What is the diagnosis for photophobia and periorbital swelling?

Photophobia and Periorbital Swelling: Differential Diagnosis

The combination of photophobia and periorbital swelling most commonly indicates orbital or periorbital cellulitis (especially when associated with sinusitis), but also requires consideration of bacterial keratitis, viral conjunctivitis, and intracranial complications of sinusitis. 1, 2

Primary Diagnostic Considerations

Orbital vs. Periorbital (Preseptal) Cellulitis

This is the most critical distinction to make immediately, as orbital cellulitis requires hospitalization while periorbital cellulitis may be managed outpatient. 2

Key differentiating features for orbital cellulitis include:

• Proptosis (forward displacement of the eye) 2, 3
• Impaired or painful extraocular movements 2, 4
• Ophthalmoplegia 2, 4
• Decreased visual acuity 2

Periorbital (preseptal) cellulitis presents with:

• Eyelid swelling without proptosis 3, 5
• Normal extraocular movements 5
• Normal visual acuity 5
• Infection limited to tissues anterior to the orbital septum 6

Clinical context matters significantly:

• Periorbital cellulitis occurs more frequently (83% of cases) and predominantly affects children under 5 years 3
• Orbital cellulitis is less common (17% of cases) but more frequently affects children over 5 years 3
• Sinusitis (especially ethmoid) is the predisposing factor in 79% of orbital cellulitis cases 3
• Upper respiratory infection (68%) and eyelid trauma (20%) are the most common predisposing factors for periorbital cellulitis 3

Bacterial Keratitis

Photophobia combined with periorbital inflammation should prompt examination for corneal involvement. 1

Characteristic features include:

• Pain, redness, and blurred vision 1
• Corneal infiltrates or ulcerations on examination 1
• Discharge 1
• Anterior chamber inflammation 1

Risk factors that increase suspicion:

• Contact lens wear 1
• Corneal trauma 1
• Recent corneal surgery 1
• Ocular surface disease 1

Intracranial Complications of Sinusitis

Severe headache with photophobia and periorbital swelling suggests potential intracranial extension. 1

Warning signs include:

• Severe headache 1
• Seizures 1
• Focal neurologic findings 1
• Altered mental status 1

Possible complications:

• Epidural abscess 1
• Subdural empyema 1
• Cerebritis or brain abscess 1
• Meningitis 1
• Cavernous sinus thrombosis 1

Viral Conjunctivitis

Several viral infections present with photophobia and periorbital swelling, though typically less severe than bacterial orbital infections. 1

Measles (rubeola) specifically presents with:

• Bilateral conjunctivitis with photophobia 1
• Fever and maculopapular rash 1
• Cough and coryza 1
• Keratitis develops before rash appearance 1

Epstein-Barr virus can cause:

• Follicular conjunctivitis (typically unilateral) 1
• Periorbital edema 1
• Subconjunctival hemorrhage 1
• Associated systemic symptoms (fever, pharyngitis, lymphadenopathy) 1

Diagnostic Imaging Algorithm

For suspected orbital cellulitis or complications:

• CT orbits with IV contrast is the initial imaging of choice 1, 2
• Differentiates preseptal from postseptal cellulitis and identifies abscesses 1
• Detects superior ophthalmic vein or cavernous sinus thrombosis 1

For suspected intracranial complications:

• MRI brain with contrast provides superior soft-tissue resolution 1
• More sensitive for early cerebritis, meningitis, and cavernous sinus thrombosis than CT 1
• Consider adding MRA/MRV if vascular complications suspected 1

Imaging is NOT indicated for:

• Uncomplicated acute rhinosinusitis without orbital signs 1
• Clear preseptal cellulitis without concerning features 1

Critical Pitfalls to Avoid

Do not delay CT imaging when proptosis, visual changes, or ophthalmoplegia are present - this can lead to missed orbital cellulitis requiring urgent intervention. 2

Do not rely solely on obvious clinical signs - 50.5% of patients with orbital abscess did not have proptosis, pain with eye movement, or ophthalmoplegia. 4 Additional high-risk features include neutrophil count >10,000/μL, absence of infectious conjunctivitis, gross periorbital edema, age >3 years, and previous antibiotic therapy. 4

Do not overlook fungal causes in diabetic or immunocompromised patients - invasive fungal infections (Aspergillus, mucormycosis) require urgent evaluation due to high morbidity and mortality. 1, 7

Do not patch eyes in contact lens wearers with corneal abrasions - this increases the risk of bacterial keratitis. 1

Do not assume imaging abnormalities confirm bacterial sinusitis - the majority of children with uncomplicated URI show significant sinus abnormalities on imaging that do not represent bacterial infection. 1