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Nail biting - Nail and Distal Digit
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Nail biting - Nail and Distal Digit

Contributors: Shari Lipner MD, PhD, Susan Burgin MD, Bertrand Richert MD, Robert Baran MD
Other Resources UpToDate PubMed


Onychophagia describes a habit of nail biting in which the nails and adjacent skin are chewed. The fingernails are the preferred site, although occasionally the toenails are involved. Patients usually bite the nails on both hands.

Nail-biting behavior can be made worse when the patient is anxious, bored, or working on complex tasks. It improves with social interaction. It may also improve when the behavior is pointed out.

Nail biting often begins in childhood or adolescence, but cases of adult-onset nail biting do occur. Nail-biting behavior typically lasts for approximately 10 years; however, it may persist into adulthood.

Onychophagia may be associated with an underlying psychiatric disease such as obsessive-compulsive disorder, anxiety disorder, impulse control disorder, anorexia nervosa, or bulimia nervosa. There is a partial genetic component of onychophagia, as many nail biters have at least one family member with this habit.

Onychophagia has a negative effect on quality of life. Nails tend to be both very short and uneven. In more severe cases, cuticles are absent or ragged and nail folds are frayed. Splinter hemorrhages are common findings. Sequelae include increased rate of nail plate growth, shortening and disappearance of the nail bed, longitudinal melanonychia, and paronychia. Oral complications are gingival swelling, malocclusion of the teeth, temporomandibular joint syndrome, and infections following oral surgery.

Rare complications are osteomyelitis and herpetic whitlow.

Onychophagia may facilitate the spread of verruca.

Related topic: onychotillomania, trichotillomania


L60.8 – Other nail disorders

37298006 – Nail biting

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Last Reviewed:02/02/2017
Last Updated:07/08/2020
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Patient Information for Nail biting - Nail and Distal Digit
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Contributors: Medical staff writer


Nail biting (onychophagia) is a nervous habit that may begin in childhood and continue into adolescence and adulthood. It ranges from mild to severe. Nail biting almost always involves the fingernails, but in some cases includes toenails.

Who’s At Risk

Nail biting may be associated with compulsive behavior disorders, eating disorders, high anxiety, self-harm, or other personality or psychiatric disorders.

Other possible triggers are boredom, poor self-esteem, and hunger.

Signs & Symptoms

Patients may be observed nail biting as an unconscious, automatic, and unintentional habit. Nail plates may be shortened, ragged, cracked, or bloody, and they may show long ridges, bands, or lines. Extremely shortened nails may be damaged irreversibly, become infected, and spread infection to various organ systems. Teeth and gums may show signs of cracking or damage from nail biting, and jaw problems may be the result of nail biting.

Self-Care Guidelines

Stress relief and relaxation exercises may be helpful. Nail biters may benefit from alternate activities that occupy the hands and mouth.

A number of techniques that have been tried, especially with children, are not effective and sometimes make nail biting worse. Failed techniques include shaming, punishing, and painting nails with a bitter substance.

When to Seek Medical Care

If nails appear damaged or infected, contact your health care provider for assessment and treatment.

You can speak to your health care provider for help with your nail biting if the habit or the appearance of your nails is embarrassing to you.


Your doctor may provide helpful information on relaxation techniques and alternative activities that make nail biting less likely. Your doctor will look for other concurrent disorders that may intensify stress. Common treatments are behavior therapy, medication, or both.
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Nail biting - Nail and Distal Digit
A medical illustration showing key findings of Nail biting : Fingernails, Nail fold erythema and edema, Periungual fingers, Short nail
Clinical image of Nail biting - imageId=1655004. Click to open in gallery.  caption: 'Distal fraying of the nails, enlarged lunulae, and faint longitudinal melanonychia.'
Distal fraying of the nails, enlarged lunulae, and faint longitudinal melanonychia.
Copyright © 2023 VisualDx®. All rights reserved.