Body-focused repetitive behavior

human habit

oral compulsive habit

mental disorder involving compulsive skin-picking

Trichophagia is a form of disordered eating in which persons with the disorder suck on, chew, swallow, or otherwise eat hair. The term is derived from ancient Greek θρίξ, ("hair") and φαγεῖν, ("to eat"). Tricho- refers only to the chewing of hair, whereas tricho- is ingestion of hair, but many texts refer to both habits as just trichophagia. It is considered a chronic psychiatric disorder of impulse control. Trichophagia belongs to a subset of pica disorders and is often associated with trichotillomania, the compulsive pulling out of ones own hair. People with trichotillomania often also have

Dermatophagia () or dermatodaxia () 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 and it is considered to be a type of pica. Those affected with dermatophagia 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.

mental and behaviour disorders including skin picking and hair pulling

Onychotillomania is a compulsive behavior in which a person picks constantly at the nails or tries to tear them off. It is not the same as onychophagia, where the nails are bitten or chewed, or dermatillomania, where skin is bitten or scratched. Onychotillomania can be categorized as a body-focused repetitive behavior in the DSM-5 and is a form of skin picking, also known as excoriation disorder.