How biting your nails can cause infections

Biting one’s nails may be a coping mechanism for stress, nervousness and boredom.
Biting one’s nails may be a coping mechanism for stress, nervousness and boredom.

Every now and then you may find yourself nibbling at your nails. You might be doing it subconsciously while working or watching television or you might be a conscious nail-biter struggling to kick the habit.

According to studies, approximately 20 to 30% of people are regular nail-biters. Medically referred to as onychophagia, biting one’s nails is seen as a coping mechanism for things like stress, nervousness or boredom.

The American Academy of Dermatology notes that onychophagia can also be triggered by physical factors like hangnails, chipped nails or chipped nail polish.

However, biting you nails is not just an innocent coping mechanism – it can unfortunately also transport nasty bacteria from your nails to your mouth or create an opening for bacteria and fungi to infect your nail bed.

Nail-biting situation 

In an interview with Time magazine, nail disorder expert Dr Richard Scher notes that the area underneath your nails is a perfect breeding ground for bacteria such as salmonella and E. coli. In fact, a study by researchers at the Atatürk University in Turkey found that 76% of people who bit their nails had E. coli in their saliva, compared to 26% of non-nail-biters.

Ingesting bacteria like E. coli, salmonella and the like can make you really sick. Common symptoms include diarrhoea, vomiting, abdominal cramps and fever. 

Chomping away at your nails and the surrounding skin opens the area to infections like paronychia. Paronychia is a skin infection that causes the infected area to swell, followed by some redness and mild pain. Anyone is susceptible to this infection, which can be caused by both fungi and bacteria. Symptoms can worsen rapidly when caused by bacteria.


Paronychia comes in two forms, acute paronychia and chronic paronychia. Acute paronychia does not last long, but can cause abscesses to form around the nail. Chronic paronychia can last for several weeks at a time and can return. Chronic paronychia can leave the nail feeling hard and slightly deformed. In worse case scenarios the nail can separate from the finger.

If you suffer from diabetes, paronychia can be particularly dangerous. The infection can spread from your fingernails to body tissues and bones. In the worst case scenarios the infection can result in the loss of fingers and toes.

You can prevent infection by refraining from nail-biting, making use of clean nail clippers and keeping your nail area clean. Make sure that your nails are always neatly trimmed to avoid hangnails. You can also purchase over-the-counter products that discourage you from biting your nails.

You can treat infected nails by regularly soaking the infected areas in warm water. Should the situation not improve, it is advisable to see a doctor.

Image credit: iStock

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