The clinical presentation of human bites depends on several factors, and two main types of bites are described in the literature [1] [2]:

• Occlusion bites - The vast majority of human bites are occlusion bites, developing when skin and underlying tissue is damaged directly by the teeth and the force by which they press against the skin [1] [2] [3].
• Closed fist injuries - When a closed fist impacts the teeth (usually during a fight) with such force that it causes penetration of the skin and subsequent injury, the term closed fist (or clenched fist) bite is used [1] [2]. The metacarpophalangeal (MCP) joints and tendons are most frequently affected by closed fist injuries, potentially resulting in significant tendon injury or even septic arthritis [1] [2].

Virtually any site of the body is a target of a human bite, but the principal locations are the hands and fingers, the extremities, and the head and neck area [1] [2] [3]. Human bites are much more frequent among males, with a median age of presentation established at 28 years of age [1]. Although human bites do not cause profound destruction of the affected tissues directly, the reason why early recognition is necessary is the risk for wound infection from the bacteria that were introduced from the oral cavity, especially because they are able to descend into deeper tissues once the integrity of the skin is disrupted [1] [2] [3] [4] [5]. Studies have shown that 10-25% of human bite victims will develop a wound infection, and principal causative agents are Streptococcus angiosus, Staphylococcus aureus, Fusobacterium, Prevotella melaninogenica, and Eikenella corrodens, whereas Peptostreptococcus, but also Candida sp. are described as well [1] [4] [5]. More importantly, the infection can often be polymicrobial, which often complicates the therapeutic approach [1]. The clinical presentation of human bites is not always evident, particularly in the absence of a clear bite mark on the skin. If localized swelling, purulent and foul-smelling discharge, and erythema are present, a strong suspicion of a wound infection must be made [4] [6]. These signs appear within the first few days after the bite and may be accompanied by a fever and proximal lymphadenopathy [4]. Patients suffering from an underlying immunosuppressive disease, liver failure, or systemic lupus erythematosus (SLE) have shown to be at an increased risk for infection [4].

• Chronic Infection

  It is frequently associated with chronic infection and abscess formation. This pathogen is isolated in 30% of human bite wounds. Other commonly isolated anaerobes include Bacteroides, Fusobacteria, Prevotella, and Peptostreptococcus species. [emedicine.medscape.com]

  Willingness of directors of child care centers to care for children with chronic infections. Pediatr Infect Dis J 2001;20:77-9. Hayashi J, Kashiwagi S, Nomura H, Kajiyama W, Ikematsu H. Hepatitis B virus transmission in nursery schools. [cps.ca]

• Foul Smelling Discharge

  If localized swelling, purulent and foul-smelling discharge, and erythema are present, a strong suspicion of a wound infection must be made. [symptoma.com]

• Vascular Disease

  They are particularly notorious due to the polymicrobial nature of human saliva inoculated in the wound and the risk they pose for transmission of infectious diseases. [ncbi.nlm.nih.gov]

• Erythema

  and drainage over wound Physical exam fight bite small wound over dorsal aspect of MCP joint wound often transverse, irregular typically 3rd and/or 4th MCPs, but can involve any digit erythema, warmth, and/or edema overlying wound and joint ± purulent [orthobullets.com]

  If localized swelling, purulent and foul-smelling discharge, and erythema are present, a strong suspicion of a wound infection must be made. [symptoma.com]

  Typical signs and symptoms include: Pain, swelling, erythema Limited range of motion Lymphadenopathy Fever Patients occasionally present prior to onset of infection and may have a benign-appearing laceration. 3 Imaging and Diagnostic Studies Radiographs [orthopaedicsone.com]

  Typically, patients arrive to consult after 5 to 7 days with a fight bite, infected wound (open cut), swelling, erythema, pain, and limited range of motion, increase of local temperature. [ispub.com]

• Distractibility

  A third group with articular and/or bone destruction (89 patients) was treated the same way as group 2 with the addition of a distraction device to fix and "unload" the joint. [ncbi.nlm.nih.gov]

