<unk>  usually leads to harmful effects to the fingers, like infections. These consequences are directly derived from the physical damage of<unk>  or from the hands becoming an infection vector. Moreover, it can also have a social impact, for example social withdrawal and avoiding handshakes. The ten fingernails are usually equally bitten to approximately the same degree. Often, the adjacent skin is bitten off, too, which is called perionychophagia, a special case of dermatophagia.<unk> <unk> s can lead to broken skin on the cuticle. When cuticles are improperly removed, they are susceptible to microbial and viral infections such as paronychia. Saliva may then redden and infect the skin. In rare cases, fingernails may become severely deformed after years of<unk>  due to the destruction of the<unk>  bed.<unk>  may have an association with oral problems, such as gingival injury, and malocclusion of the anterior teeth. It can also transfer pinworms or bacteria buried under the surface of the<unk>  from the anus region to the mouth. If the bitten-off<unk> s are swallowed, stomach problems can occasionally develop.<unk>  can be a source of guilt and shame feelings in the<unk>  biter, a reduced quality of life, and increased stigmatization in the inner family circles or at a more societal level. Related disorders Other body-focused repetitive behaviors include excoriation disorder (skin picking), dermatophagia (skin<unk> , and trichotillomania (the urge to pull out hair), and all of them tend to coexist with<unk> . As an oral parafunctional activity, it is also associated with bruxism (tooth clenching and grinding), and other habits such as pen chewing and cheek<unk> . In children<unk>  most typically co-occurs with attention deficit hyperactivity disorder (75% of<unk>  cases in a study), and other psychiatric disorders including oppositional defiant disorder (36%) and separation anxiety disorder (21%). It is also more common among children and adolescents with obsessive–compulsive disorder.<unk>  appeared in a study to be more common in men with eating disorders than in those without them.
Nail biting
Spider bite
Cat bite
Dog bite
Hand washing
Animal bite
Insect bites and stings
Needlestick injury