Management of Pre‑Septal (Periorbital) Cellulitis
For uncomplicated pre‑septal cellulitis in children and adults, initiate oral beta‑lactam monotherapy (cephalexin 500 mg every 6 hours or amoxicillin‑clavulanate 875/125 mg twice daily) for 5 days, reserving MRSA coverage only for purulent drainage, penetrating trauma, or treatment failure after 48–72 hours. 1
First‑Line Antibiotic Selection
Oral Therapy for Uncomplicated Cases
- Cephalexin 500 mg orally every 6 hours for 5 days provides excellent coverage of beta‑hemolytic streptococci (especially Streptococcus pyogenes) and methicillin‑sensitive Staphylococcus aureus, the predominant pathogens in pre‑septal cellulitis. 1, 2
- Amoxicillin‑clavulanate 875/125 mg orally twice daily for 5 days is an equally effective alternative, offering broader coverage when beta‑lactamase‑producing organisms are suspected. 1, 2
- Dicloxacillin 250–500 mg orally every 6 hours for 5 days is another first‑line option with comparable efficacy. 1, 2
Pediatric Dosing
- Cephalexin 25–50 mg/kg/day divided every 6 hours (maximum 500 mg per dose) for children with uncomplicated pre‑septal cellulitis. 1
- Amoxicillin‑clavulanate 45 mg/kg/day (amoxicillin component) divided twice daily for pediatric patients. 1
Treatment Duration
- Treat for exactly 5 days when clinical improvement is evident (resolution of warmth, tenderness, decreasing erythema, absence of fever); extend only if symptoms persist beyond this period. 1, 2
- High‑quality randomized controlled trial evidence demonstrates that 5‑day courses achieve 98% clinical resolution at 14 days with no relapses by 28 days, making traditional 7–14‑day regimens unnecessary for uncomplicated cases. 1
When to Add MRSA Coverage
Risk Factors Requiring MRSA‑Active Therapy
Add empiric MRSA coverage only when any of the following are present:
- Purulent drainage or exudate from the periorbital area. 1, 3
- Penetrating trauma (e.g., insect bite, scratch, foreign body). 1, 4
- Known MRSA colonization or prior MRSA infection. 1
- Failure to respond to beta‑lactam therapy after 48–72 hours. 1
- Systemic inflammatory response syndrome (fever >38°C, tachycardia, hypotension). 1, 5
MRSA‑Active Regimens
- Clindamycin 300–450 mg orally every 6 hours (pediatric: 10–13 mg/kg/dose every 6–8 hours, maximum 40 mg/kg/day) provides single‑agent coverage for both streptococci and MRSA, but use only if local MRSA clindamycin resistance is <10%. 1, 3
- Trimethoprim‑sulfamethoxazole 1–2 double‑strength tablets twice daily (pediatric: 4–6 mg/kg/dose based on TMP component twice daily) plus a beta‑lactam (cephalexin or amoxicillin) ensures dual coverage. 1
- Doxycycline 100 mg orally twice daily (pediatric ≥8 years: 2 mg/kg twice daily, maximum 100 mg per dose) plus a beta‑lactam; contraindicated in children <8 years due to tooth discoloration and bone growth effects. 1
Evidence for MRSA in Pre‑Septal Cellulitis
- A prospective study at Texas Children's Hospital found that 67% of periorbital S. aureus infections were MRSA, with 78% caused by USA300 strains and 85% carrying Panton‑Valentine leukocidin (PVL) genes. 3
- However, routine MRSA coverage is unnecessary for typical non‑purulent pre‑septal cellulitis, as beta‑lactam monotherapy achieves ~96% clinical success in the absence of specific risk factors. 1
Hospitalization Criteria
Indications for Inpatient Management
Admit patients with pre‑septal cellulitis when any of the following are present:
- Age <6 months with moderate‑to‑severe disease. 1
- Systemic inflammatory response syndrome (fever >38°C, tachycardia >90 bpm, respiratory rate >24 breaths/min, altered mental status). 1, 5
- Signs of orbital involvement (proptosis, ophthalmoplegia, diplopia, vision changes, pain with eye movement). 5
- Severe immunocompromise or neutropenia. 1, 4
- Failure of outpatient therapy after 24–48 hours. 1
- Concern for deeper infection (abscess, orbital cellulitis, intracranial extension). 1, 6
Intravenous Antibiotic Regimens
- Cefazolin 1–2 g IV every 8 hours (pediatric: 25–50 mg/kg/dose every 8 hours) is the preferred IV beta‑lactam for hospitalized patients without MRSA risk factors. 1
- Vancomycin 15–20 mg/kg IV every 8–12 hours (pediatric: 15 mg/kg every 6 hours) is first‑line for MRSA coverage in hospitalized patients (A‑I evidence). 1, 7
