Traumatic Human Bite Wound on the Lower Lip: A Case Report

Human bites account for approximately 1–3% of bite-related emergency presentations, with the face being the most frequently affected region due to its prominence in interpersonal violence^1,2. Globally, maxillofacial bite injuries are often linked to assault, with women disproportionately affected³. Regional studies across Africa consistently report the lower lip as the most vulnerable site, particularly among female victims^4,5. In Zambia, the prevalence of intimate partner violence is estimated at 21%, underscoring the sociocultural determinants driving such presentations⁶. This highlights how human bite injuries not only reflect surgical concerns but also broader public health and social justice issues.

The lesion in our case corresponds to Lackmann’s Type IIIA injury, characterized by deep soft tissue avulsion with a tissue defect. Such higher-grade injuries require meticulous reconstruction to restore oral competence, articulation, and acceptable aesthetics⁷. Our patient underwent layered primary closure following irrigation and conservative debridement, which remains the cornerstone of effective management. Copious irrigation reduces bacterial load and removes particulate matter, with normal saline being the irrigant of choice as it preserves tissue viability and avoids interference with wound healing, unlike most antiseptics^8,9. Techniques may range from manual syringe irrigation (20–35 mL syringe, 18–20G needle) to pulsatile jet lavage at pressures of 50–70 psi⁹.

Although delayed wound closure was historically preferred because of the fear of infection, current evidence supports primary closure of well-prepared facial bite wounds due to the excellent vascularity of the region and favorable cosmetic outcomes^2,10. Our case adds to this evidence, as the patient achieved good healing, intact lip function, and minimal scarring within three months of follow-up.

Human bite wounds are polymicrobial, typically involving Eikenella corrodens, Streptococcus spp., Staphylococcus aureus, and anaerobes¹¹. The Infectious Diseases Society of America (IDSA) recommends empiric prophylaxis with amoxicillin–clavulanate or intravenous ampicillin–sulbactam; alternatives include quinolones plus metronidazole for penicillin-allergic patients¹². Our use of amoxicillin plus metronidazole offered anaerobic coverage but lacked β-lactamase inhibition against Eikenella, reflecting a formulary limitation common in district hospitals across Africa. This underscores systemic gaps in antibiotic availability¹².

Beyond infection control, prophylaxis against tetanus was correctly provided¹². Rabies prophylaxis is not indicated for human bites in Zambia, given the negligible risk. However, HIV transmission, though rare, is biologically plausible when blood is exchanged through deep bites. Both WHO (2024) and CDC (2025) recommend risk-based HIV testing with immediate initiation of post-exposure prophylaxis (PEP) within 72 hours^13,14. Our administration of PEP aligned with these guidelines and highlights best practice in resource-constrained environments where HIV prevalence remains significant.

Surgical reconstruction of human bite injuries in the lip should adhere to basic principles: preservation of viable tissue, restoration of oral competence, and re-establishment of normal anatomical relationships with acceptable aesthetics¹⁵. Over-aggressive debridement should be avoided in the face due to its rich vascularity, which allows even marginal tissues to survive¹⁶. Landmark structures such as the vermilion border, nasolabial fold, and philtrum must be preserved to maintain facial symmetry. In our case, layered closure with minimal subcutaneous sutures provided excellent functional recovery and cosmetic acceptability, consistent with the literature^2,7,16.

This case highlights not only the surgical dimension of human bite injuries but also the public health context. In Zambia, where intimate partner violence remains a major driver of such trauma, clinical management must be integrated with violence-prevention strategies, psychosocial support, and medico-legal documentation⁶. Furthermore, common constraints in African district hospitals—including lack of wound cultures and limited antibiotic formularies—were evident in this case but did not prevent a favourable outcome.

Practice Points

Copious irrigation and conservative debridement are essential to infection prevention^8,9.

Primary closure of facial bites is generally safe and cosmetically superior^2,10.

Empiric antibiotics should ideally cover Eikenella and anaerobes; amoxicillin–clavulanate is first-line^11,12.

Tetanus prophylaxis and timely HIV testing with PEP initiation remain critical^13,14.

Management of human bite injuries must integrate violence-prevention measures and medico-legal reporting⁶.

This case reinforces that even in resource-limited country’s hospitals, favourable outcomes in severe human bite injuries can be achieved through thorough irrigation, conservative debridement, primary layered closure, and appropriate prophylaxis. Beyond surgical repair, such injuries must be recognized as both a clinical and social problem, demanding multisectoral collaboration between healthcare, law enforcement, and community support systems.

Consent: Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.

Competing interests: The authors declare that they have no competing interests.

Authors’ contributions: GM was the consultant responsible for diagnosing and treating the patient in this case report. GM provided the information to JS who co-wrote the paper. All authors have read and approved the final version of this manuscript.