Human Bites

Reviewed on 11/10/2021

Facts You Should Know About Human Bites

Treatment of a human bite depends on the seriousness of the bite.
Treatment of a human bite depends on the seriousness of the bite.
  • Human bites can be either quite serious or relatively harmless.
  • It is important to know which ones need medical attention.
  • Human bites consist of a range of injuries, including intentionally inflicted bites, but also any injury caused by coming in contact with the teeth of another person.
  • For example, if two children collide and the tooth of one causes a cut on the other, this is classified as a human bite.

What Causes a Human Bite?

Human bites can be either accidental or intentional.

  • Intentional bite injury: This generally happens during fights and can result in a wide range of injuries from minor bruising to partial loss of body parts (for example, ears or nose). Unfortunately, this can also be an injury seen in child abuse, sexual abuse, and self-mutilation.
  • Closed fist injuries: This bite occurs when someone punches another person in the mouth or, occasionally, accidentally strikes another in the mouth during sports or horseplay. These bites can cause damaging hand injuries and can be very serious if not properly treated. It is important to share this information with your healthcare professional as a cut secondary to contact with a person's mouth is treated significantly different from a cut due to a sharp surface or knife.
  • Accidental bites: Typical head or other body part bites occur when clashing with another person's tooth. These can be minor or, in the case of a head wound in young children, very serious.
  • "I didn't know it was a bite!" category: Yes, we frequently run the risk of problems from doing things to ourselves that technically qualify as bites. For example, it is not a good idea to bite your nails because this can lead to an infection known as paronychia or a hangnail. Similarly, it is almost a reflex to suck on wounds or to kiss a child's boo-boo, but if you introduce mouth bacteria, it could lead to problems such as an infection.
  • Love bites (for example, hickeys): These qualify as a human bite. However, if bruising is the only sign with no skin break, these are largely harmless. Other "love bites" cross the line into intentionally inflicted wounds and may be more serious. Any bite marks in the genital area in children need to be evaluated as a possible sign of abuse.

What Are Signs and Symptoms of Human Bites?

A human bite is generally obvious, but on occasion the victim is unaware (for example, the bite occurred while the victim was drunk) or reluctant to tell others (for example, a hand injury due to a fight). Use caution in ignoring cuts over the knuckles if there is the chance the cut happened in a fight, especially if the cuts came from hitting another person in the mouth. Otherwise, the two most important things to know about a bite are whether there is a skin break or signs of infection.

Signs of a skin break

  • A skin break increases the risk of infection, and it also makes it necessary to give a tetanus booster if the affected person's tetanus status is not up to date. A skin break is often obvious but can be difficult to tell in some cases. Any skin area that looks like the top layer of skin has come off should be considered a skin break. When in doubt, seek a health care professional's opinion. A raw appearance to the area or the oozing of clear fluid is a sign of a skin break.

Signs of infection (note that infection can occur even in properly treated bites)

  • Increasing pain and tenderness: Although all bites hurt initially, the pain usually gets steadily better. If a bite begins to hurt more after time passes, this can be the first sign of infection. Increased pain from an infection is usually matched by increased tenderness when the area of the bite is touched. Typically, this begins 1-2 days after the bite but can occur even later with deeper infections.
  • Increased or new redness: Some color changes can be expected at the beginning, particularly bruising and some redness, but this usually does not get much worse after the first few hours. An increase in redness is a warning sign of infection.
  • Increased swelling: Some swelling is expected initially, but this usually peaks on the first day. If the bite swells up more after the first day, it may be a sign of infection.
  • Fever: A new fever in someone with a bite should be cause for concern. However, waiting for a fever to be sure there is an infection is also wrong. Most people with human bite infections do not get a fever until the infection has spread significantly. If the area around the bite itself feels very warm, even if there is no actual rise in the whole body temperature, this could also be a sign if an infected wound bite.
  • Pus drainage: Pus is yellow and will generally be a late sign of infection. This drainage needs to be distinguished from clear oozing that can occur during the first few hours if the skin is scraped by teeth. This clear oozing is not a sign of infection. If in doubt, the affected person should consult a healthcare practitioner.
  • Red streaks: When you can see thin red streaks running toward the center of the body from a wound, infection is usually present. This condition is sometimes called blood poisoning (the medical term for this condition is lymphangitis), even though this has nothing to do with the bloodstream. What is occurring is an inflammation of the lymph vessels, part of the body's defense system against infection that includes the lymph glands or nodes. Signs and symptoms of lymphangitis should trigger an immediate visit to your health care professional or emergency department.
  • Swollen glands: These may occur in areas near the bite as the lymph glands react to protect the body. For example, if a hand is infected, sore, swollen glands on the inside of the elbow or armpit of the same arm as the bite may develop.

When Should I Call the Doctor About a Human Bite?

