What is the treatment for a foot wound with swelling and pus?

Treatment of Infected Foot Wound with Swelling and Pus

This infected foot wound requires immediate antibiotic therapy combined with urgent surgical debridement, proper wound care, and pressure offloading—antibiotics alone are insufficient without addressing the wound itself. 1

Immediate Assessment and Severity Classification

Diagnose infection clinically by the presence of purulent discharge (which you have) plus at least two signs of inflammation: redness, warmth, swelling, or pain. 1

Classify the infection severity immediately: 1

• Mild: Superficial with minimal cellulitis (<2 cm surrounding erythema)
• Moderate: Deeper infection or more extensive cellulitis (>2 cm)
• Severe: Systemic signs (fever, elevated white blood cell count, hypotension) or deep tissue involvement

Check vital signs and obtain blood tests including white blood cell count and C-reactive protein—an elevated white blood cell count indicates severe infection even without fever. 2

Probe the wound with a sterile metal probe to assess depth and determine if bone is palpable, which suggests osteomyelitis. 1

Urgent Surgical Intervention

Seek immediate surgical consultation for: 1

• Deep abscess (likely given the pus accumulation)
• Extensive necrosis or gangrene
• Necrotizing fasciitis
• Bone or joint involvement
• Compartment syndrome

Perform urgent debridement to remove all necrotic tissue, callus, and purulent material—this is the single most important factor influencing healing and cannot be compensated for by antibiotics alone. 1 Sharp debridement with scalpel or scissors is preferable to other methods. 1

Obtain tissue specimens (not swabs) from the debrided wound base for culture and sensitivity testing before starting antibiotics. 1, 3

Antibiotic Therapy

Start empirical antibiotics immediately after obtaining cultures: 1

For mild-to-moderate infections without recent antibiotic use:

• Oral antibiotics targeting aerobic gram-positive cocci (Staphylococcus aureus, Streptococcus) are sufficient 1
• Options include flucloxacillin, cephalexin, or clindamycin 1
• Highly bioavailable oral antibiotics can be used for most mild and many moderate infections 1

For severe infections or recent antibiotic exposure:

• Start parenteral (IV) broad-spectrum antibiotics initially 1
• Consider local MRSA prevalence when selecting empirical therapy 1
• Switch to oral therapy once infection is responding 1

Duration of antibiotic therapy: 1

• Mild infections: 1-2 weeks
• Moderate-to-severe infections: 2-4 weeks
• Continue until infection resolves, not necessarily until wound heals 1

Essential Wound Care

Proper wound care is crucial and must accompany antibiotic therapy: 1

1. Debride thoroughly to remove all callus, necrotic tissue, and purulent material 1
2. Irrigate copiously with lavage solution under moderate pressure 4
3. Apply appropriate dressing that allows daily inspection and maintains moist wound environment 1
4. Off-load pressure completely—this is a cornerstone of treatment and as important as antibiotics 1

For plantar foot wounds, use a non-removable knee-high offloading device (total contact cast or irremovable walker) as the preferred method. 1

Vascular Assessment

Evaluate arterial perfusion immediately: 1

• Check for palpable pulses
• Measure ankle-brachial index (ABI) and toe pressures
• If toe pressure <30 mmHg or TcpO₂ <25 mmHg, consider urgent revascularization 1
• For severely infected ischemic foot, perform revascularization within 1-2 days rather than relying on prolonged antibiotic therapy alone 1

Follow-Up and Monitoring

Require early and careful follow-up observation to ensure treatment effectiveness. 1

If the infection fails to respond after one antibiotic course in a clinically stable patient, discontinue all antimicrobials for a few days, then obtain optimal culture specimens. 1

Reassess wounds not showing healing signs within 6 weeks despite optimal management—consider revascularization regardless of initial vascular test results. 1

Critical Pitfalls to Avoid

Do not rely on antibiotics alone—wound care, debridement, and pressure offloading are equally essential and antibiotics are often insufficient without these interventions. 1

Do not use superficial wound swabs for culture—obtain deep tissue specimens from the wound base after debridement for accurate pathogen identification. 1, 3

Do not delay surgical debridement while waiting for antibiotic response—necrotic tissue removal should occur urgently. 1

Do not close infected wounds prematurely—allow healing by secondary intention or delayed closure rather than risk dehiscence and worsening infection. 4