Skin Infection Around Fingernails and Toenails

Paronychia is an infection of the layer of skin surrounding the nail (known as the perionychium). It can develop when bacteria enters broken skin near the cuticle at the base of the nail or when an irritation damages the skin around the fingernails or toenails and allows fungus to grow. Treatments depend on the type of infection.

Paronychia is one of the most common hand infections and is seen frequently in children as a result of nail biting and finger sucking.

This article explores the appearance of paronychia, its causes and treatments, and what you can do to prevent an infection.

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Causes

Paronychia can have different causes that may vary based on the amount of time the infection has been present. It is a condition classified as either:

• Acute: rapidly progressing with a short duration
• Chronic (ongoing and persistent)

Both acute and chronic paronychia start with the penetration of the outer layer of skin called the epidermis.

Acute paronychia is usually the result of a direct trauma to the skin, such as a cut, hangnail, or ingrown nail. Bacteria are the most common cause of the infection, predominantly Staphylococcus aureus, but also certain strains of the Streptococcus and Pseudomonas bacteria.

Meanwhile, chronic paronychia is most frequently caused by repeated exposure to water-containing detergents, alkali, or other irritants. It can lead to swelling and gradual deterioration of the epidermal layer. Chronic infections are often caused by the fungus Candida albicans (yeast) and other fungal agents.

Appearance

Acute paronychia starts as a red, warm, painful swelling of the skin around the nail. Over time, the accumulation of pus may separate the skin from the nail. In more severe cases, the lymph nodes in your elbow and armpit may swell and your nail may become discolored.

In chronic paronychia, redness and tenderness are usually less noticeable. The skin around the nail often looks baggy, and the cuticle may separate from the nail bed. The nail often becomes thickened and discolored with pronounced horizontal grooves on the surface. Green discoloration can occur in cases of Pseudomonas infection.

Diagnosis

Acute paronychia is typically diagnosed based on a review of the clinical symptoms. If pus is oozing, your healthcare provider may make an incision to drain it.

In severe cases, they may culture bacteria from the drained pus to make a definitive diagnosis. This usually isn't necessary because the bacteria is usually Staphylococcus or Streptococcus type, both of which are treated similarly.

Chronic paronychia tends to be more difficult to diagnose. A potassium hydroxide (KOH) test, using a smear is extracted from the nail fold, sometimes confirms a fungal infection. If pus is involved, a culture can confirm the presence of fungus or other, less common infectious agents.

Treatment

For an acute infection, soaking the nail in warm water three to four times a day can promote drainage and relieve some of the pain. Some healthcare providers suggest an acetic acid soak, using one part warm water and one part vinegar.

If you have pus or an abscess, the infection may need to be drained. In some cases, a portion of the nail may need to be removed.

Bacteria-associated paronychia is most commonly treated with antibiotics such as cephalexin or dicloxacillin. Topical antibiotics or anti-bacterial ointments are not considered an effective treatment.

Chronic paronychia is typically treated with a topical antifungal medication such as ketoconazole cream. In addition, a mild topical steroid may be used to help reduce inflammation. (Steroids should never be used on their own as they don't treat the underlying infection.)

Prevention

You have several options for reducing the risk or severity of a paronychial infection.

• Do not bite nails or trim them too closely.
• Never bite or cut cuticles.
• Ensure that your manicurist always uses sterile instruments.
• Try not to suck fingers.
• Wear waterproof gloves when immersing your hands in detergents, cleaning fluids, or strong chemicals.
• Avoid soaking your hands in water for prolonged periods of time (or, again, use waterproof gloves).
• For cuts and scrapes, wash your hands with antibacterial cleanser and bandage, if necessary.
• Dry your feet thoroughly if they are immersed for long periods of time in unclean water or water containing detergent or chemicals.
• Change your socks regularly and use an over-the-counter foot powder if your feet are prone to sweatiness or excessive moisture.