What are the diagnostic criteria for preseptal cellulitis?

Preseptal Cellulitis Diagnostic Criteria

Preseptal cellulitis is diagnosed clinically when infection is confined to the eyelids and soft tissues anterior to the orbital septum, presenting with periorbital erythema, edema, warmth, and tenderness without signs of orbital involvement (proptosis, ophthalmoplegia, or vision changes). 1

Clinical Diagnostic Features

Essential Findings

• Periorbital hyperemia and edema (present in 93.1% of cases) 2
• Periorbital swelling (most common presenting complaint in 72.4% of cases) 2
• Warmth and tenderness of the affected eyelid and periorbital tissues 1
• Preserved extraocular motility without pain on eye movement 3
• Normal visual acuity 3
• Absence of proptosis (key distinguishing feature from orbital cellulitis) 1, 4

Distinguishing from Orbital (Postseptal) Cellulitis

The critical distinction is anatomic location relative to the orbital septum. Clinical findings that indicate progression to orbital cellulitis and should prompt immediate escalation include: 1, 4

• Proptosis (only present in orbital cellulitis)
• Ophthalmoplegia or diplopia (only present in orbital cellulitis)
• Pain with extraocular movements (suggests orbital involvement)
• Vision changes (indicates orbital or posterior involvement)
• Older age (mean 7.5 years for orbital vs. 3.9 years for preseptal) 4
• Higher fever rates (82.2% in orbital vs. 51.5% in preseptal) 4
• Markedly elevated CRP (>120 mg/L suggests orbital involvement; median 136.35 mg/L orbital vs. 17.85 mg/L preseptal) 4

Predisposing Factors and Etiology

Common Sources

• Percutaneous introduction of pathogens through skin breaks or trauma 1
• Secondary to sinusitis (52.9% of cases with identifiable predisposing factors) 2
• Odontogenic origin 1

Risk Factors for Progression to Orbital Cellulitis

• High neutrophil count 1
• Absence of infectious conjunctivitis 1
• Gross periorbital edema 1
• Age >3 years 1
• Previous antibiotic therapy 1
• Preexisting sinusitis (present in 77.8% of orbital cellulitis cases) 4

Diagnostic Workup

Clinical Diagnosis

Most cases of preseptal cellulitis are diagnosed clinically without need for imaging or cultures. 1 The diagnosis is made when typical clinical features are present without signs of orbital involvement. 2, 5

Laboratory Testing

• Blood cultures are unnecessary for typical uncomplicated preseptal cellulitis 1
• Consider blood cultures only if severe systemic features present (high fever, hypotension, confusion) 1
• CRP measurement can help differentiate preseptal from orbital cellulitis when clinical examination is equivocal (CRP >120 mg/L suggests orbital involvement) 4

Imaging Indications

Imaging is NOT routinely required for straightforward preseptal cellulitis. 1 However, imaging should be obtained when: 1

• Clinical findings cannot reliably distinguish preseptal from orbital cellulitis
• Any signs of orbital involvement (proptosis, ophthalmoplegia, vision changes)
• Concern for complications (abscess formation, intracranial extension)
• Failure to improve with appropriate antibiotic therapy within 24-48 hours

CT orbits with IV contrast is the imaging modality of choice when imaging is indicated, as it differentiates preseptal from postseptal cellulitis, identifies abscesses, and detects complications like superior ophthalmic vein thrombosis or cavernous sinus thrombosis. 1

MRI of orbits and head with and without contrast is complementary to CT and should be considered when more detailed assessment of intraorbital spread or intracranial complications is needed. 1

Common Pitfalls

• Assuming all periorbital infections are preseptal: Clinical examination alone may not be specific enough to distinguish preseptal from orbital infections, particularly in young children who cannot cooperate with detailed eye examinations. 1
• Delaying imaging when indicated: When clinical findings are equivocal or concerning features are present, prompt imaging prevents progression to vision-threatening complications. 1, 4
• Overlooking sinusitis: Failure to identify and address underlying sinusitis (present in >50% of cases) may lead to treatment failure or recurrence. 2, 4
• Inadequate follow-up: Preseptal cellulitis can progress rapidly to orbital involvement; close monitoring within 24-36 hours is essential to detect early progression. 2, 5