The unsightly appearance of chewed-to-the-quick fingernails hasn’t been enough to deter you from nibbling? Perhaps learning that biting your nails promotes the spread of warts and can even increase skin cancer risk will inspire you to break the habit.

Neal B. Schultz, MD, an assistant clinical professor of dermatology at Mount Sinai School of Medicine, explained that even if you don’t see any blood, the pressure of chomping on and around your nails creates microscopic breaks in the epidermis (the protective outer layer of skin). When that barrier is broken, pathogens—including the various human papillomavirus (HPV) strains that cause warts—can take hold. At that point, nail-biting can cause warts to spread on your fingertips and around your nails. “The lips and mouth do a great job of transferring HPV from one spot to another,” Dr. Schultz said. Worse, because certain HPV strains can cause cancer, nail-biting also increases your risk of developing squamous cell cancer on your fingers.

As a reformed nail-biter himself, Dr. Schultz sympathizes with how hard it can be to break the habit. Any or all of the following strategies can help…

  • Coat your nails with an over-the-counter product that creates an unpleasant taste or burning sensation in the mouth. This provides negative reinforcement to discourage nail-biting. Dr. Schultz recommended Mavala Stop.
  • It is easier to replace a harmful habit with a harmless one than it is to break a bad habit altogether. So when you feel the urge to nibble, instead squeeze each nail in succession with the thumb and fingers of the opposite hand for a count of 10, Dr. Schultz suggested, continuing until the impulse passes.
  • Consult a psychologist trained in cognitive behavioral therapy. Referrals: Association for Behavioral and Cognitive Therapies. The behavior modification techniques you learn will help you eliminate nail-biting and the associated HPV risks.