Because secondary infections of the wounds caused by human bites potentially lead to significant local tissue destruction, physicians must make a prompt diagnosis. They can only do so, however, by obtaining a detailed patient history and performing a meticulous physical examination. Patients must be asked about the setting and the time of injury, as well as the exact location, which could be identified during the inspection [6]. A detailed personal history, including identification of immunosuppressive disorders or diabetes mellitus, is also important [6]. If possible, a detailed patient history of the individual who bit the patient should be obtained as well, as numerous infections, both bacterial and viral (hepatitis B, hepatitis C, and theoretically HIV) can be transmitted through a human bite [1] [2] [4]. The physical exam needs to cover the presence of localized symptoms, the extent of soft-tissue injury and depth of the bite, but also if any foreign bodies are present in the wound [1] [6]. One of the typical findings of a human bite is the distance between the teeth marks in adults. Namely, the average distance of maxillary canine teeth in adults is about 3 cm, which may be a useful tool for making the diagnosis if data during history taking are inconclusive [1]. Imaging studies, in the form of plain radiography, computed tomography (CT), or ultrasonography, might be performed to assess the extent of the soft-tissue injury, while microbiological studies of the samples obtained from the wound are necessary to reveal the underlying pathogen responsible for the infection [1] [6].

Prompt assessment and treatment can prevent most bite wound complications. [ncbi.nlm.nih.gov]

Clean the wound Copious irrigation Debridement of devitalized tissue 2 Operative Treatment Incision and drainage will usually be necessary. [orthopaedicsone.com]

Treatment Treatment involves surgical attention as well as medications. Because bites cause puncturing and tearing of skin rather than clean-edged cuts, they must be carefully cleansed. [medical-dictionary.thefreedictionary.com]

Prognosis The prognosis depends on the location of the bite and whether it was caused by a child or an adult. Bites caused by children rarely become infected because they are usually shallow. [medical-dictionary.thefreedictionary.com]

The aim of the study was to assess the occurrence, treatment modalities and prognosis of human bite injuries in the oro-facial region at the Muhimbili National Hospital Dar es Salaam, Tanzania. [bmcoralhealth.biomedcentral.com]

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. [emedicinehealth.com]

Hepatitis B virus (HBV) can be detected in saliva of carriers and epidemiological studies suggest human bite as a possible route of transmission. [ncbi.nlm.nih.gov]

Introduction Epidemiology incidence third most common bite behind dog and cat demographics more common in males location typically dorsal aspect of 3rd or 4th MCP joint "fight bite" Pathophyiology mechanism most often result of direct clenched-fist trauma [orthobullets.com]

Introduction The epidemiological data has supported the premise that HIV transmission via saliva is low or non-existent due to inhibitory factors in saliva. [link.springer.com]

A randomized study founded that in patients who presented to consult in the 24 hours after lesion without signs of infection and no deep structure damage 50% still became infected.( 10 ) Pathophysiology These injuries occur usually over the dorsal aspect [ispub.com]

The rate of infection secondary to human bites is estimated to be about 10%.[ 4 ] PATHOPHYSIOLOGY Human bites can be classified depending on the mechanism of injury into occlusion bites and the closed fist bite (or fight bite). [ncbi.nlm.nih.gov]

Prevention Prevention of human bite infections depends upon prompt treatment of any bite caused by a human being, particularly a closed-fist injury. Resources Periodicals "Do All Human Bite Wounds Need Antibiotics?" [medical-dictionary.thefreedictionary.com]

It could be prevented by immediate tetanus prophylaxis, thorough debridement, and primary repair of the wound. [ncbi.nlm.nih.gov]

Most people with human bites that have broken the skin are given antibiotics by mouth to prevent infection. [msdmanuals.com]

1. Patil PD, Panchabhai TS, Galwankar SC. Managing human bites. J Emerg Trauma Shock. 2009;2(3):186-190.
2. Henry FP, Purcell EM, Eadie PA. The human bite injury: a clinical audit and discussion regarding the management of this alcohol fuelled phenomenon. Emergency Medicine Journal : EMJ. 2007;24(7):455-458.
3. Merchant RC, Zabbo CP, Mayer KH, Becker BM. Factors associated with delay to emergency department presentation, antibiotic usage and admission for human bite injuries. CJEM. 2007;9(6):441-448.
4. Stierman KL, Lloyd KM, De Luca-Pytell DM, Phillips LG, Calhoun KH. Treatment and outcome of human bites in the head and neck. Otolaryngol Head Neck Surg. 2003;128(6):795-801.
5. Talan DA, Abrahamian FM, Moran GJ, Citron DM, Tan JO, Goldstein EJ. Emergency Medicine Human Bite Infection Study Group. Clinical presentation and bacteriologic analysis of infected human bites in patients presenting to emergency departments. Clin Infect Dis. 2003;37(11):1481-1489.
6. Rothe K, Tsokos M, Handrick W. Animal and Human Bite Wounds. Deutsches Ärzteblatt International. 2015;112(25):433-443.