What is the recommended antibiotic for facial cellulitis?

Recommended Antibiotic for Facial Cellulitis

For typical facial cellulitis without purulent drainage or MRSA risk factors, use beta-lactam monotherapy with either oral cephalexin, dicloxacillin, or amoxicillin for 5 days, as this achieves 96% success rates and MRSA coverage is unnecessary in most cases. 1

First-Line Treatment Selection

Standard Oral Regimens for Uncomplicated Facial Cellulitis

• Cephalexin 500 mg orally four times daily is the preferred first-line agent for typical nonpurulent facial cellulitis 1
• Dicloxacillin 250-500 mg orally every 6 hours provides excellent streptococcal and methicillin-sensitive S. aureus coverage 1
• Amoxicillin alone is appropriate and provides adequate streptococcal coverage for typical cases 1
• Penicillin V 250-500 mg orally four times daily is an alternative option 1

The Infectious Diseases Society of America establishes that beta-lactam monotherapy is the standard of care because MRSA is an uncommon cause of typical cellulitis, even in high-prevalence settings 1. Treatment duration should be exactly 5 days if clinical improvement occurs, extending only if symptoms have not improved within this timeframe 1.

When MRSA Coverage IS Required

Add MRSA-active antibiotics only when specific risk factors are present 1:

• Penetrating trauma or injection drug use 1
• Purulent drainage or exudate 1
• Evidence of MRSA infection elsewhere or known MRSA colonization 1
• Systemic inflammatory response syndrome (SIRS) 1
• Failure to respond to beta-lactam therapy after 48 hours 1

For MRSA coverage, use clindamycin 300-450 mg orally every 6 hours as monotherapy, which covers both streptococci and MRSA, avoiding the need for combination therapy 1. However, clindamycin should only be used if local MRSA resistance rates are <10% 1.

Alternative MRSA regimens include:

• Trimethoprim-sulfamethoxazole PLUS a beta-lactam (such as cephalexin) 1
• Doxycycline 100 mg orally twice daily PLUS a beta-lactam (only in patients >8 years old) 1

Critical pitfall: Never use doxycycline or trimethoprim-sulfamethoxazole as monotherapy for facial cellulitis, as their activity against beta-hemolytic streptococci is unreliable 1.

Special Considerations for Facial Cellulitis

Preseptal (Periorbital) Cellulitis

For facial cellulitis involving the eyelid (preseptal cellulitis):

• First-line outpatient treatment: Amoxicillin-clavulanate provides broader coverage for mixed infections 2
• Alternative options: Cephalexin or dicloxacillin if S. aureus coverage is desired 2
• Daily follow-up is mandatory until definite improvement is noted 2
• Hospitalize immediately if proptosis, impaired visual acuity, or impaired/painful extraocular mobility develops, as these indicate orbital involvement requiring IV antibiotics 2

Odontogenic (Dental) Facial Cellulitis

For facial cellulitis of dental origin:

• Amoxicillin-clavulanate 875/125 mg orally twice daily is preferred as monotherapy because it provides single-agent coverage for polymicrobial oral flora 1
• Dental abscesses are polymicrobial aerobic/anaerobic infections requiring surgical drainage plus antibiotics 3
• Clindamycin is equally effective and covers the anaerobes commonly found in dental infections 3

Inpatient IV Therapy for Severe Facial Cellulitis

Hospitalize if any of the following are present 1:

• Systemic inflammatory response syndrome (fever, tachycardia, tachypnea)
• Hypotension or altered mental status
• Severe immunocompromise or neutropenia
• Concern for deeper or necrotizing infection

IV Antibiotic Selection

For hospitalized patients without MRSA risk factors:

• Cefazolin 1-2 g IV every 8 hours is the preferred IV beta-lactam 1
• Nafcillin 2 g IV every 6 hours or oxacillin 2 g IV every 6 hours are alternatives 1

For hospitalized patients requiring MRSA coverage:

• Vancomycin 15-20 mg/kg IV every 8-12 hours is first-line (A-I evidence) 1
• Linezolid 600 mg IV twice daily is equally effective (A-I evidence) 1
• Daptomycin 4 mg/kg IV once daily is an alternative (A-I evidence) 1, 4
• Clindamycin 600 mg IV every 8 hours if local resistance is <10% 1

For severe facial cellulitis with systemic toxicity or suspected necrotizing fasciitis, use mandatory broad-spectrum combination therapy 1:

• Vancomycin 15-20 mg/kg IV every 8-12 hours PLUS piperacillin-tazobactam 3.375-4.5 g IV every 6 hours 1
• Alternative: Linezolid PLUS piperacillin-tazobactam 1

Patients can transition to oral antibiotics once clinical improvement is demonstrated, typically after a minimum of 4 days of IV treatment 1.

Common Pitfalls to Avoid

• Do not routinely add MRSA coverage for typical facial cellulitis without specific risk factors—this represents overtreatment and increases antibiotic resistance 1
• Do not use combination therapy (such as adding trimethoprim-sulfamethoxazole to cephalexin) when monotherapy is appropriate, as this provides no additional benefit in pure cellulitis 1, 5
• Do not delay hospitalization if there is any concern for orbital involvement in preseptal cellulitis or if outpatient therapy fails within 24-48 hours 2
• Do not continue ineffective antibiotics beyond 48 hours—progression despite appropriate therapy indicates either resistant organisms or a deeper/different infection 1

Adjunctive Measures

• Elevation of the head (if lower facial cellulitis) promotes drainage and hastens improvement 1
• Assess for abscess with ultrasound if there is any clinical uncertainty, as purulent collections require incision and drainage plus MRSA-active antibiotics 1
• Systemic corticosteroids (prednisone 40 mg daily for 7 days) could be considered in non-diabetic adults, though evidence is limited 1