- Vancomycin plus piperacillin‑tazobactam 3.375–4.5 g IV every 6 hours for severe cellulitis with systemic toxicity or suspected necrotizing infection. 1
- Linezolid 600 mg IV twice daily (pediatric <12 years: 10 mg/kg every 8 hours; ≥12 years: 600 mg twice daily) is an alternative MRSA‑active agent (A‑I evidence). 1
Distinguishing Pre‑Septal from Orbital Cellulitis
Clinical Features Favoring Pre‑Septal Cellulitis
- Younger age (mean 3.9 years vs. 7.5 years for orbital cellulitis). 5
- Absence of proptosis, ophthalmoplegia, or diplopia (these findings are exclusive to orbital cellulitis). 5
- Lower C‑reactive protein (median 17.85 mg/L vs. 136.35 mg/L for orbital cellulitis). 5
- Absence of sinusitis (present in only 2% of pre‑septal cases vs. 77.8% of orbital cases). 5
Red‑Flag Findings Requiring Urgent CT Imaging
Obtain immediate CT scan with contrast if any of the following are present:
- Proptosis, ophthalmoplegia, or diplopia. 5
- Vision changes or pain with eye movement. 5
- Severe pain out of proportion to examination. 1
- Fever >38°C with CRP >120 mg/L (this cut‑off has high sensitivity for orbital involvement). 5
- Rapid progression despite 24–48 hours of appropriate antibiotics. 1, 6
Role of Imaging
- CT scan is not routinely required for uncomplicated pre‑septal cellulitis with clear clinical features and no orbital signs. 1, 5
- Early CT imaging (within 24 hours) is performed in 75.6% of suspected orbital cellulitis cases and helps detect complications (abscesses, sinusitis, intracranial extension) at an early stage. 5
Adjunctive Measures
- Elevate the head of the bed to promote gravity drainage of periorbital edema and inflammatory substances. 1, 2
- Apply warm compresses to the affected area several times daily to reduce swelling and discomfort. 6
- Treat predisposing conditions such as sinusitis, upper respiratory infections, or skin trauma to reduce recurrence risk. 1, 5
- Examine for occult abscesses with bedside ultrasound if clinical uncertainty exists; purulent collections require incision and drainage plus MRSA‑active antibiotics. 1, 7
Follow‑Up and Monitoring
- Reassess patients within 24–48 hours to confirm clinical improvement (reduced warmth, tenderness, erythema, and swelling). 1, 6
- If no improvement after 48–72 hours of appropriate therapy, consider:
- Extend antibiotic therapy beyond 5 days only if warmth, tenderness, or erythema persist; residual mild erythema alone does not mandate extension. 1
Common Pitfalls to Avoid
- Do not add MRSA coverage reflexively for typical non‑purulent pre‑septal cellulitis without specific risk factors, as this overtreats ~96% of cases and promotes resistance. 1
- Do not use doxycycline or trimethoprim‑sulfamethoxazole as monotherapy for typical cellulitis, as they lack reliable activity against beta‑hemolytic streptococci. 1
- Do not delay CT imaging when any orbital signs (proptosis, ophthalmoplegia, diplopia, vision changes) are present, as orbital cellulitis can progress rapidly to intracranial complications. 6, 5
- Do not automatically extend therapy to 7–10 days; extend only if clinical improvement has not occurred after the initial 5‑day course. 1
- Do not treat simple abscesses with antibiotics alone; incision and drainage is the primary treatment, with antibiotics serving only an adjunctive role. 1, 7
Special Considerations
Immunocompromised Patients
- Immunocompromising factors (malignancy, HIV/AIDS, diabetes, recent chemotherapy) increase the risk of severe complications, including streptococcal toxic shock syndrome and metastatic abscesses. 4
- Empiric MRSA coverage is mandatory in immunocompromised patients regardless of purulence, as they have specific MRSA risk factors. 1, 4
- Consider broader‑spectrum therapy (vancomycin plus piperacillin‑tazobactam) for severely immunocompromised patients with systemic toxicity. 1
Neonates and Infants
- Neonates with pre‑septal cellulitis require hospitalization and IV antibiotics due to risk of rapid progression and sepsis. 1, 7
- MRSA sepsis in neonates can present with periorbital abscess and orbital cellulitis, requiring vancomycin plus incision and drainage of abscesses. 7