Even with what appears to be a minor bite, contact a doctor to be sure a tetanus shot is not needed. Once the skin is broken, the doctor should be consulted because the risk of infection is higher. Any sign of infection, even if the affected person has already been seen by the doctor, is a reason to call.

If there is any suspicion that part of a tooth is in the bite wound (foreign body), people should seek medical care as this will increase the risk of the infection.

Using the hospital's emergency department for a human bite is often the proper treatment to seek. Emergency doctors generally have a lot of experience with bites and other wounds. People who do not have a doctor or who cannot get in touch with their doctor may have to use the emergency department even for minor bites in order to get a tetanus shot and a doctor's opinion of the need for other treatment, such as antibiotics.

  • Closed fist injuries: Bites over the knuckles are very serious. These are at high risk for infection. Once infected, these bites can lead to major damage to the important parts of the hand. Additionally, the force of punching someone in the mouth can lead to broken bones or cuts in the tendons, and those need expert care. An infected bite in this area will usually require an overnight stay in the hospital.
  • Finger chomping injuries: Just like the closed fist injury, this human bite can lead to serious problems. The bones and tendons can be injured and are at risk for infection.
  • Bites with tissue loss: If a significant part of skin and muscle tissue is lost, the patient needs to seek medical care as soon as possible. An expert (for example, a hand surgeon) can often repair loss of a tissue part as the result of a human bite.
  • Deep bites: Any bite that bleeds a lot or appears to be more than a scrape needs thorough cleaning and examination.
  • Infected bites: Bites that are infected often require the patient to stay in the hospital and receive antibiotics through an IV. The doctor will determine if treatment with oral antibiotics is possible or if IV medication and a hospital stay is warranted.
  • Bites of the head in children: Because of the thin nature of the scalp and the risk of a serious infection, any cut in a child's scalp (including the forehead) that was caused by a tooth should be evaluated by a healthcare professional.
  • Bites in other special areas: Bites of the ear and nose are a problem because of the cartilage in this area. Due to decreased blood flow, an infection of the cartilage can be very difficult to treat and can cause permanent damage.

How Do Doctors Diagnose Human Bites?

The doctor will begin an evaluation generally with a series of questions that will include how the bite happened, when it occurred, what first aid procedures were performed, and any symptoms the patient is having. The doctor will want to know if tetanus shots are up-to-date, so bring any records of immunizations the person may have. A list of the person's medical problems and medications will also help expedite care.

  • Physical examination: This involves looking in and around the wound to see what damage has occurred. With minor bites this is often just a quick look to see if the skin is broken or not. With deeper bites the doctor may have to anesthetize the area to allow a thorough examination of the affected area. Tests of nerve and tendon function (how well a patient can feel things and move body parts) are usually part of the examination.
  • X-rays: Most bites will not require this unless a broken bone is possible. X-rays are often obtained on closed fist injuries and other bites to the hand to rule out gas formation or foreign bodies. X-rays may also be obtained if the doctor believes a piece of a broken tooth may be in the wound.
  • Blood tests: Blood tests are usually not performed in human bites. Even infected bites do not usually require a blood test to make the diagnosis. If a patient has to stay in the hospital, chances are likely some blood tests will be ordered. If there is a concern about the transmission of HIV or other illness due to a bite, the doctor might order blood tests. These tests can include an HIV test (to determine baseline status) as well as tests to determine if the patient will be able to tolerate other possible medications.

What Is the Treatment for Human Bites?

Treatment of a human bite can be anything from ice packs for swelling (no skin breakage) to surgery, depending on the seriousness of the bite. For serious bites, early treatment is important to give the best chance at preventing infection.

What Are the Home Remedies for Human Bites?

First aid for a bite usually just involves cleaning the area and applying ice for pain relief. Bites generally do not bleed a large amount, but, if they do, put direct pressure on the area for 10 minutes, which should stop the bleeding. Elevation of the injured area above the level of the heart may also help stop bleeding and prevent swelling of the wound.

  • Save all tissue parts: Make sure any tissue that is bitten off is brought to the hospital's emergency department. If the doctor cannot reattach it, the hospital will dispose of it. If the patient needs to travel a distance to get medical care, place the part in a plastic bag in ice water (not directly on ice).
  • Keep cleaning simple: Run large amounts of cool clean water over the wound. A mild soap is fine, but do not pour alcohol or peroxide on an open wound because this can injure the tissue. A good rule of cleaning is that anything put on a wound that causes burning or increased pain probably does more harm than good.
  • Do not use butter or home remedies. It is best to leave the wound uncovered until checked by a doctor.
  • Apply ice for pain relief: Wrap some ice in a towel and apply it to the area. This will ease the pain and help keep the swelling down. Do not apply ice directly on the skin because it may freeze the skin. Some doctors recommend about 15-minute intervals of ice wrap followed by about 15 minutes of ice wrap off. This sequence is repeated until the patient is evaluated by medical personnel.

