What is the recommended dose of amoxicillin (amoxicillin-clavulanate) for preorbital cellulitis?

Amoxicillin-Clavulanate Dosing for Periorbital Cellulitis

For periorbital cellulitis, high-dose amoxicillin-clavulanate is recommended at 45 mg/kg/day divided every 12 hours for children or 875 mg/125 mg every 12 hours for adults. 1, 2

Classification and Pathophysiology

Periorbital (preseptal) cellulitis is an infection of the eyelid and surrounding soft tissues anterior to the orbital septum, distinct from the more serious orbital (postseptal) cellulitis which involves tissues behind the septum.

• Common causes:
  • Sinusitis (most common, especially ethmoid sinusitis) 3, 4
  • Local trauma or skin infection
  • Upper respiratory tract infection
  • Odontogenic infection

Antibiotic Selection

First-line therapy:

• High-dose amoxicillin-clavulanate:
  • Children: 45 mg/kg/day divided every 12 hours (based on amoxicillin component) 1
  • Adults: 875 mg/125 mg every 12 hours 2

Amoxicillin-clavulanate is preferred because:

1. It provides coverage against both beta-hemolytic streptococci and Staphylococcus aureus
2. The addition of clavulanate protects against beta-lactamase producing organisms
3. It has good penetration into sinus and orbital tissues

Alternative options (for penicillin allergies):

• Clindamycin: Provides good coverage for both streptococci and MRSA 5

  • Adults: 600 mg PO three times daily
  • Children: 30-40 mg/kg/day divided three times daily

• Combination therapy: If MRSA is a concern, consider:

  • Trimethoprim-sulfamethoxazole (for MRSA) plus cefuroxime (for streptococci) 1, 5

Treatment Duration and Monitoring

• Duration: 7-10 days, can be shortened to 5 days if rapid clinical improvement occurs 5
• Monitoring: Assess for improvement within 48-72 hours of initiating treatment
• Treatment failure indicators:
  • Worsening symptoms after 72 hours
  • Development of orbital signs (proptosis, limited eye movement, vision changes)
  • Systemic symptoms (high fever, lethargy)

Severity Assessment

Mild periorbital cellulitis (outpatient management):

• Minimal eyelid swelling and erythema
• No systemic symptoms
• No visual disturbances
• No limitation of extraocular movements

Moderate-severe periorbital cellulitis (consider hospitalization):

• Significant eyelid swelling extending beyond the eyelid
• Systemic symptoms (fever, malaise)
• Children under 1 year of age
• Immunocompromised patients
• Inability to tolerate oral medications

Signs of progression to orbital cellulitis (requires immediate IV antibiotics):

• Proptosis
• Ophthalmoplegia (limited eye movement)
• Pain with eye movement
• Decreased visual acuity
• Chemosis (conjunctival swelling)

Special Considerations

• Children: Higher risk of complications; close monitoring required
• Sinusitis-related cases: May require longer treatment course
• Immunocompromised patients: Consider broader coverage and longer duration

Complications and Follow-up

• If no improvement or worsening after 72 hours, consider:

  1. CT scan to evaluate for orbital involvement or abscess
  2. Switching to IV antibiotics
  3. ENT or ophthalmology consultation
  4. Possible surgical drainage if abscess is present

• Common pitfalls:

  1. Failure to distinguish between periorbital and orbital cellulitis
  2. Inadequate dosing of antibiotics
  3. Insufficient duration of therapy
  4. Delayed recognition of treatment failure

Summary

Periorbital cellulitis requires prompt antibiotic therapy to prevent progression to orbital cellulitis. High-dose amoxicillin-clavulanate is the first-line treatment, with careful monitoring for clinical improvement within 48-72 hours. Patients who fail to improve may require hospitalization, IV antibiotics, imaging studies, and possible surgical intervention.