<unk>  (from Ancient Greek δέρμα - skin - and φαγεία - eating) is a compulsion disorder of gnawing or biting one's own skin, most commonly at the fingers. This action can either be conscious or unconscious. Those affected with<unk>  typically bite the skin around the nails, leading to bleeding and discoloration over time. Some people also bite on their skin on their finger knuckles which can lead to pain and bleeding just by moving their fingers. In herpetology,<unk>  is used to correctly describe the act in which amphibians and reptiles eat the skin they shed, but this is not what occurs in humans. Those diagnosed with this disorder do not develop wounds on the bitten areas of their hands or lose any skin. Instead, they experience a thickening of the skin being repeatedly bitten. Contemporary research suggests a link between impulse-control disorders and obsessive–compulsive disorders, and this was addressed in the DSM-5 when<unk>  and other related disorders were classified as 'other specified obsessive-compulsive related disorders' and are given the specification of body focused repetitive behavior. Further information on OCD, other anxiety disorders,<unk>  and other related body focused repetitive behaviors can be found in the DSM-5.
Dermatophagia
Aerophagia
Burning mouth syndrome
Oral allergy syndrome
Geophagia
Soteria 
Pellagra
Arrhinia