What is the appropriate treatment for an infected skin tear, including wound care, antibiotic choice (considering MRSA risk and penicillin allergy), tetanus prophylaxis, and criteria for hospital admission?

Treatment of Infected Skin Tears

Infected skin tears require immediate wound cleansing with antimicrobial solution, gentle debridement of devitalized tissue, application of topical antimicrobials for short periods only, and systemic antibiotics when local or systemic signs of infection are present or extending. 1

Initial Wound Assessment and Care

Wound Cleansing

• Gently cleanse the wound with antimicrobial solution using sterile technique to remove debris and reduce bacterial load 1
• Remove all inorganic residues (foreign bodies) and dead tissue before applying any antiseptic, as antiseptics become inactive in the presence of organic material 2
• Use sterile normal saline for irrigation; avoid antiseptic solutions containing iodine as they may impair healing 3

Wound Management Technique

• Do not deroof intact blisters associated with skin tears; if drainage is needed, pierce at the base with a sterile needle (bevel up) and apply gentle pressure with sterile gauze 1
• Apply a bland emollient such as 50% white soft paraffin and 50% liquid paraffin to support barrier function and encourage re-epithelialization 1
• Use nonadherent dressings to protect the wound 1

Indications for Systemic Antibiotics

When Antibiotics Are Mandatory

Systemic antibiotics should be initiated when any of the following are present:

• Local signs of infection: Extending erythema, purulent drainage, increased warmth, or progressive cellulitis 1
• Systemic signs of infection (SIRS criteria):
  • Temperature >38°C or <36°C 1
  • Heart rate >90 beats/minute 1
  • Respiratory rate >24 breaths/minute 1
  • White blood cell count >12,000 or <4,000 cells/µL 1
• Extending infection of the skin beyond the immediate wound margins 1
• Immunocompromised patients or those with significant comorbidities 1, 4

Antibiotic Selection

For Mild-to-Moderate Infection (Outpatient)

First-line oral regimens targeting streptococci and MSSA:

• Cephalexin 500 mg every 6 hours for 5-10 days 1, 3
• Dicloxacillin 500 mg every 6 hours for 5-10 days 3, 5

For Penicillin Allergy (Non-Anaphylactic)

• Cephalexin may still be used if the allergy is not immediate-type (urticaria, angioedema, bronchospasm, or anaphylaxis) 5

For Penicillin Allergy (Anaphylactic) or MRSA Risk

When MRSA is suspected (injection drug use, known MRSA colonization, or high local prevalence):

• Clindamycin 300-450 mg orally every 6-8 hours for 7-10 days 1, 4, 6
• Trimethoprim-sulfamethoxazole (TMP-SMX) 160/800 mg (one double-strength tablet) twice daily for 7-10 days 4, 6
• Doxycycline 100 mg twice daily for 7-10 days (avoid in pregnancy and children <8 years) 4, 6

For Severe Infection Requiring Hospitalization

Intravenous therapy is indicated when there is SIRS, altered mental status, hemodynamic instability, or concern for deeper infection 1:

• Vancomycin 30 mg/kg/day IV in two divided doses for MRSA coverage 4, 6
• For broader coverage in severely compromised patients: Vancomycin plus piperacillin-tazobactam or vancomycin plus imipenem-meropenem 1

Microbiologic Evaluation

When to Obtain Cultures

• Send bacterial and viral swabs from erosions showing clinical signs of infection 1
• Cultures are recommended for patients with malignancy on chemotherapy, neutropenia, severe immunodeficiency, or when infection fails to respond to initial therapy 1
• Blood cultures should be obtained if bacteremia or sepsis is suspected 1, 4

Tetanus Prophylaxis

Tetanus Assessment

• Evaluate tetanus immunization status for all contaminated wounds, particularly those with dirt, debris, or devitalized tissue 1, 7
• Administer tetanus toxoid booster if the patient has been actively immunized but >5 years have elapsed since last dose for contaminated wounds 1, 7
• For patients without adequate immunization history, consider both tetanus toxoid and tetanus immunoglobulin 1

Critical pitfall: Cleansing and debridement must be performed before tetanus prophylaxis decisions, as wound management is paramount 7

Duration of Antibiotic Therapy

• Standard duration is 5-7 days, but treatment should be extended if infection has not improved within this period 1, 4
• Reassess at 5-7 days; patients with ongoing signs of infection beyond 7 days warrant diagnostic re-evaluation 1, 4

Criteria for Hospital Admission

Hospitalization is recommended when:

• SIRS criteria are present (temperature >38°C, heart rate >90 bpm, respiratory rate >24/min, WBC >12,000 or <4,000) 1
• Altered mental status or hemodynamic instability 1
• Concern for deeper or necrotizing infection 1
• Severe immunocompromise or poor adherence to outpatient therapy 1
• Failure to respond to appropriate outpatient management 1

Adjunctive Measures

• Elevate the affected area to reduce edema and accelerate healing 1, 3
• Treat predisposing factors such as underlying edema, venous insufficiency, or cutaneous disorders 1
• For lower extremity wounds, examine interdigital toe spaces for fissuring, scaling, or maceration; treating these may reduce recurrent infection 1
• Daily washing with antibacterial product can decrease colonization in patients with extensive erosions 1

Common Pitfalls to Avoid

• Do not use topical antimicrobials for prolonged periods; they should only be applied for short durations 1
• Do not close infected wounds; this can lead to abscess formation 3
• Avoid using antiseptics for wound cleansing; use physiological saline or tap water instead 2
• Do not delay systemic antibiotics when local or systemic signs of infection are present 1
• Infection and sepsis are significant risks and major causes of mortality, so vigilance in detecting signs of infection is essential 1