Infection of the skin around or under the nails

Minor infections of the skin around the nail (paronychia) are common. They may be caused by repeatedly putting your hands in water or by an injury such as biting off a hangnail or pushing back a cuticle. Minimal redness, pain, or pus that only appears once or twice may clear up with 2 or 3 days of home treatment.

Signs of infection of the skin around or under the nails include:

• Pain with swelling, redness, tenderness, or heat.
• Red streaks extending from the area.
• Discharge of pus.
• A green, white, or yellow color under the nail.
• Fever.
• Swollen lymph nodes in the elbow, armpit, or groin.

You may bump or catch an artificial nail, jar it loose from your natural nail, and create a gap between the artificial nail and the natural nail. When this happens, dirt and moisture can get in the gap. A bacterial skin infection or fungal nail infection can develop if the artificial nail is reglued before you clean the gap.

Sometimes a minor infection of the skin around the nail can lead to infection under the nail (subungual abscess), a more serious infection of the skin (cellulitis), bone (osteomyelitis), or a joint (septic arthritis). Infections may also affect the entire body (sepsis).

Infection of the skin of the fingertip (felon) can also be caused by a viral infection (herpes simplex) or a bacterial infection (staphylococcal whitlow). Felon can cause destruction of large areas of tissue on the fingertip and also cause symptoms that affect the entire body.

• Felon caused by staphylococcal whitlow is usually caused by traumatic injury to the fingertip. The end of the finger will be red, hot, sore, and swollen. An abscess may form. Treatment involves surgery to drain the abscess, plus antibiotic treatment. An X-ray of the finger is usually done to determine whether infection of the bone (osteomyelitis) is present.
• Felon caused by herpes simplex appears as blister formation (vesicles). This occurs most often in people such as dentists, doctors, or nurses who are exposed to infected oral or respiratory secretions. Symptoms include intense itching and pain, followed by the formation of deep sores. A similar problem may be caused by biting your nails while you have a cold sore. This type of viral infection may respond to acyclovir. The use of rubber gloves prevents this infection in health professionals.

Diabetes and peripheral arterial disease cause reduced blood flow and loss of feeling in the feet. Untreated nail injuries can lead to infection, foot ulcers, and other serious problems.

Prompt treatment of an infection can help prevent complications.