Dr. Decipher: Nail Biting A Hard Habit to Break

By Dr. John Janousek, M.D. Monday, July 19, 2010

Every time I see a particular friend’s teenage son he has a finger stuck in his mouth nibbling at the nail, then examining  it and nibbling again and again. His nails are short and irregular which make his fingers appear painful and stubby. Even when his father tells him to stop he continues, seemingly unable to control it.

What kind of disorder is nail biting?
The medical name is onychophagia, and it is a compulsive oral habit.

Freud would call it oral fixation, but it is now though to be more of an obsessive compulsive disorder. There is a stress relieving aspect and seems to run in families. Some nail biters have a lot of anxiety, and in others it seems to be a form of exaggerated grooming. It is thought to be in the same category (impulse control disorders) as nail picking, nose picking, thumb sucking, hair pulling (trichotillomania) or twisting, tooth grinding, and skin or scab picking (psychogenic excoriation). Interestingly, nail biters constantly examine their nails and cuticles for the slightest imperfection then bite loose ends, which paradoxically makes them look even worse.

How common is nail biting?
It is very common and the prevalence increases through the teenage years, then decreases thereafter. About 30 percent of children, and 45 percent of teens bite their nails at some time, and it is more common in boys. The incidence greatly drops after about age 30 but the habit persists in about 10-20 percent of adults. Surprisingly, around 15 percent of people bite their toenails (now that’s flexibility).

Are there any health risks?
Bacteria is introduced both into the mouth from the fingers and conversely, to the fingers from the mouth. Finger infections include cellulitis and paronychia (a pus collection at the nail fold area). Aphthous ulcers (canker sores) of the mouth also occur. Viral infections such as herpes simplex can be transmitted causing a rash on the finger called whitlow.

What about the social effects?
The finger disfigurement may cause lower self esteem, and result in poorer social interactions, and can even affect employability. Nail biters may hide their hands and keep them in their pockets. This habit may be seen as a sign of weakness, an inability to control oneself.

Okay, how do you stop?
This requires behavior modification and aversion therapy. Some tips:

1. Note and target the specific times and situations where the most biting occurs such as riding in a car or studying.
2. Keep nails trimmed, get a manicure, and use polish.
3. Substitute a squeeze ball, worry stone, or silly putty to use at target times. (Habit reversal training).
4. Use bitter or pepper polish such as Control-It or Thum as a reminder to stop.
5. Wear gloves at target times, children who bite their toenails can wear pajamas with feet.
6. Stress reduction techniques.
7. Wear mouthpiece.
8. A last option is a medication such as Prozac (Selective Serotonin Reuptake Inhibitors-SSRIs).

Do you have any tips for quitting nail biting or other impulse control disorders? Are there stories you would like to share?