Cephalexin vs Augmentin for Preseptal Cellulitis
For preseptal cellulitis in children, cephalexin is the preferred first-line oral antibiotic, providing adequate coverage against the typical pathogens (Streptococcus pyogenes and methicillin-sensitive Staphylococcus aureus) that cause this infection in most cases. 1
Treatment Algorithm for Preseptal Cellulitis
Mild Preseptal Cellulitis (Eyelid <50% Closed)
First-Line Therapy:
- Cephalexin is the preferred beta-lactam monotherapy for uncomplicated preseptal cellulitis, as beta-lactam antibiotics successfully treat 96% of typical cellulitis cases 1
- Standard dosing: Cephalexin 25-50 mg/kg/day divided into 3-4 doses for children 1
- Treatment duration: 5 days if clinical improvement occurs, extending only if symptoms persist 1, 2
When Augmentin (Amoxicillin-Clavulanate) is Appropriate:
- High-dose amoxicillin-clavulanate should be used for preseptal cellulitis associated with acute bacterial sinusitis, as sinusitis is a common risk factor in children 2, 3
- Augmentin provides comprehensive coverage when sinusitis is the inciting event, which occurred in 17 of 35 cases (49%) in one pediatric series 4
- Dosing: High-dose amoxicillin-clavulanate (80-90 mg/kg/day of amoxicillin component) 2
Clinical Decision Points
Choose Cephalexin when:
- Preseptal cellulitis follows local trauma, insect bites, or impetigo 5
- No associated sinusitis or upper respiratory symptoms 5
- Patient is older than 36 months without systemic symptoms 5
Choose Augmentin when:
- Associated acute bacterial sinusitis is present (fever, purulent rhinorrhea, facial pain) 2, 3
- Patient has odontogenic infection as the source 3
- Child is under 36 months with upper respiratory symptoms, as Haemophilus influenzae becomes a concern 5
Special Considerations for Young Children
In children under 36 months with upper respiratory symptoms:
- Haemophilus influenzae is the most commonly implicated pathogen in this age group 5
- These children are at risk of bacteremia and metastatic infection 5
- Augmentin provides superior coverage against H. influenzae compared to cephalexin 2, 5
- 12 of 15 children (80%) with preseptal cellulitis and upper respiratory symptoms in one series were under 36 months 5
Indications for Hospitalization and IV Therapy
Admit for IV antibiotics if:
- Eyelid is >50% closed 2
- Proptosis, impaired visual acuity, or painful/impaired extraocular mobility is present 2
- No improvement within 24-48 hours of oral therapy 2
- Systemic toxicity (fever, altered mental status, hypotension) 1
IV regimen for hospitalized patients:
- Cefotaxime plus fosfomycin was used in 35 of 38 children in one series, with mean IV duration of 3 days 4
- Alternative: Ceftriaxone (used in 54.4% of cases) or clindamycin (used in 72.8% of cases) 3
- Transition to oral amoxicillin-clavulanate or cephalexin once clinical improvement is demonstrated 4
MRSA Coverage Considerations
MRSA coverage is NOT routinely necessary for preseptal cellulitis unless specific risk factors are present 1:
- Penetrating trauma or injection drug use
- Purulent drainage or exudate
- Known MRSA colonization
- Failure of beta-lactam therapy after 48-72 hours
If MRSA coverage is needed:
- Clindamycin 10-13 mg/kg/dose orally every 6-8 hours provides coverage for both streptococci and MRSA 1
- Clindamycin was the most commonly used antibiotic (72.8%) in one recent pediatric series 3
Common Pitfalls to Avoid
- Do not reflexively use Augmentin for all preseptal cellulitis—cephalexin is adequate for most cases without sinusitis 1
- Do not delay hospitalization if the child fails to improve within 24-48 hours, as progression to orbital cellulitis can occur 2
- Do not use doxycycline or trimethoprim-sulfamethoxazole as monotherapy in children, as their activity against beta-hemolytic streptococci is unreliable 1
- Always assess for retroseptal (orbital) involvement with CT scan if proptosis, vision changes, or ophthalmoplegia are present 2, 4