What is the treatment for preseptal orbital cellulitis?

Treatment of Preseptal Cellulitis

For mild preseptal cellulitis without systemic signs, treat with outpatient high-dose oral amoxicillin-clavulanate and mandate reassessment within 24-48 hours; hospitalize for intravenous antibiotics if moderate-to-severe features are present, including systemic signs, eyelid >50% closed, or inability to adequately examine the eye. 1

Initial Assessment and Risk Stratification

The critical first step is distinguishing preseptal from orbital cellulitis, as misdiagnosis can lead to permanent vision loss or life-threatening complications 1. Key clinical features that exclude orbital involvement and confirm preseptal cellulitis include:

• Infection confined anterior to the orbital septum with periorbital erythema, edema, warmth, and tenderness 1, 2
• Absence of proptosis (a key distinguishing feature) 2
• No ophthalmoplegia or painful extraocular movements 1, 2
• No visual acuity changes 1, 2

If any orbital signs are present (proptosis, impaired eye movements, vision changes), this is orbital cellulitis requiring different management 1.

Outpatient Management Criteria

Outpatient treatment is appropriate when all of the following criteria are met 1:

• Eyelid less than 50% closed 1
• No proptosis or visual changes 1
• No systemic signs of infection (fever, hypotension, altered mental status) 1
• Reliable follow-up available within 24-48 hours 1

Outpatient Antibiotic Regimen

First-line: High-dose oral amoxicillin-clavulanate 1

Alternative options (if penicillin allergy or intolerance): 1

• Cephalexin
• Dicloxacillin
• Clindamycin

Inpatient Management Criteria

Hospitalization with intravenous antibiotics is required for moderate-to-severe preseptal cellulitis when any of the following are present 1:

• Systemic signs of infection (fever, tachycardia, hypotension) 1
• Eyelid more than 50% closed 1
• Inability to adequately examine the eye due to severe swelling 1
• Poor adherence to outpatient therapy anticipated 1
• Uncontrolled diabetes mellitus (higher risk for posterior extension and cerebral complications) 3

Inpatient Antibiotic Regimen

Broad-spectrum IV antibiotics covering typical Gram-positive pathogens 1:

• IV amoxicillin-clavulanate 1
• IV cefazolin 1
• IV ceftriaxone 1

The most commonly isolated pathogen is Staphylococcus aureus 4, though microbiologic yield is often low, especially if prior oral antibiotics were given 5.

MRSA Coverage Considerations

Add MRSA-active antibiotics when any of the following risk factors are present 1:

• Penetrating trauma 1
• History of injection drug use 1
• Purulent drainage 1
• Known MRSA colonization 1
• Previous MRSA infection 1

Community-acquired MRSA has emerged as a significant pathogen, accounting for up to 39% of orbital cellulitis cases in some series 6.

MRSA-active options: 1

• IV: Vancomycin, daptomycin, or linezolid
• Oral: Clindamycin, doxycycline, or trimethoprim-sulfamethoxazole

Imaging Indications

CT orbits with IV contrast is the imaging modality of choice when needed 1, 2. Imaging is not routinely required for straightforward preseptal cellulitis 2, but should be obtained when 1, 2:

• Clinical findings cannot reliably distinguish preseptal from orbital cellulitis 2
• Signs of orbital involvement are present 2
• Failure to improve with antibiotics within 24-48 hours 1
• Inability to adequately examine the eye due to severe swelling 1

CT helps identify underlying sinusitis (the most common predisposing cause in orbital cases), complications such as superior ophthalmic vein thrombosis or cavernous sinus thrombosis, and differentiate preseptal from postseptal cellulitis 1, 4.

Laboratory Testing

Blood cultures are unnecessary for typical uncomplicated preseptal cellulitis, as the positive rate is extremely low 2, 4. Consider blood cultures only if severe systemic features are present (high fever, hypotension, confusion) 2.

Cultures from eye swabs and local abscesses give the highest positive yield if drainage is present 4.

Duration of Treatment and Follow-up

• Mandatory reassessment within 24-48 hours for outpatient cases to prevent progression to vision-threatening orbital cellulitis 1
• Continue IV antibiotics until significant clinical improvement, then transition to oral antibiotics 7
• Total treatment duration: 10-14 days 7
• Daily evaluation of visual function and eye movements during hospitalization 7

Common Pitfalls to Avoid

• Assuming all periorbital infections are preseptal can lead to delayed diagnosis and treatment of orbital cellulitis 2
• Delaying imaging when indicated can prevent early detection of progression to vision-threatening complications 2
• Failing to reassess within 24-48 hours in outpatient cases can miss progression to orbital involvement 1
• Underestimating risk in diabetic patients, who have higher risk for posterior extension and cerebral complications including abscess formation 3