Human and animal bites can cause an infection of the hands. Some other infections are felon and herpetic whitlow. Paronychia is discussed elsewhere (see Nail Disorders: Paronychia).

Infections Caused By Bites

The most common cause is injury to the knuckles by the teeth from a punch to the mouth. Animal bites are also common causes. Wound contamination by a number of types of bacteria can result from human and animal bites. All bite injuries are potentially dangerous and can cause significant infection.

If the skin is broken, an x-ray is often done to detect foreign bodies, which can cause or worsen infection. The injured area should be cleaned surgically, with the wound left open to drain. Antibiotics should be given to prevent joint infection (septic arthritis), which can otherwise lead to permanent destruction of the knuckle joints. Which antibiotic is effective depends on which bacteria are common in the person's community.

Felon

A felon is infection of the soft tissue (pulp) at the fingertip.

An infection of the fingertip can lead to an abscess, which creates pressure on and causes death of nearby tissues. The fingertip becomes very swollen and firm with intense throbbing pain. The doctor makes the diagnosis by examining the affected finger. If a felon is not treated promptly, the underlying bone, joint, or tendons may become infected. Treatment often requires prompt surgical drainage of the abscess, as well as antibiotics.

Herpetic Whitlow

Herpetic whitlow is a viral infection of the fingertip.

Herpes simplex virus (similar to the one causing fever blisters) may cause an intense, painful skin infection. The fingertip is sore and swollen but is not as firm as in a felon. The appearance of tiny fluid-filled blisters (vesicles) on the fingers is diagnostic. A herpetic whitlow is often mistaken for a felon. The disorder eventually goes away without treatment. Surgery is not needed.

Did You Know... The most important measure for preventing infection of bite wounds is thorough cleaning and draining.

Hand Abscess

A hand abscess is an accumulation of pus affecting the hand, usually caused by a bacterial infection.

Abscesses in the hands are fairly common and usually result from injury. A superficial abscess may develop just under the skin anywhere in the hand, and nearly always results from a minor injury, such as a splinter or needle prick. Severe pain, warmth, and redness develop over the abscess, often with swelling of nearby lymph nodes in the arm. An abscess may occur in any part of the palm and spread between the metacarpal bones (the hand bones between the wrist and fingers). Such an infection may occur after the skin is ripped or the hand is punctured by something sharp. Palm abscesses may develop from an infected callus. Palm abscesses begin as intense throbbing pain with swelling and severe tenderness to touch. The swelling and pain may be greater at the top of the hand than on the palm.

Treatment involves surgically draining the pus. Antibiotics also are given.

Infection of the Tendon Sheath

Abscesses may occur around the tendons that run along the inside of the fingers. This type of abscess is caused by an injury that penetrates one of the creases on the palm side of a finger. Pus from an untreated felon may also spread from the tip of the finger into the end of the tendon sheath. Infection and pus form around the tendon and rapidly destroy tissue. The gliding mechanism of the tendon becomes damaged, so the finger can barely move. Symptoms include swelling and pain of the finger, tenderness over the tendon sheath, and extreme pain when trying to move the finger. Swollen lymph nodes near the abscess are common. Fever is also common.

Surgical drainage of the abscess is required. Antibiotic therapy is also required.

Last full review/revision March 2008 by David R. Steinberg, MD