There have been many different theories regarding the causes of<unk>  including biological and environmental factors. A common hypothesis is that<unk>  is often a coping mechanism to deal with elevated levels of turmoil, arousal, or stress within the individual and that the individual has an impaired stress response. A review of behavioral studies found support in this hypothesis in that skin-picking appears to be maintained by automatic reinforcement within the individual. In contrast to neurological theories, there are some psychologists who believe that picking behavior can be a result of repressed rage felt toward authoritarian parents. A similar theory holds that overbearing parents can cause the behavior to develop in their children. Neurological There is limited knowledge regarding the neurobiology that drives<unk> , and there have been few neuroimaging studies of those with<unk> . Those individuals that have<unk>  along with other diagnosed conditions report differing motivations for their picking. Those with both OCD and<unk>  report that they will pick their skin due to perceived contamination of the skin, while those with both body dysmorphic disorder (BDD) and<unk>  reportedly pick to fix perceived imperfections in the skin. Studies have shown a linkage between dopamine and the urge to pick. Drugs such as cocaine and methamphetamine, which increase the pharmacological effects of dopamine, have been shown to cause uncontrollable picking in users. These drugs can create the sensation of formication, which feels like something is crawling on or under the skin. Thus,<unk>  could result from a dysfunction in the dopamine reward functions. There may be another neurological explanation for<unk> : individuals with the condition have less motor-inhibitory control, but show no sign of a difference in cognitive flexibility when compared to individuals without the condition. Motor-inhibitory control is a function of the right-lateralized frontostriatal circuit, which includes the right inferior frontal and bilateral anterior cingulate cortices. The impairment of motor-inhibitory control is similar to the neurological conditions of those who have problems suppressing inappropriate behaviors, such as using methamphetamine. Genetic components There is significant evidence to suggest that skin picking disorders are due to inherited traits or genes. There have been multiple small studies with similar conclusions in regards to the SAPAP3 gene. Excessive grooming by mice has been observed by researchers after the deletion of the SAPAP3 gene. This observation led researchers to study the effects of the SAPAP3 gene on patients with trichotillomania—a disorder marked by the same behaviors directed at one's own head and body hair. This study revealed a significant link between a single nucleotide polymorphism (SNP) within the SAPAP3 gene and trichotillomania.
Excoriation disorder
Trichotillomania
Necrospermia
Papulosquamous disorder
Adermatoglyphia
Oral galvanism
Pellagra
Trichostasis spinulosa