What is the recommended treatment for cellulitis of the ear?

Treatment of Cellulitis of the Ear

Recommended Antibiotic Therapy

For cellulitis of the ear, treat with oral beta-lactam monotherapy such as cephalexin 500 mg four times daily, dicloxacillin 250-500 mg every 6 hours, or amoxicillin for 5 days, extending only if symptoms have not improved within this timeframe. 1

First-Line Treatment Selection

• Beta-lactam monotherapy is the standard of care for typical uncomplicated cellulitis, with a 96% success rate, confirming that MRSA coverage is usually unnecessary 1, 2
• Recommended oral agents include penicillin, amoxicillin, amoxicillin-clavulanate, dicloxacillin, cephalexin, or clindamycin 1
• The majority of cellulitis cases are caused by β-hemolytic streptococci and methicillin-sensitive Staphylococcus aureus when organisms are identified 2, 3

Treatment Duration

• Treat for exactly 5 days if clinical improvement occurs, with extension only if symptoms have not improved within this timeframe 1, 4
• Traditional 7-14 day courses are no longer necessary for uncomplicated cases 1
• Patients should show improvement within 24-48 hours of appropriate antibiotic therapy 4

When to Add MRSA Coverage

Add MRSA-active antibiotics ONLY when specific risk factors are present:

• Penetrating trauma to the ear 1, 4
• Purulent drainage or exudate 1, 4
• Evidence of MRSA infection elsewhere or nasal MRSA colonization 1, 4
• Injection drug use 1
• Systemic inflammatory response syndrome (SIRS) 1

MRSA-Active Regimens (When Indicated)

• Clindamycin 300-450 mg orally every 6 hours provides single-agent coverage for both streptococci and MRSA, avoiding the need for combination therapy 1, 4
• Alternative: Trimethoprim-sulfamethoxazole plus a beta-lactam, or doxycycline plus a beta-lactam 1
• Never use doxycycline or trimethoprim-sulfamethoxazole as monotherapy for typical cellulitis, as their activity against beta-hemolytic streptococci is unreliable 1

Penicillin Allergy Considerations

• For penicillin-allergic patients with typical cellulitis, use clindamycin or erythromycin 4
• Clindamycin is preferred as it covers both streptococci and MRSA 1, 4

Severe Infections Requiring Hospitalization

Hospitalize if any of the following are present:

• Systemic inflammatory response syndrome (SIRS): fever >38°C, tachycardia >90 bpm, tachypnea >24 rpm 1
• Altered mental status or hemodynamic instability 4
• Concern for deeper infection or necrotizing fasciitis 4
• Severe immunocompromise or neutropenia 1
• Failed outpatient treatment 4

Inpatient IV Antibiotic Regimens

• Vancomycin 15-20 mg/kg IV every 8-12 hours is first-line for hospitalized patients with complicated cellulitis (A-I evidence) 1
• Alternative IV agents include linezolid 600 mg IV twice daily, daptomycin 4 mg/kg IV once daily, or clindamycin 600 mg IV three times daily if local resistance is low 1
• For severe cellulitis with systemic toxicity or suspected necrotizing fasciitis, use vancomycin plus piperacillin-tazobactam 3.375-4.5 g IV every 6 hours 1

Adjunctive Measures

• Elevation of the affected area promotes gravity drainage of edema and hastens improvement 1, 4
• Consider systemic corticosteroids (prednisone 40 mg daily for 7 days) in non-diabetic adults, though evidence is limited 1, 4
• Treat predisposing conditions such as edema, eczema, and chronic skin conditions 1

Critical Pitfalls to Avoid

• Do not routinely add MRSA coverage for typical nonpurulent cellulitis without specific risk factors—this represents overtreatment and increases antibiotic resistance 1
• Do not use combination therapy (SMX-TMP plus cephalexin) for pure cellulitis without abscess, ulcer, or purulent drainage, as it provides no additional benefit 1
• Do not continue ineffective antibiotics beyond 48 hours—progression despite appropriate therapy indicates either resistant organisms or a deeper/different infection 1
• If no improvement within 72 hours, consider changing antibiotics, imaging to rule out abscess formation, or hospital admission for IV antibiotics 4

Special Considerations for Ear Cellulitis

While the general principles above apply, ear cellulitis warrants particular attention to:

• Rule out perichondritis (infection of the cartilage), which requires more aggressive treatment and may need antipseudomonal coverage if suspected
• Assess for associated otitis externa or media that may require additional management
• Monitor closely for progression given the proximity to critical structures