Human Bite

First aid for a human bite

1. Wash immediately: run clean water over the wound and wash with soap for at least 5 minutes, even if it looks minor.
2. Encourage gentle bleeding for a short time from small puncture wounds, then apply pressure with a clean cloth to stop it.
3. Cover with a clean, dry dressing. Do not close the wound with tape or glue.
4. Raise the injured area, especially a hand.
5. Remove rings if the hand is bitten.
6. See a doctor the same day for any bite that broke the skin.

Why human bites are risky

The human mouth contains hundreds of bacterial species. Bites inject them deep into tissue. Important bacteria include Streptococcus, Staphylococcus aureus and Eikenella corrodens, plus anaerobic bacteria that grow without oxygen.

Fight bites (clenched-fist injuries)

When a fist strikes teeth, a small cut forms over the knuckle. When the hand relaxes, the tendon slides back and seals the bacteria deep inside, near the tendon and joint. These injuries often look trivial but can lead to septic arthritis, tendon infection or osteomyelitis. People sometimes delay care out of embarrassment, which increases the risk. Any wound over a knuckle after a punch should be treated as a human bite.

Signs of infection

Infection usually appears within 24 to 72 hours:

• increasing pain, redness, warmth and swelling
• pus or a foul smell
• red streaks spreading from the wound
• swollen lymph nodes in the elbow or armpit
• fever and chills
• stiffness or pain when moving a finger, which may mean a tendon or joint infection

See wound infection and cellulitis.

Medical assessment

A clinician will:

• clean and explore the wound, checking for tendon, joint or bone damage, especially on the hand
• take X-rays for knuckle injuries to look for fractures or tooth fragments
• check tetanus vaccination status
• consider blood-borne infection risk

Treatment

Antibiotics

Preventive antibiotics are recommended for most human bites that break the skin, especially hand bites. Amoxicillin-clavulanate is the usual first choice. People allergic to penicillin receive an alternative combination. Established infections may need IV antibiotics.

Wound care

• Wounds are irrigated thoroughly.
• Many bite wounds, especially on the hands, are left open to drain and heal, rather than stitched, to reduce infection risk.
• Facial bites are often closed for appearance after careful cleaning.
• Splinting and raising a bitten hand help healing.
• Follow-up within 24 to 48 hours is often arranged.

Surgery

Fight bites involving joints or tendons, or infections that do not respond to antibiotics, may need surgical washout by a hand surgeon.

Tetanus

A tetanus booster is given if it has been more than 5 years since the last dose for this type of wound, or if vaccination status is unknown. See tetanus.

Blood-borne infections

Transmission of hepatitis B, hepatitis C or HIV by bites is rare, but possible if the biter's mouth contained blood. The clinician may offer testing and, for hepatitis B, vaccination or immunoglobulin if you are not immune. HIV post-exposure prevention is considered only in specific high-risk situations.

Bites in children

Toddlers commonly bite each other in childcare. Most bites only bruise the skin and need washing and a cold compress. If the skin is broken, the child should be seen by a doctor, especially if the bite is deep or on the hand or face.

Frequently asked questions

Does a human bite need antibiotics?

Most human bites that break the skin, especially on the hands, are treated with preventive antibiotics because of the high risk of infection. Bites that only bruise the skin usually do not need them. A doctor will decide based on the location and depth.

What is a fight bite?

A fight bite is a cut over the knuckles caused by punching someone in the mouth. The teeth carry bacteria deep into the hand, where they can infect tendons and joints. It needs prompt medical care even if the cut is small.

How soon after a human bite should I see a doctor?

Wash the wound immediately and see a doctor within a few hours, ideally within 8 hours, for any bite that breaks the skin. Infections can develop within a day, and hand bites can damage tendons and joints quickly.

Can you get HIV or hepatitis from a human bite?

It is very rare. Transmission is possible mainly when the biter's saliva contains blood. Hepatitis B is the most significant risk. Your doctor may recommend blood tests and hepatitis B vaccination or immunoglobulin.