What Is the Medical Treatment for Human Bites?

Minor bites: A bite that just causes bruising or only scrapes the top layer of skin will not require much more than cleaning with soap and water, ice, and mild pain medication such as acetaminophen (Tylenol). A tetanus shot may be needed if the skin is broken and the patient has not had a booster tetanus in the last five years. Antibiotics are usually not necessary for this type of bite.

Deeper bites or bites causing cuts: Besides giving a tetanus shot when appropriate, the doctor will generally numb these bites with medicine (such as lidocaine) and then thoroughly clean and examine the wound. Cleaning of the wound, unless it is a puncture wound or very small, will usually involve squirting a large amount of clean water into the wound. With an open wound, sometimes large amounts of water directly from the tap are used to flush it out. Occasionally, a small amount of an antiseptic solution is added to the water before rinsing the wound, or skin around the wound. In the cleaning process, the doctor may cut out small pieces of tissue that appear to be dead. This helps decrease the risk of infection.

Stitches (sutures): The decision to use or not use stitches in a human bite depends on many factors. Doctors tend to use stitches less often in cuts caused by human bites because of the high risk of infection, especially from mouth to bacteria that may thrive in injured or dying or dead tissue (devitalized tissues). On the other hand, certain bites, especially those of the face, may turn out better if stitches are used, and the risk of infection in this area is not that high. Some stitches may only "loosely" close the wound to help the bite wound drain, but not provide an environment for growth areas for mouth bacteria.

  • A very deep cut in the tongue, for example, will usually be stitched even though it is a human bite because doctors know that it will usually not become infected even if stitched.
  • Most small cuts heal on their own even if stitches are not used. Sometimes the doctor will have the patient return in 4-5 days to see if stitches can then be used to close a large cut caused by a bite. This is called delayed closure.

Other treatment: The doctor may apply a splint to the bite area to keep it from moving. A sling may be used to help keep an injured hand elevated. Pain medication may be prescribed.

The doctor may suggest prophylaxis against HIV transmission in the form of medications.

What Are the Medications for Human Bites?

Antibiotics: The decision to use antibiotics also involves a number of factors about the bite and the person who was bitten. In many cases there are no definite answers from medical research, and doctors use their judgment to determine if antibiotics are used. The current recommendations from the Infectious Disease Society of America (IDSA) call for the use of amoxicillin/clavulanate (Augmentin) or ampicillin/sulbactam (Unasyn) for human bites that may become or are infected because such antibiotics are usually effective against Eikenella corrodens, a bacteria species often involved in human bite infections.

Following are some general points on antibiotic use in human bites.

  • Minor bites with no or superficial skin break: Antibiotics are not needed.
  • Infected bites: Antibiotics are given either orally or by IV, depending on how severe the infection is.
  • Closed fist injuries: Antibiotics are usually needed in this human bite. When initially treated, oral antibiotics are usually prescribed. Sometimes the doctor in the emergency department may give the first dose into the muscle or veins. If already infected, these bites are usually treated in the hospital with IV antibiotics.
  • Medications to prevent transmission of HIV: The patient and their doctor should discuss the risk of transmission of HIV by a bite and the possibility of starting medications that decrease the risk of HIV transmission. The faster these medications are started, the more effective they seem to be.

What Is the Follow-up for Human Bites?

  • The important thing to remember is that a bite may become infected even with proper treatment. In general, the doctor will give the patient a list of warning signs of infection.
  • If a patient has signs of infection, do not wait for a fever to develop before contacting a health care professional.
  • Be sure to take any prescribed medication as directed for the full course.
  • Use elevation and any other treatment recommended by the doctor to lessen the risk of infection.

How Do You Prevent Human Bites?

Lessen the risk of human bites as indicated below.

  • Use mouth guards in sports.
  • Avoid fist fighting.
  • Keep a close eye on toddlers who may bite a younger sibling or playmate (males bite more often than females).
  • Institutionalized people who bite themselves or others may require protective face shields.
  • Avoid biting fingernails and sucking on or "kissing" open wounds in other people.

What Is the Prognosis for Human Bites?

The best way to ensure a good outcome of a human bite is to receive needed treatment before infection can set in. Infected bites, especially the closed fist injury and other bites of the hand, can cause permanent damage and interfere with normal function. Infections of the ear and nose cartilage can be very hard to treat. Fortunately, there are many powerful antibiotics available, so even infected human bites usually do quite well once proper treatment is started.

All human bites that break the skin need to be evaluated for the risk of transmission of HIV and the need for a tetanus booster.

Reviewed on 11/10/2021
Medically reviewed by John A. Daller, MD; American Board of Surgery with subspecialty certification in surgical critical care

"Human Bites in Emergency Medicine Treatment & Management."