Author: Brian Wu, MD candidate, Keck School of Medicine, Los Angeles, USA. DermNet New Zealand Editor in Chief: Hon A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand. December 2016.

What is onychophagia?

Onychophagia is the clinical name for fingernail biting. It is a common stress-related or nervous habit in children and adults. It involves biting off the nail plate, and sometimes the soft tissues of the nail bed and the cuticle as well. Onychophagia is also known as onychotillomania, which includes the habit of picking or otherwise manipulating the nails.

Some researchers believe that nail biting is a result of a delay or dysfunction in the oral stage of psychological development.

What psychosocial and/or physical problems does onychophagia cause?

Onychophagia can cause distress, emotional tension or social embarrassment. It is associated with other habit disorders, including trichotillomania and compulsive skin picking.

While it does not cause them, onychophagia is associated with a variety of psychiatric disorders, including:

It is also important to note that nail biting can also cause physical problems, including:

Assessing the impact of onychophagia

While there is no assessment tool specific to onychophagia itself, some research has centred on the Strengths and Difficulties Questionnaire. This mental health tool is able to assess a variety of emotional and behaviour problems, including inattention and hyperactive behaviour, emotional symptoms, conduct problems, and prosocial behaviour. When dealing with onychophagia, it can be useful to consider the issues covered in this questionnaire as a way to look for relationships/associations that may influence the individual’s nail-biting habit.

Nail biting and dysmorphia

If left untreated, severe onychophagia can lead to dysmorphic dental problems, including:

These problems can affect the individual’s physical appearance, but this can be avoided if the nail-biting habit is broken early.

How is onychophagia treated?

The treatment for onychophagia depends on the severity of the nail-biting habit:

Related information

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