eMedicine Specialties > Infectious Diseases > Skin and Soft-Tissue Infections
Human Bite Infections: Treatment & Medication
Updated: Aug 5, 2009
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
Treatment
Medical Care
Although rare, human bites have been shown to transmit Clostridium tetani. Assess all patients for tetanus immune status and update as appropriate. Erring on the side of caution when deciding to administer tetanus toxoid or tetanus immune globulin is best. These wounds are often several days old and are heavily contaminated or even infected upon first presentation. Bites with no significant skin penetration (abrasions or contusions) require no further care.
- Human bite wounds at risk for transmission of life-threatening disease require individualization of therapy.
- A fully informed patient may make appropriate choices regarding viral prophylaxis when risks and benefits are clearly explained and understood.
- Hepatitis B
- Offer the patient a single dose of hepatitis B immunoglobulin (HBIG) and an accelerated course of hepatitis B vaccine with doses at 0, 1, and 2 months, unless the patient is known to be immune.
- If the assailant's hepatitis B status is unknown but is considered high risk and the assailant is unavailable for testing, offer an accelerated course of the hepatitis B vaccine to the patient.
- If the assailant's status is unknown but is considered low risk and the assailant is unavailable for testing, the accelerated course of the hepatitis B vaccine may be offered to the patient with the understanding that the likelihood of disease transmission is low.
- Human immunodeficiency virus
- If the assailant is known to carry HIV or is considered high risk but unavailable for testing, the Centers for Disease Control and Prevention (CDC) recommends that patients exposed to potentially infectious fluids be offered zidovudine and, possibly, lamivudine chemoprophylaxis.
- Draw a baseline specimen from the patient to determine preexposure HIV status.
- Retest the patient at 3 and 6 months.
- Failure to convert to HIV-positive status at 6 months makes transmission highly unlikely.
Surgical Care
- Surgical intervention is frequently necessary, ranging from simple wound exploration and debridement to repair of complex structures under magnification.
- Certain patients (eg, children, persons who are emotionally unstable, persons who are mentally handicapped) may require surgical exploration under anesthesia to adequately examine the wound.
- Indications for surgical intervention
- Severe soft tissue infection
- Abscess
- Joint penetration
- Underlying fracture
- Tendon laceration
- Osteomyelitis
- Tenosynovitis
- Septic arthritis
- Neurovascular compromise or injury to a complex structure
- Foreign body
Consultations
A multidisciplinary approach can lead to maximum patient benefit in certain circumstances.
- Refer to a hand surgeon any hand injury with suspicion of tendon injury, fracture, joint space violation, retained foreign body, injury to nerve or vessel, or significant tissue loss. These have a significant risk for permanent disability and should be referred to a hand therapist.
- Refer to a plastic surgeon any head or neck wound with suspicion of violation of cartilage, retained foreign body, or injury to nerves, vessels, or other complex structure. Also refer to a plastic surgeon any wounds that have caused significant tissue loss creating difficult closure.
Activity
After initial immobilization of hand injuries in a position of function and elevation, provide instruction regarding resumption of activity.
- In general, early mobilization (ie, 48-72 h postinjury), once improvement is noted, prevents one of the most common and difficult complications of hand injuries: the stiff joint.
- Continue elevation until edema resolves.
Medication
The question of which patients require antibiotic therapy is a matter of considerable debate. Antibiotics cannot avert or cure infections in the face of poor wound care, reflecting the importance of meticulous treatment of the wound as the cornerstone of therapy. In regard to antibiotic therapy, it is best to err on the side of caution because the risks of antibiotic therapy are minimal, while the potential complications of bite wound infections are considerable.
In general, superficial noninfected wounds involving sites other than the hand that are evaluated early in the compliant patient without significant comorbidities may be treated without antibiotics if the wound is left open to heal by secondary intention.
Wounds of the hand, infected wounds, and wounds of the head and neck closed primarily mandate antibiotic therapy.
Wounds treated on an outpatient basis may be treated with oral antibiotics, whereas wounds requiring admission to the hospital should be treated with intravenous antibiotics.
Prophylaxis in the noninfected wound should be continued for 5-7 days, whereas therapeutic antibiotics should be administered for 10-14 days.
Selection of the appropriate antibiotic involves multiple factors, including culture results if obtained and available, drug sensitivities, patient age, drug interactions, expected compliance, and renal and hepatic function.
Antibiotics
Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.
Amoxicillin and clavulanic acid (Augmentin)
Drug combination treats bacteria resistant to beta-lactam antibiotics. The most effective and economical choice for outpatient therapy unless contraindicated.
In children >3 mo, base dosing protocol on amoxicillin content. Because of different amoxicillin/clavulanic acid ratios in 250-mg tab (250/125) vs 250-mg chewable tab (250/62.5), do not use 250-mg tab until child weighs >40 kg.
Adult
500/125 mg PO tid or 875/125 mg PO bid
Pediatric
40 mg/kg/d PO, divided q8h (based on amoxicillin component)
Probenecid decreases renal excretion, increasing blood levels of amoxicillin; coadministration with warfarin or heparin, increases risk of bleeding; may decrease effectiveness of oral contraceptive agents
Documented hypersensitivity
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Administer for a minimum of 10 d to eliminate organism and to prevent sequelae (eg, endocarditis, rheumatic fever); following treatment, perform cultures to confirm eradication of streptococci; renal insufficiency may require dose reduction
Doxycycline (Doryx, Vibramycin, Vibra-Tabs)
Alternative for oral therapy in the penicillin-allergic patient. Inhibits protein synthesis and thus bacterial growth by binding to 30S and possibly 50S ribosomal subunits of susceptible bacteria.
