Picking behaviors target not only the skin but also the nails and cuticles of the hands and feet. Known medically as onychophagia, biting and picking at the nails and cuticles is a body-focused repetitive behavior resulting in repeated injuries and dental problems.
How common is this?
Nail-biting is fairly common, with research suggesting that approximately 20-30% of the general population struggles with it. The age group it affects the most appears to be middle childhood to young adolescence with estimates showing it affects 20.1-33% of children aged 7-10 and 45% of children between age 10 and puberty. Another age group with high prevalence rates is young adults with 21.5% of people between 17 and 35 experience it. Finally, the epidemiological trends suggest it affects females more often than males in every age group.
Biting and picking behaviors usually start early in life. It most commonly begins in childhood or adolescence but can start at any age. One research study found that of 339 people who bit their nails, the average age of discontinuing was 13-14 years old with most engaging in the behavior for an average of 10 years. Those same participants reported biting their nails daily or almost daily and biting on both hands.
What causes it?
Similar to other body-focused repetitive behaviors, there is no known cause for the disorder. Some researchers affiliate nail-biting and cuticle picking with obsessive-compulsive disorders, while others attribute it to anxiety. There is some evidence, however, of a genetic component. A survey of 743 parents and their school-age children found that 36.8% of children with nail-biting problems also had a family member who bit their nails. Twin studies, which provide great indications of genetic links, also suggest there is a genetic link.
Bad habit or disorder?
As with other body-focused repetitive behaviors, nail-biting and cuticle picking vary in behavioral presentation. On the one hand, mild nail-biting may occur as an unconscious automatic behavior that relieves anxiety while a person may engage in biting and picking behaviors with full awareness and intent.
Some people may experience this phenomenon as a bad habit that they engage in occasionally but do not consider it disordered behavior. In others, the behaviors cause significant damage to the nails and skin, some experience dental problems or get infections because of the behavior. When a behavior causes impairment and injury, then it may be considered a disorder.
Onychophagia is not a distinct diagnosis in the DSM-V, which is the psychiatric diagnostic manual, but it falls with the spectrum of obsessive-compulsive disorders and skin-picking disorder. In medical diagnostics, it falls under the category of “other behavioral and emotional disorders with onset usually occurring in childhood and adolescence.” According to both diagnostics, several things need to occur in order to classify nail-biting and cuticle picking as a disorder:
- Behavior results in repeated injury
- Multiple failed attempts to stop the behavior
- Negatively affects social, occupational, and relational life
Nail-biting and cuticle picking do not always occur alone, and they often associate with the following conditions:
- Obsessive-compulsive disorder
- Other body-focused repetitive behaviors
The medical research literature notes several physical complications of nail-biting and cuticle picking.
- Increased growth of the nail plate
- Progressive nail shortening
- Inflammation, pain, redness
- Blackening or darkening of the nail
- Bacterial and fungal infections of the nails
- Severe infections can lead to osteomyelitis or bone infections
- Increase susceptibility to lesions caused by the herpes virus
- Facilitates spreading of warts
Oral and Dental Complications
The hands carry bacteria and other not-so-healthy things that end up in the mouth. The following are a list of oral and dental problems that often result from nail-biting.
- Increased bacteria in the mouth including MRSE
- Swelling, redness, bleeding, and inflammation in the gums
- Abscesses in the gums
- Crowding of the incisor teeth
- Pain in the jaw from repeat muscle activity
- Croup-like cough from breathing in foreign material
Impact on quality of life
For people with disordered nail-biting or cuticle picking, the behaviors interfere with the quality of life in several respects.
- Because so much of daily activity involves the hands, a person who bites nails stops activities to engage in the behavior. Sometimes this results in frequent starting and stopping of activities and disrupting others.
- The inability to control the behaviors often leads people to believe they are weak, which leads to embarrassment, guilt, and shame.
- For those who experience physical complications due to nail-biting, often the outward appearance of infection or disease creates personal discomfort and unwanted questions or stigma from others.
- People who work in public professions such as healthcare, food service, or another service job where displaying the hands to strangers is common may also experience adverse reactions from employers, coworkers, and customers.
What treatment options are available?
Treatment for disordered nail-biting and cuticle picking depends on the level of impairment, the types of complications, and the type of behavior. Therefore, a full assessment is a valuable tool for determining treatment options. A medical assessment is important to determine the effects of complications while a psychological or mental health assessment can narrow behavioral treatments to an effective method.
There are multiple treatment options available, including behavioral, pharmacological, and mechanical.
The goal of behavioral treatment is to unlearn habits and create healthier behaviors, which is why assessment is crucial. Treatment for unfocused nail-biting and cuticle picking will focus on improving self-awareness and identifying triggers for the behavior. Once those are identified, therapies such as habit reversal training can help a person develop other behaviors. Cognitive-behavioral therapy and acceptance and commitment therapy are other non-pharmacological treatments available through mental health providers.
There is not much available for pharmacological treatment of onychophagia. For those who bite or pick in response to anxiety, sometimes anti-anxiety medications can ease the conditions leading to the behaviors. The only pharmacological treatment that indicated some effectiveness was N-acetyl cysteine (NAC), which has been tested with other body-focused repetitive behaviors. However, in the randomized, double-blind placebo-controlled trial, which means it was a thorough, well-done study, showed that NAC was no more effective than a placebo. Therefore, use caution when considering pharmacological treatments and only after a thorough assessment.
Mechanical therapies create a barrier between the hands and the mouth, or the use of a tool to increase awareness of nail-biting and cuticle picking. For people who bite their nails, object manipulation, or doing something with the hands such as squeezing a stress ball, can distract and occupy the hands to prevent biting. Using bitter-tasting lacquer can be used as an aversive therapy, which creates a horrible taste when someone put their hands in their mouth. Habit awareness wearables such as the Keen from HabitAware helps increase awareness of biting behaviors and can be set to alert the wearer when the hands move into position to bite. Another unique approach to mechanical treatment involves implantation of a fixed oral appliance place by a dentist that makes nail-biting difficult and unpleasant, although this intervention may not be readily available.
Although some people grow out of the compulsion to bite nails or pick cuticles, the many treatment options available can help improve mental and physical health as well as the quality of life.
References used in this article:
Evidence-based psychosocial treatments for pediatric BFRBs https://www.tandfonline.com/doi/full/10.1080/15374416.2015.1055860?src=recsys
Onychophagia: A nail-biting conundrum for physicians https://www.tandfonline.com/doi/full/10.1080/09546634.2016.1200711
Onychophagia associated with impaired quality of life. https://www.medicaljournals.se/acta/content_files/files/pdf/94/6/4127.pdf
New approach to managing onychophagia https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5141299/