7 Dangers of Biting Your Fingernails

7 Dangers of Biting Your Fingernails

At one time or another you must have found yourself biting your fingernails. Short of a lazy grooming attempt most people grow out of this while others, maybe you, have turned it into a habit.

If you are continually chomping on your cuticles you may want to think about weaning yourself off this fixation as it can be compromising your health. These 7 dangers of biting your fingernails, also known as onychophagia, show how, what may seem like a harmless activity could be a slowly accumulating physical threat.

Eating Germs

An entire host of germs can thrive under your fingernails so when you put them in your mouth you are inviting these pesky microbes into your system.

According to Michael Shapiro, M.D., medical director and founder of Vanguard Dermatology in New York City.

“Your fingernails are almost twice as dirty as your fingers. Bacteria often gets stuck under the nails, and can then be transferred to the mouth, causing infections of the gums and throat.”


The human papilloma virus (HPV) is a dangerous sexually transmitted disease that could lead to cancer. What many don’t know is that this virus can attach itself under your fingernails during sex and may be transmitted to your mouth when you bite them.

HPV also presents as tiny warts on your fingers which can easily be passed to your mouth causing warts in and around the area as well as the throat which some believe may lead to oropharyngeal cancer.

Compromised Smile

Constant biting of nail enamel could take its toll on your teeth.

Dr. Shapiro comments,

“It can interfere with proper dental occlusion, or the manner in which your upper and lower teeth come together when you close your mouth,…Plus, your teeth may shift out of their proper position, become misshapen, wear down prematurely, or become weakened over time.”

The Huffington Post reports that,

“According to the Academy of General Dentistry (AGD), nail biting can result in up to $4,000 in additional dental bills over one lifetime.”

E. Coli and Salmonella

The germs that embed themselves under your nails may cause systemic upheaval that you may never associate with your habit and keep getting as a result.

E. Coli and Salmonella are two diseases that can live under your nails for some time. These two strains could result in very nasty gastrointestinal challenges, another good reason not to bite your nails.


The more you bite your nails the more chances you have to experience nail infections. As you tear open tiny holes in your skin and then transfer bacteria from your mouth into them there is a good probability that your nail bed and surrounding finger tissue could become infected.

Now many people who bite their nails may report that they never experienced this, however, most do not realize that these infections can be microscopic. As a result, your body is constantly fighting these microscopic infections which could take away your immune system’s ability to fight other, more important, infections.

Some studies suggest that biting your nails strengthens your immune system but others report that it puts an unnecessary strain on the rest of your body which could result in peripheral illness.

Cognitive Disorder

As biting your nails continues to put you in harm’s way when it comes to your physical state, it could also be masking a mental disorder that should be addressed.

This chronic habit could be obsessive compulsive disorder (OCD). In 2012, the American Psychiatric Association decided to re-classify nail biting as a form of OCD.

This condition causes many stressful responses by the brain such as constant hand washing, repetitive counting and persistent cleaning or organizing. Nail biting may replace these behaviors but the mental disorder remains and, if not addressed, could manifest into more serious, detrimental behavior in the future.

In a study presented by The Journal of Behavior Therapy and Experimental Psychiatry (3/15) it was concluded that,

“The BFRB [Body-focused repetitive behaviors such as hair-pulling, skin-picking, and nail-biting] group presented significantly higher scores on maladaptive planning style, and maladaptive planning style was significantly correlated with difficulties with ER [emotional regulation].”

The Common Cold and Friends

Biting your fingernails could make you more susceptible to getting continued bouts of pathological strains which lead to many forms of experiencing a cold.

The common cold may not seem like such a big danger but if you are continually re-infecting yourself you may be setting yourself up for more serious health challenges down the line.

Kristine Arthur, M.D., an internist at Orange Coast Memorial Medical Center in Fountain Valley, CA comments,

“Think of every single thing you touch during your day, from doorknobs to toilets,…Germs can live on these surfaces for hours, so when you stick your hands in your mouth, you’re exposing yourself to cold and flu viruses, or even serious illnesses like hepatitis.”

These 7 dangers of biting your fingernails should make you re-think your habit. There are many ways to teach yourself to stop which include putting foul tasting substances on your nails such as vinegar, hot sauce, or commercially available bitter tasting polishes; wrapping your nails in band-aids; or keeping a journal to identify your triggers such as boredom or stress and then recognizing these so you can avoid them.