Anxiety and obsessive compulsive disorder (OCD), says a study published in the Journal of National Center for Biotechnology Information, are the reasons 14 percent of the population bite their nails.
"Nail biting is a way to ease anxiety," explains Dr. Joy-Alvi R. Arañas, psychologist at Pathway Counseling and Assessment Center in Bacoor City, Cavite. "It is also a sign of boredom or stress. It can be classified as an impulse control problem or a symptom of an obsessive compulsive disorder."
Individuals who suffer from OCD tend to be trapped in a pattern of repetitive behaviors that are senseless and distressing, but extremely difficult to overcome.
"You will know if it's already severe if there is a recurrent and persistent urge to bite the nails," Arañas says. "The behavior becomes repetitive and sometimes the individual may have difficulty controlling his actions. It can be a behavioral manifestation of much serious psychological disorder."
Dermatologist Dr. Rochelle Torgerson meanwhile says in a Huffington Post interview that the habit may also lead to colds and other illnesses because it encourages the spread of germs from the nails to the lips and mouth.
"The more open skin you have, the more you're going to spread [the virus]," she warns.
The pressure of chomping on and around your nails also creates microscopic breaks in the epidermis. When these happen, pathogens—including various warts-causing human papillomavirus (HPV) strains—can take hold, lnitiating spread of warts on your fingertips and around your neck.
Nail biting can also be harmful for your dental health. Margielyn Jorgio, DMD, says people who bite their nails could crack, chip, or wear down their front teeth due to the stress of biting. "Nahi-hit repeatedly and forcefully 'yung upper and lower incisors kaya it would cause fracture on the edge of the teeth," says the Pangasinan-based dentist.
It would be much worse if the person who does this wears braces. "Those who wear braces put their teeth at even greater risk for root resorption (a shortening of the roots) or tooth loss since the braces already put increased pressure on the teeth."
This can also delay your orthodontic treatment, meaning you'd need to wear your braces for a longer time than you would if you didn't bite your nails.
Nail biting is also incredibly unsanitary. "Our nails harbor all sorts of germs and bacteria so pag nag-nail bite, nai-introduce 'yung bacteria sa oral cavity and it may lead to gum disease," Jorgio noted.
Margaret E. Parsons, a member of the American Academy of Dermatology, says the best thing to do is either keep your nails trimmed short, identify your triggers, and try to gradually stop biting your nails.
"If you've repeatedly tried to quit and the problem persists, consult a doctor. If you bite your nails and develop a skin or nail infection, consult a board-certified dermatologist," she says.