What is the recommended workup and management for a patient presenting with facial cellulitis, considering their medical history and potential complications?

Workup and Management of Facial Cellulitis

Initial Clinical Assessment

For facial cellulitis, begin with beta-lactam monotherapy targeting streptococci (the primary pathogen), reserving MRSA coverage only for specific high-risk features, and treat for 5 days if clinical improvement occurs. 1

Key Diagnostic Features to Identify

• Facial cellulitis presents with expanding erythema, warmth, tenderness, and swelling of the deep dermis and subcutaneous tissue 2, 3
• The diagnosis is primarily clinical—blood cultures, tissue aspirates, or skin biopsies are generally unnecessary for typical cases 2
• Obtain blood cultures only if the patient has malignancy, severe systemic features (high fever >38.5°C, hypotension, heart rate >110 bpm), neutropenia, or severe immunodeficiency 1, 2

Critical Red Flags Requiring Immediate Action

• Assess for preseptal versus orbital cellulitis: Check for proptosis, impaired visual acuity, or painful/impaired extraocular movements, which mandate immediate hospitalization and contrast-enhanced CT 4
• Evaluate for necrotizing fasciitis: Look for severe pain out of proportion to examination, skin anesthesia, rapid progression, gas in tissue, bullous changes, or "wooden-hard" subcutaneous tissues—these require emergent surgical consultation 1
• Check for systemic toxicity: SIRS criteria (fever, tachycardia >90 bpm, tachypnea >24 rpm), hypotension, altered mental status, or confusion mandate hospitalization 1, 2

Antibiotic Selection Algorithm

For Mild to Moderate Facial Cellulitis (Outpatient)

First-line therapy (96% success rate): 1

• Oral penicillin, amoxicillin, dicloxacillin, cephalexin, or clindamycin targeting streptococci 1, 4, 2
• Specific dosing examples: cephalexin 500 mg four times daily, dicloxacillin 250-500 mg every 6 hours, or amoxicillin standard dosing 1
• Duration: 5 days if clinical improvement occurs; extend only if symptoms have not improved 1, 4, 2

For penicillin-allergic patients: 4

• Clindamycin 300-450 mg orally every 6 hours (covers both streptococci and MRSA) 1, 4
• Erythromycin as alternative 4

When to Add MRSA Coverage

MRSA coverage is NOT routinely necessary for typical facial cellulitis, as MRSA is an uncommon cause even in high-prevalence settings 1, 2. Add MRSA-active therapy only when specific risk factors are present: 1, 4, 2

• Penetrating trauma to the face 1, 4
• Purulent drainage or exudate 1, 4
• Evidence of MRSA infection elsewhere or nasal MRSA colonization 4, 2
• Injection drug use 1, 4
• Failed initial beta-lactam therapy 2

MRSA-active oral regimens when indicated: 1

• Clindamycin 300-450 mg every 6 hours (monotherapy—covers both streptococci and MRSA) 1, 4
• Doxycycline 100 mg twice daily PLUS a beta-lactam (never doxycycline alone, as it lacks reliable streptococcal coverage) 1
• Trimethoprim-sulfamethoxazole PLUS a beta-lactam 1

For Severe Facial Cellulitis (Inpatient)

Hospitalization criteria: 4, 2

• Systemic inflammatory response syndrome (SIRS) 1, 4, 2
• Altered mental status or hemodynamic instability 4, 2
• Concern for deeper infection or orbital involvement 4, 2
• Immunocompromised status 4, 2
• Failed outpatient treatment 4

Intravenous antibiotic regimens: 1, 2

• For typical severe cellulitis without MRSA risk factors: Cefazolin 1-2 g IV every 8 hours or oxacillin 2 g IV every 6 hours 1
• For severe cellulitis with MRSA risk factors: Vancomycin 15-20 mg/kg IV every 8-12 hours (first-line, A-I evidence) 1, 2
• Alternatives to vancomycin: Linezolid 600 mg IV twice daily, daptomycin 4 mg/kg IV once daily, or clindamycin 600 mg IV every 8 hours (if local MRSA resistance <10%) 1, 2

For suspected necrotizing fasciitis or systemic toxicity: 1

• Mandatory broad-spectrum combination therapy: Vancomycin or linezolid PLUS piperacillin-tazobactam 3.375-4.5 g IV every 6 hours 1
• Alternative combinations: Vancomycin PLUS a carbapenem, or vancomycin PLUS ceftriaxone and metronidazole 1
• Duration: 7-14 days for severe infections, guided by clinical response 1

Special Considerations for Preseptal Cellulitis

Preseptal cellulitis (eyelid involvement without orbital signs): 4

• First-line: Oral penicillin, amoxicillin, dicloxacillin, or cephalexin for 5 days 4
• If associated with acute bacterial sinusitis: High-dose amoxicillin-clavulanate 4
• Hospitalize if: No improvement within 24-48 hours, progressive infection, or any signs of orbital involvement (proptosis, visual changes, painful eye movements) 4
• For hospitalized cases: Vancomycin to cover possible methicillin-resistant S. pneumoniae 4
• Consult ophthalmology, otolaryngology, and infectious disease for guidance on surgical intervention if orbital involvement suspected 4

Adjunctive Measures

Essential non-antibiotic interventions: 1, 4, 2

• Elevate the affected area (head of bed elevated for facial cellulitis) to promote gravity drainage of edema—this hastens improvement and is often neglected 1, 4, 2
• Consider systemic corticosteroids (prednisone 40 mg daily for 7 days) in non-diabetic adults to hasten resolution, though evidence is limited 1, 4
• Treat predisposing conditions: Address chronic edema, venous insufficiency, eczema, or any skin barrier disruption 1, 2

Monitoring and Follow-Up

• Patients should show improvement within 24-48 hours of appropriate antibiotic therapy 4
• Mandatory reassessment at 48-72 hours to verify clinical response 1, 4
• If no improvement within 72 hours: Consider changing antibiotics, imaging to rule out abscess or deeper infection, or hospital admission for IV antibiotics 4
• Transition to oral therapy once clinical improvement is demonstrated (typically after minimum 4 days of IV treatment for hospitalized patients) 1

Common Pitfalls to Avoid

• Do not reflexively add MRSA coverage for typical facial cellulitis without specific risk factors—beta-lactam monotherapy succeeds in 96% of cases 1, 2
• Do not use doxycycline or trimethoprim-sulfamethoxazole as monotherapy for facial cellulitis, as their activity against beta-hemolytic streptococci is unreliable 1, 4
• Do not use fluoroquinolones as first-line therapy despite their approval for cellulitis, as they lack adequate streptococcal coverage 4
• Do not extend treatment to 7-14 days based on tradition alone—5 days is sufficient if clinical improvement has occurred 1, 4, 2
• Do not fail to elevate the affected area, which significantly delays improvement 1, 4
• Do not miss orbital cellulitis—any visual changes, proptosis, or painful eye movements require immediate imaging and hospitalization 4

Prevention of Recurrence

• Identify and treat predisposing conditions such as chronic sinusitis, facial edema, or skin barrier disruption 4, 2
• For patients with 3-4 episodes per year despite addressing predisposing factors, consider prophylactic antibiotics (oral penicillin or erythromycin twice daily for 4-52 weeks) 4, 2