What is the appropriate treatment for preseptal cellulitis?

Treatment of Preseptal Cellulitis

Oral beta-lactam antibiotics—specifically cephalexin 500 mg every 6 hours or amoxicillin-clavulanate 875/125 mg twice daily for 5 days—are the first-line treatment for uncomplicated preseptal cellulitis in otherwise healthy patients, achieving approximately 96% clinical success. 1

First-Line Antibiotic Selection

Beta-lactam monotherapy is the standard of care because the primary pathogens in preseptal cellulitis are beta-hemolytic streptococci (especially Streptococcus pyogenes) and methicillin-sensitive Staphylococcus aureus. 1, 2

Recommended Oral Regimens (Adults)

• Cephalexin 500 mg orally every 6 hours for 5 days provides excellent streptococcal and MSSA coverage 1
• Amoxicillin-clavulanate 875/125 mg orally twice daily for 5 days offers broader polymicrobial coverage, particularly useful when sinusitis is the predisposing factor 1
• Dicloxacillin 250-500 mg orally every 6 hours for 5 days is an equally effective alternative 1, 3

Pediatric Dosing

• Cephalexin 25-50 mg/kg/day divided every 6 hours for children with uncomplicated preseptal cellulitis 1
• Amoxicillin-clavulanate at standard pediatric dosing is appropriate when broader coverage is needed 1

Treatment Duration

Treat for exactly 5 days if clinical improvement occurs (reduced warmth, tenderness, periorbital edema, and absence of fever); extend only if symptoms have not improved within this timeframe. 1 High-quality randomized controlled trial evidence demonstrates that 5-day courses are as effective as 10-day courses for uncomplicated cellulitis. 1

When to Add MRSA Coverage

Routine MRSA-active antibiotics are unnecessary for typical preseptal cellulitis because MRSA is an uncommon cause even in high-prevalence settings. 1

Add MRSA coverage only when specific risk factors are present:

• Penetrating trauma to the periorbital area 1
• Purulent drainage or exudate from the infection site 1
• Known MRSA colonization or prior MRSA infection 1
• Systemic inflammatory response syndrome (fever >38°C, tachycardia, tachypnea) 1
• Failure to respond to beta-lactam therapy after 48-72 hours 1

MRSA-Active Regimens When Indicated

• Clindamycin 300-450 mg orally every 6 hours provides single-agent coverage for both streptococci and MRSA, but use only if local MRSA clindamycin resistance is <10% 1
• Trimethoprim-sulfamethoxazole 1-2 double-strength tablets twice daily PLUS a beta-lactam (cephalexin or amoxicillin) ensures dual coverage 1
• Doxycycline 100 mg orally twice daily PLUS a beta-lactam is an alternative combination, but contraindicated in children <8 years and pregnant women 1

Hospitalization Criteria and Intravenous Therapy

Admit patients with preseptal cellulitis when any of the following are present:

• Age <6 months with moderate-to-severe disease 1
• Systemic inflammatory response syndrome (fever, tachycardia, hypotension, altered mental status) 1, 4
• Signs suggesting progression to orbital cellulitis: diplopia, ophthalmoplegia, proptosis, or severe pain with eye movement 4
• Concern for deeper infection or complications 1, 5
• Severe immunocompromise or neutropenia 1

Intravenous Antibiotic Regimens

• Cefazolin 1-2 g IV every 8 hours (adults) or weight-based dosing for children is the preferred IV beta-lactam for hospitalized patients without MRSA risk factors 1
• Vancomycin 15-20 mg/kg IV every 8-12 hours (adults) or 15 mg/kg IV every 6 hours (children) for MRSA coverage when risk factors are present 1
• For severe infections with systemic toxicity: vancomycin PLUS piperacillin-tazobactam 3.375-4.5 g IV every 6 hours provides broad-spectrum coverage 1

Treatment duration for hospitalized patients is typically 7-14 days, individualized based on clinical response. 1, 5

Imaging and Diagnostic Considerations

CT scan is indicated when:

• Clinical examination cannot reliably distinguish preseptal from orbital cellulitis 4
• Diplopia, ophthalmoplegia, proptosis, or severe pain with eye movement is present 4
• No clinical improvement after 48-72 hours of appropriate antibiotics 4
• Concern for abscess formation or intracranial extension 4

C-reactive protein >120 mg/L strongly suggests orbital rather than preseptal involvement and warrants imaging. 4

Key Differential Features: Preseptal vs. Orbital Cellulitis

Preseptal cellulitis presents with:

• Periorbital edema and erythema without globe involvement 5, 4
• Normal extraocular movements and visual acuity 3, 4
• Lower median CRP (typically <50 mg/L) 4
• Less frequent fever (51.5% of cases) 4

Orbital cellulitis presents with:

• Diplopia, ophthalmoplegia, or proptosis 4
• Pain with eye movement 4
• Higher median CRP (typically >120 mg/L) 4
• More frequent fever (82.2% of cases) and preexisting sinusitis (77.8%) 4

Adjunctive Measures

• Elevate the head of the bed to promote gravity drainage of periorbital edema 1
• Treat predisposing conditions such as sinusitis, which is present in 52.9% of pediatric cases with identifiable risk factors 5
• Warm compresses may provide symptomatic relief 6
• Ibuprofen or acetaminophen for pain control, aligning with the typical 5-day antibiotic course 7

Critical Pitfalls to Avoid

• Do not delay treatment while awaiting culture results; preseptal cellulitis can progress rapidly to orbital involvement or intracranial complications 5, 2
• Do not use doxycycline or trimethoprim-sulfamethoxazole as monotherapy for typical preseptal cellulitis because they lack reliable activity against beta-hemolytic streptococci 1
• Do not add MRSA coverage reflexively without specific risk factors, as this overtreats the majority of cases and promotes resistance 1
• Do not miss progression to orbital cellulitis; reassess patients within 24-48 hours to verify clinical response 1, 4
• Consider alternate pathogens (including gram-negative organisms like Proteus species) when patients fail to respond to initial beta-lactam therapy 3

Special Populations

In immunocompromised adults (such as patients with malignancy), preseptal cellulitis caused by Streptococcus pyogenes can be complicated by streptococcal toxic shock syndrome and metastatic abscesses. 2 These patients require:

• Immediate hospitalization and IV antibiotics 2
• Close monitoring for systemic complications 2
• Consideration of surgical debridement if abscesses develop 2

Corticosteroids (prednisone 40 mg daily for 7 days) could be considered in non-diabetic adults with severe inflammation, though evidence is limited and this should not replace appropriate antibiotic therapy. 7 Corticosteroids are contraindicated in diabetic patients. 7