed skin, but that use does not apply to the human condition, in which repeatedly bitten skin thickens rather than sheds. Contemporary research links the behavior to impulse-control and obsessive-compulsive disorders, and the DSM-5 classifies dermatophagia under other specified obsessive-compulsive related disorders, with the specifier body-focused repetitive behavior.