What Is Nail Infection?


Paronychia is the medical name for nail infection. As the name suggests, nail infection can be characterized as the inflammation and infection of the skin around the nail, usually the fingernail folds. The part commonly called the nail is actually the nail plate. The nail plate itself is made of keratin and doesn’t actually get inflamed on its own. The part that actually gets infected or inflamed is the skin around the nail plate.1 2

Paronychia is a very common condition that is caused by microorganisms, usually bacteria or fungi. Although the cause of the inflammation itself is microorganisms, they usually find their way to the fingers through poor care of the area. Activities such as nail biting, improper nail care, smoking, wearing improper footwear, and maintaining poor hygiene of feet and hands make it easier for these microorganisms to play their part in nail infections.2,3

Certain occupations that work with their hands are also at increased risk of developing nail infections. People who work with water and detergents regularly, such as baristas, bartenders, cleaner, etc., and people who use their hands for manual labor such as fishermen, carpenters, builders, nail salon workers, and beauticians have an increased chance of developing paronychia.2,4

There are also conditions that may  accompany paronychiae, such as iron deficiency anemia, thyroid diseases, diabetes, heart conditions, liver conditions, and lung conditions.3

For most cases the treatment of nail infection is quite simple and will include topical treatment such as cleaning the area and medications such as topical or oral antibiotics. Proper hygiene of the feet and the hands are the first line defense against developing paronychia.2,3

Causes of nail infection

The most common type of microorganism behind paronychia is bacteria, specifically Staphylococcus Aureus.(S. aureus) is what is known as an opportunistic bacteria, in normal conditions it is part of the human microbial flora and does not negatively affect us. But when the integrity of the skin is compromised, like when the skin around the nail is damaged due to finger biting, it finds its way into the damaged area, colonizing at the affected area and releasing toxins that cause inflammation. This type of paronychia is usually the acute (sudden onset) kind.2,4,5

Yeast (fungal) infections on the other hand are usually the cause of chronic paronychia. This kind of paronychia usually develops over time and is more persistent. With yeast infection of the nail, there is no pus. Fungal paronychia may also be associated with athlete's foot, which is a fungal infection underneath or between the toes. Other types of microbes such as viruses may also cause paronychia but they are less common.2

Diabetes is also an important cause of chronic paronychia because of its long-term complication of foot ulcers.4,6 Diabetes and its complications are a major topic on their own and further reading on it can be made at Klarity Health Library.

Certain medications such as immunosuppressants or steroids may also cause paronychia.4

Signs and symptoms of nail infection

Most common signs of paronychia are painful redness and swelling on the nail fold. 

There may also be abscess buildup or leak depending on the cause but this does not present in all cases.2,4

Management and treatment for nail infection

In most cases the treatment of paronychia is straightforward. Depending on the presentation of the case, acute paronychia is either treated with the incision and drainage of the abscess and/or antibiotics. In some cases, if the abscess is not big enough, treatment will include soaking the affected finger in clean warm water multiple times a day and antibiotic treatment. There is no proven benefit for using either topical or oral antibiotics so your physician may prescribe either. Further treatment with stronger antibiotics may be needed if the inflammation is persistent, because of underlying health conditions such as diabetes or anything that may cause immunosuppression.2,6


When should I see a doctor

You should see a doctor if the skin around the nails is red, swollen, and warm, which are the signs of infection or ingrown toenails. You should also contact a GP if your finger or nail has changed shape and/or color, or if your nail has fallen off.3

How is nail infection diagnosed

Diagnosis of paronychia will be made by a medical practitioner. Your visit with the doctor will include history taking which will include questions about your daily life and health in general, as well as questions about your hand or foot care routine. There may also be a physical evaluation of the affected area which will reveal swollen and tender nail fold. There shouldn't be a need for laboratory testing or imaging unless your physician thinks there might be an underlying condition that requires further testing. 2,4

There are a few conditions (discussed below) that present similarly to paronychia which your physician will eliminate before reaching the diagnosis: 

