Onychophagia, or nail biting, is a pretty common habit, affecting an estimated 30 percent of adults, 45 percent of teens, and 30 percent of children. Though nail biting—which can be caused by stress, anxiety, obsessive compulsive disorder, or just being bored and fidgety—may seem perfectly harmless, it can invite bacteria or fungi infections to enter into the body and blood stream, increasing your chances of contracting a cold or the flu, according to the Mayo Clinic. Not to mention that it can ruin your smile.
How nail biting leads to bacterial and fungal infections
If you’ve ever had a manicure, you’ve no doubt noticed the gunk that the manicurist removes from under your nails. That’s what you can see with the naked eye—so just imagine all the bacteria you can’t see. The most common pathogens lurking under our nails are Staphylococcus, Strep, and Coryneform bacteria, which can enter the body through breaks in our skin or—you guessed it—from ingesting them after biting your nails. If that isn’t enough of a deterrent, just imagine dermatophytic fungi, also known as ringworm, hanging out in our nail tissue as you open mouth and insert finger. Next time the anxiety kicks in, try taking five deep breaths instead.
How nail biting leads to cold and flu
According to the CDC, there are more than 200 cold viruses floating around at any given time. Even though the risk factors for acquiring one include a weakened immune system and/or exposure to someone sick, you can significantly reduce your chances of catching a virus by keeping your hands away from your mouth. Viruses that cause the flu also flourish on your skin, so wash your hands frequently with soap and water (or use an alcohol-based hand sanitizer), and discourage nail biting by chewing gum.
How nail biting can harm your teeth
Nail biting can also damage the teeth and gums. The Academy of General Dentistry has found that nail biting can crack, chip, or wear down the front teeth, and also potentially lead to sore gums and gum tissue damage. Check with your dentist if having a mouth guard can help you to stop biting your nails—or at least minimize some of the damage it can cause. She may also be able to suggest some other techniques to help you quit the habit for good.