How should I cover a patient with antibiotic therapy exhibiting an abscess versus cellulitis of the mandible currently on Augmentin (amoxicillin-clavulanate)?

Management of Mandibular Abscess vs Cellulitis on Augmentin

For a mandibular abscess, immediately perform incision and drainage as the primary treatment, and add antibiotic coverage for MRSA and anaerobes by switching from Augmentin to clindamycin 600 mg PO three times daily, or adding TMP-SMX/doxycycline plus metronidazole if clindamycin is unavailable. 1, 2

Critical Decision Point: Abscess vs Cellulitis

If abscess is present:

• Surgical drainage is the cornerstone and must not be delayed 1, 2
• The facial location (mandible) is specifically cited as an area difficult to drain that mandates antibiotic therapy in addition to drainage 3
• Augmentin alone is insufficient because it lacks adequate MRSA coverage, which is the predominant pathogen in purulent infections 4

If pure cellulitis (nonpurulent):

• Continue Augmentin if no systemic signs and patient is improving 3
• If not responding to Augmentin after 48-72 hours, add MRSA coverage as this indicates potential CA-MRSA involvement 3

Surgical Management Algorithm

For confirmed abscess:

1. Perform incision and drainage immediately - this is the definitive treatment 1, 2
2. Send purulent material for culture and sensitivity 3
3. Consider root canal therapy if tooth is salvageable, or extraction if non-restorable 1, 2
4. Ultrasound guidance can be used for submasseteric space abscesses to avoid facial scarring 5

Antibiotic Selection for Mandibular Abscess

First-line options (choose one):

• Clindamycin 600 mg PO three times daily - provides both streptococcal and MRSA coverage as monotherapy 3
• TMP-SMX 1-2 DS tablets twice daily PLUS metronidazole 400-500 mg three times daily - covers MRSA and anaerobes 3
• Doxycycline 100 mg twice daily PLUS metronidazole 400-500 mg three times daily - alternative combination for MRSA and anaerobes 3

Duration: 5-10 days, individualized based on clinical response 3

Why Augmentin is Inadequate for Mandibular Abscess

• Augmentin (amoxicillin-clavulanate) provides excellent coverage for streptococci and oral anaerobes but lacks MRSA coverage 5
• Purulent infections (abscesses) are predominantly caused by CA-MRSA, not streptococci 3
• The facial location increases risk of complications and necessitates broader coverage 3

Management for Cellulitis Without Abscess

If nonpurulent cellulitis:

• Continue Augmentin if patient is improving clinically 3
• Monitor for response within 48-72 hours 3
• If no improvement, switch to MRSA-active regimen (clindamycin, TMP-SMX, or doxycycline) 3

If purulent cellulitis (drainage without drainable abscess):

• Switch to MRSA-active therapy immediately 3
• Empirical streptococcal coverage is likely unnecessary in purulent cellulitis 3

Hospitalization Criteria

Admit for IV antibiotics if:

• Signs of systemic illness (fever, malaise, SIRS) 1, 2
• Rapid progression or extensive disease involving multiple sites 3
• Immunocompromised or significant comorbidities 3
• Infection spreading into cervicofacial tissues or deep spaces 1, 2
• Failed outpatient management 3

IV options for hospitalized patients:

• Vancomycin 15-20 mg/kg IV every 8-12 hours 3
• Linezolid 600 mg IV twice daily 3
• Clindamycin 600 mg IV three times daily 3

Common Pitfalls to Avoid

• Do not delay surgical drainage - antibiotics without drainage will fail in true abscesses 1, 2, 6
• Do not continue Augmentin for purulent infections - it lacks MRSA coverage which is the predominant pathogen 3
• Do not use antibiotics as monotherapy for dental abscesses - surgical intervention (drainage, root canal, or extraction) is mandatory 1, 2
• Do not prescribe antibiotics for localized dental abscess without systemic symptoms if adequate drainage can be achieved 1, 2