  • Cellulitis is the infection of the deep skin tissue. Because both cellulitis and paronychia are skin infections, they can present similarly4
  • Felon is another infection that affects the fingers. It is the skin infection of the touching surface of the finger (known as digital pulp space)3,4
  • Herpetic whitlow is a viral infection that affects the tips of the fingers. It presents a little differently compared to paronychia which will include a burning sensation before the infection is visible. The most important difference is that herpetic whitlow treatment will not include drainage of the abscess as opposed to felon or paronychia as this will cause a secondary infection3,4
  • Fungal infection of the nail known as onychomycosis may also be confused with paronychia. The most important difference is that this type of infection will cause white-yellow discoloration of the skin4
  • Nail psoriasis may also present similarly to paronychia. Psoriasis is a skin condition that causes flaky patches. If these flaky patches form underneath the nails, they may present similar to paronychia4,7
  • Squamous cell carcinoma, which typically is a type of skin cancer, may also present as paronychia if it affects the nail bed4

How can I prevent nail infection

Proper hand & foot care is crucial in the prevention of paronychia. Regular handwashing is as important as properly drying the hands afterward. Cleaning the nails with a soft nail brush and trimming them regularly is also beneficial. People who work with their hands submerged in water should wear rubber gloves to protect their hands. Manuel workers who use their hands should also wear protective gloves to reduce the risk of trauma to the skin2,6

Avoiding biting fingers, wearing properly fitting shoes that do not pinch the toes, not wearing artificial fingernails for a long time, avoiding cutting the cuticles during manicures, and cutting the nails straight in order to avoid ingrown toenails are all important preventative measures against nail infections.2,6

How common is nail infection and who is at risk?

Although everyone can come across nail infections throughout their life, there are some people who are at increased risk. Women for example are three times more likely than men to develop paronychia. Middle-aged women have the highest risk among them to develop nail infections.4

Manuel workers, like carpenters or builders who have an increased risk of having foreign bodies pricking the skin barrier, or people with occupations that have their hands submerged in water for prolonged periods, like dishwashers or nail salon workers, are also at a higher risk for developing nail infections.2,4


Paronychia is the infection of the skin around the nail bed which is most commonly caused when improper care of the hands and feet meets some sort of microorganism, usually the ones that are part of our skin. The affected area will present swollen, red, and painful. Treatment may include drainage of the abscess in the area as well as antibiotics in either pill or cream form. Preventing nail infections is easy as proper nail care followed by hand washing, drying, and using gloves when appropriate has been proven very effective.


  1. InformedHealth.org, Institute for Quality and Efficiency in Health Care (IQWiG); 2006-.Cologne, Germany. https://www.ncbi.nlm.nih.gov/books/NBK513133
  2. NHS, Patient Info, https://patient.info/skin-conditions/paronychia-leaflet
  3. https://www.nhs.uk/conditions/nail-problems/
  4. Dulski A, Edwards CW. Paronychia. In: StatPearls. Treasure Island (FL): StatPearls Publishing; August 8, 2022. https://www.ncbi.nlm.nih.gov/books/NBK544307/
  5. O'Gara JP. Into the storm: Chasing the opportunistic pathogen Staphylococcus aureus from skin colonisation to life-threatening infections. Environ Microbiol. 2017;19(10):3823-3833. doi:10.1111/1462-2920.13833 https://ami-journals.onlinelibrary.wiley.com/doi/10.1111/1462-2920.13833
  6. Dimitris Rigopoulos, MD et al., Acute and Chronic Paronychia,  Am Fam Physician. 2008;77(3):339-346, https://www.aafp.org/pubs/afp/issues/2008/0201/p339.html
  7. https://www.nhs.uk/conditions/psoriasis/
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Kutal Mete Tekin

MRes, Bioengineering, Imperial College London

Kutal trained as a medical doctor in Istanbul before moving to London for this research masters at Imperial College London. He works as a part time medical interpreter with the NHS. His written work can also be seen in the motor sports sector as he has been a freelance sports writer and and editor since 2016.

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