Adult
100 mg PO bid
Pediatric
<8 years: Not established
>8 years: 2-4 mg/kg/d PO divided q12h
Bioavailability decreases with antacids containing aluminum, calcium, magnesium, iron, or bismuth subsalicylate; tetracyclines can increase hypoprothrombinemic effects of anticoagulants; tetracyclines can decrease effects of oral contraceptives, causing breakthrough bleeding and increased risk of pregnancy
Documented hypersensitivity; severe hepatic dysfunction; lactation
Pregnancy
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Precautions
Caution in patients who are cachectic or debilitated and in hepatic or renal disease; photosensitivity may occur with prolonged exposure to sunlight or tanning equipment; reduce dose in renal impairment; consider drug serum level determinations in prolonged therapy; tetracycline use during tooth development (last half of pregnancy through age 8 y) can cause permanent discoloration of teeth; Fanconilike syndrome may occur with outdated tetracyclines
Ceftriaxone sodium (Rocephin)
Third-generation cephalosporin with broad-spectrum, gram-negative activity; lower efficacy against gram-positive organisms; higher efficacy against resistant organisms. Arrests bacterial growth by binding to one or more penicillin-binding proteins. Once-daily IM dosing may benefit the noncompliant patient. Also may be used as an IV antibiotic for patients admitted to the hospital.
Adult
1 g IV/IM qd
Pediatric
50 mg/kg/d IV/IM qd
Probenecid may increase ceftriaxone levels; coadministration with ethacrynic acid, furosemide, and aminoglycosides may increase nephrotoxicity
Documented hypersensitivity
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Adjust dose in renal impairment; caution in breastfeeding women and allergy to penicillin
Cefoxitin sodium (Mefoxin)
Second-generation cephalosporin indicated for gram-positive cocci and gram-negative rod infections. Infections caused by cephalosporin- or penicillin-resistant gram-negative bacteria may respond to cefoxitin.
Adult
1-2 g IV q4-8h
Pediatric
25-50 mg/kg/d IV divided q6h
Probenecid may increase effects of cefoxitin; coadministration with aminoglycosides or furosemide may increase nephrotoxicity (closely monitor renal function)
Documented hypersensitivity
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Bacterial or fungal overgrowth of nonsusceptible organisms may occur with prolonged use or repeated treatment; caution in patients with previously diagnosed colitis
Ampicillin sodium and sulbactam (Unasyn)
Drug combination of beta-lactamase inhibitor with ampicillin. Covers skin, enteric flora, and anaerobes. Not ideal for nosocomial pathogens.
Adult
1.5 (1 g ampicillin + 0.5 g sulbactam) to 3.0 g (2 g ampicillin + 1 g sulbactam) IV/IM q6-8h; not to exceed 4 g/d sulbactam or 8 g/d ampicillin
Pediatric
<12 years: Not established
>12 years: Administer as in adults
Probenecid and disulfiram elevate ampicillin levels; allopurinol decreases ampicillin effects and has additive effects on ampicillin rash; may decrease effects of oral contraceptives
Documented hypersensitivity
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Adjust dose in renal failure; evaluate rash and differentiate from hypersensitivity reaction
Ticarcillin disodium and clavulanic acid (Timentin)
Inhibits biosynthesis of cell wall mucopeptide and is effective during stage of active growth.
Adult
3.1 g IV q6h
Pediatric
<12 years: Not established
>12 years: Administer as in adults
Tetracyclines may decrease effects of ticarcillin; high concentrations of ticarcillin may physically inactivate aminoglycosides if administered in same IV line; effects when administered concurrently with aminoglycosides are synergistic; probenecid may increase penicillin levels
Documented hypersensitivity; severe pneumonia, bacteremia, pericarditis, emphysema, meningitis, and purulent or septic arthritis should not be treated with oral penicillin during acute stage
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Perform CBCs prior to initiation of therapy and at least weekly during therapy; monitor for liver function abnormalities by measuring AST and ALT during therapy; exercise caution in patients diagnosed with hepatic insufficiencies; perform urinalysis, BUN, and creatinine determinations during therapy, and adjust dose if values become elevated; monitor blood levels to avoid possible neurotoxic reactions
More on Human Bite Infections |
| Overview: Human Bite Infections |
| Differential Diagnoses & Workup: Human Bite Infections |
 Treatment & Medication: Human Bite Infections |
| Follow-up: Human Bite Infections |
| References |
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References
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Further Reading
Keywords
human bite infections, human bites, infection, oral flora, saliva, hand wounds, clenched-fist injury, occlusive bites, hepatitis B, hepatitis C, herpes simplex virus, HSV, syphilis, tuberculosis, actinomycosis, tetanus, HIV, AIDS, Eikenella corrodens, E corrodens, Staphylococcus aureus, S aureus, Clostridium tetani, C tetani, Streptococcus, Corynebacterium, Bacteroides, Peptostreptococcus, bacteremia, sepsis
