Human bites

Human bites are injuries and secondary infections caused by bites from humans.


Causes

Human bites are mainly injuries caused by the fist hitting the teeth and occlusive bites. The former is the most common and has great clinical significances. A clenched fist striking another person's teeth with enough force can cause a small wound, usually 3 - 8 mm in length. Injuries typically occur on the dorsal surfaces of the third and fourth metacarpals (MCP) or the proximal interphalangeal joints of the dominant hand. Because the skin in these areas is thin, potential injuries include penetration into the joints, metacarpal fractures, and extensor tendon tears. Injuries to the finger nerves or arteries are less common. Infections from injuries caused by punching the teeth with a fist are mainly in males, presumably due to their more aggressive behaviors. Occlusive bites are in males and females equally.


Signs and Symptoms

There are pain and tooth marks on the skin. Small, straight incisions across the knuckles are present if injuries are caused by bites in fights. Finger tendon tears often cause motor impairment. Pain, redness, and swelling occur after infections.

Video 1 human bites


Diagnosis

On the basis of chief complaints and clinical presentations, the condition can be diagnosed.


Treatment

Human bite wounds should be rinsed with sterile saline and soapy water.

Amputated parts can sometimes be reconnected. The amputated parts should be wrapped in wet paper towels or washcloths and sealed in a plastic bag. This sealed plastic bag should be placed in another ice bag. The amputated parts should never be placed directly on ice or submerged in water.

In general, hand wounds, puncture wounds, infected wounds, and wounds more than 12 hours should not be sutured. Other lacerations should be sutured.

All patients with damaged skin from human bites should receive oral antibiotics to prevent infection. Infected bites are treated with antibiotics. Imaging tests, such as X-rays and ultrasound, are also sometimes needed to find hidden foreign bodies. Surgery is required to remove the foreign bodies and clean the wounds.

If infections occur in bites resulting from fights, hospitalization and intravenous antibiotics may be required.

Post-exposure prophylaxes, such as hepatitis B immunoglobulin and anti-HIV medicines, should be considered if the biters are suspected.