Nail biting almost always begins in childhood. It's a behavior often associated with stress or anxiety, but it's likely more complicated than that. For instance, one theory is that it helps some people regulate their emotions — or it feels like it does anyways.
The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, categorizes chronic nail biting as other specified obsessive-compulsive disorder (OCD), classified in the same group as compulsive lip biting, nose picking, and hair pulling (American Psychiatric Association, 2013).
Sometimes, nail biting can be a sign of emotional or mental stress. It tends to show up in people who are nervous, anxious or feeling down. It's a way to cope with these feelings. You may also find yourself doing it when you're bored, hungry or feeling insecure.
In fact, you may have heard how it takes 21 days to break a habit. This figure was popularized by a 1960s book called “The New Psycho Cybernetics” by Maxwell Maltz.
Nail biters are more often male than female after age 10 (10% fewer bite their nails than boys), and individuals with a higher rate of intelligence tend to bite their nails more than those of less intelligence.
Anxiety: Nail biting can be a sign of anxiety or stress. The repetitive behavior seems to help some people cope with challenging emotions. Boredom: Behaviors such as nail biting and hair twirling are more common when you're bored, hungry, or need to keep your hands busy.
While most people assume nail biting has to do with nerves or anxiety, one study is linking this bad habit to a surprising personality trait. According to a study published in the March 2015 issue of Journal of Behavior Therapy and Experimental Psychiatry, nail biters are more likely to be perfectionists.
Once you've managed to stop biting your nails, one of the questions often asked is whether bitten nails can grow back to normal. The bad news is that although fairly uncommon, nail biting can lead to permanently damaged nails. You can cause permanent damage to your nails by biting them over a long period of time.
Additionally, if you swallow the nails, they can do damage to the epithelial lining of your esophagus and stomach. They will not digest, so if they're sharp, they will make their way through your entire body potentially scratching up your digestive tract.
But they do know that it's a habit for a lot of us: about 20 to 30 percent of the population are nail biters, including up to 45 percent of teenagers.
What Is Dermatophagia? Many people bite their nails or occasionally find themselves chewing on a hangnail, but if you find yourself compulsively biting and eating the skin on your hands and fingers, you may have dermatophagia. Dermatophagia is what's known as a body-focused repetitive behavior (BFRB).
Fingernails grow about 3.5 millimeters each month
And toenails grow about 1.5 millimeters per month. Those are the averages for healthy adults. Whether you're getting proper nutrition and how well you take care of your nails can affect the growth rate.
"From chronic nail biting, you can damage the nail matrix (the tissue under the actual nail) and can have permanent nail deformities like ridges," explains Dr. Jaliman.
Nail biting can also transfer pinworms or bacteria buried under the surface of the nail to your mouth. When bitten-off nails are swallowed, stomach problems can develop.
Biting your fingernails or cutting your fingernails too short can give the appearance of a shorter nail bed. This is due to little or no whiteness at the tip. Fungal infections. Your nail bed can also appear shorter if you develop a nail fungal infection.
Similarly, biting your nails might increase the rate of nail growth. While it's not clear exactly how this occurs, researchers theorize that the physical manipulation of a nail through biting stimulates the growth plate of each finger to be more metabolically active, leading to speedier nail formation.
Nail-biting (onychophagia) is a common stress-relieving habit. You may bite your nails in times of stress or excitement, or in times of boredom or inactivity. It can also be a learned behavior from family members.
They report that touching, rubbing or biting skin, nails, and hair prompts a relaxing, trance-like state, which distracts from negative emotions. When bored, body-focused repetitive behaviours can help people feel like they're doing something active, especially those with perfectionistic personality traits.
Behavioral therapy: Therapy can help release the shame and negative emotions that often accompany nail biting. It can also help increase awareness of the triggers and urges you feel. In some cases, habit-reversal training or hypnotherapy are effective.
Your immune system gets hit
It is known that people who usually bite their nails experience the common cold more often than people who do not bite their nails. While continuously infected with a cold can weaken your immune system and leave it open to more dangerous ailments.
Healthy fingernails are smooth, without pits or grooves. They're uniform in color and consistency and free of spots or discoloration. Sometimes fingernails develop harmless vertical ridges that run from the cuticle to the tip of the nail.
Chacon, MD, FAAD, a board-certified dermatologist. “Fingernails tend to grow about 0.7 mm or about 0.03 inches per week,” she says, adding that toenails take about 2-3 times longer to grow.