Many of us develop bad habits as kids, like thumb sucking, fidgeting, hair twirling and nail biting. While we tend to grow out of most of them, some of them can stay with us into adulthood. Nail biting is in fact the most common habit disorder in adults. Usually triggered by boredom, stress or anxiety, it has several unhealthy side effects, apart from just grubby looking fingernails.

Bacterial infections

Even if you wash your hands often, you may not necessarily clean under your nails. Studies have found that your fingernails are usually twice as dirty as your fingers, and that they tend to have a lot of bacteria hiding under them. When you bite your nails, this bacteria gets transferred to your mouth and into your body, causing bacterial infections.

Nail infections

Biting your nails leads to several tiny tears and abrasions in the skin around your nails, through which bacteria, yeast and other microorganisms can get under your skin. Frequent nail biters are susceptible to paronychia, which is a painful skin infection that develops around the nails.


Human papillomavirus (HPV) is another infection that nail biters are susceptible to. This condition is usually faced only by chronic nail biters, but the effects are not pretty. It results in warts around your fingernails, and then when you bite your nails they can spread to your mouth and lips too.

Dental problems

Nail biting affects not only your nails but your teeth too. It can cause your teeth to shift from their correct position, wear out early or become weaker over time. It can also spoil your dental occlusion, which is the alignment of your upper and lower teeth when they come together, whenever you close your mouth.

Occupied hands

This is a problem faced by people who bite their nails out of stress, where if they are given a task to do then they cannot complete it properly because they are biting their nails on one or both hands. This makes it difficult for them to do things, slowing them down and reducing their efficiency.

Poor quality of life

A study found that 20 to 30 percent of the population tends to bite their nails, and that those who do have a lower quality of life than those who don’t. Some of the causes of this effect are the suffering faced due to nail biting, the stress of trying to resist nail biting and problems caused due to eating bitten nails.