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Bacterial paronychia - Nail and Distal Digit
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Bacterial paronychia - Nail and Distal Digit

See also in: Overview
Contributors: Shari Lipner MD, PhD, Susan Burgin MD, Bertrand Richert MD, Robert Baran MD
Other Resources UpToDate PubMed


Acute paronychia is defined as inflammation of the proximal or lateral nail folds for fewer than 6 weeks. Pain, swelling, and redness are the cardinal symptoms, sometimes accompanied by abscess formation.

Acute paronychia frequently arises from trauma to one of the nail folds, resulting in compromise of the physiologic barrier to entry of microorganisms. Inflammation may proceed to bacterial infection, resulting in pus. In some cases, the abscess tracks under the nail plate, and if not treated quickly, it can result in permanent damage to the nail matrix.

Examples of inciting trauma include foreign bodies, such as splinters; manipulations, such as manicures or pedicures; ingrown nails; fingernail biting; finger sucking in children; or "hangnail" removal. Occasionally, acute paronychia arises as a painful exacerbation of chronic paronychia, which is now understood to be a localized form of chronic irritant or allergic dermatitis.

Certain drugs – including retinoids (isotretinoin, acitretin), methotrexate, antiretroviral protease inhibitors (indinavir, lamivudine), and epidermal growth factor receptor (EGF) inhibitors (cetuximab, gefitinib, lapatinib) – can cause drug-induced paronychia, in some cases with associated periungual lobular capillary hemangioma (pyogenic granuloma).

Specific bacteria predominate in trauma-related acute paronychia. They include Staphylococcus aureus, Streptococcus pyogenes, and anaerobic bacteria derived from the oral flora. Mixed bacterial flora are common. Other bacteria that have been reported as causes include:
  • Pseudomonas
  • Enterococcus faecalis
  • Enterobacter cloacae
  • Proteus
  • Hendersonula
  • Scytalidium
  • Fusarium
  • Prevotella
  • Bartonella
Patients with diabetes mellitus may be at increased risk of acute paronychia.


L03.019 – Cellulitis of unspecified finger

247517004 – Bacterial paronychia

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Last Reviewed:07/27/2017
Last Updated:07/21/2021
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Patient Information for Bacterial paronychia - Nail and Distal Digit
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Paronychia, commonly known as bacterial nail infection, is inflammation of the region of the finger or toe where the nail starts to grow, which is called the proximal nail fold (PNF). Paronychia is usually caused by a bacterial infection but can be caused by a yeast or virus, typically the herpes simplex virus (HSV). This inflammation may occur all of a sudden or may be a long-term problem or one that keeps coming back (chronic).

Bacterial paronychia develops fairly quickly over a period of days along a break in the skin and is usually seen at the side of the nail.

Who’s At Risk

Bacterial paronychia may occur at any age but is particularly common in children.

Signs & Symptoms

Bacterial nail infection most often affects the proximal nail fold of the fingers and less commonly affects the toes.

The proximal nail fold is red, swollen, painful, and may contain pus. Usually one nail is affected.

Self-Care Guidelines

Try soaking the nails in warm water.

When to Seek Medical Care

See your doctor for an evaluation if you notice signs of worsening infection.


For bacterial paronychia, your doctor may:
  • Puncture and drain the affected area and test for bacteria.
  • Prescribe antibiotics for a bacterial infection.
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Bacterial paronychia - Nail and Distal Digit
See also in: Overview
A medical illustration showing key findings of Bacterial paronychia : Nail fold erythema and edema, Nail fold pustule, Nail pain
Clinical image of Bacterial paronychia - imageId=2698187. Click to open in gallery.
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