Differential Diagnosis of Photophobia and Periorbital Swelling

Primary Diagnostic Considerations

The American College of Radiology suggests that the combination of photophobia and periorbital swelling most commonly indicates orbital or periorbital cellulitis, especially when associated with sinusitis, and also requires consideration of bacterial keratitis, viral conjunctivitis, and intracranial complications of sinusitis 1, 2
The American Academy of Ophthalmology recommends examining for corneal involvement when photophobia is combined with periorbital inflammation, characteristic features include pain, redness, blurred vision, corneal infiltrates or ulcerations, discharge, and anterior chamber inflammation 3, 4
The American College of Radiology states that severe headache with photophobia and periorbital swelling suggests potential intracranial extension, warning signs include severe headache, seizures, focal neurologic findings, and altered mental status 1

The American College of Radiology recommends CT orbits with IV contrast as the initial imaging of choice for suspected orbital cellulitis or complications, which differentiates preseptal from postseptal cellulitis and identifies abscesses 5, 2
The American College of Radiology suggests that MRI brain with contrast provides superior soft-tissue resolution for suspected intracranial complications, and is more sensitive for early cerebritis, meningitis, and cavernous sinus thrombosis than CT 6, 1

The American College of Radiology advises against delaying CT imaging when proptosis, visual changes, or ophthalmoplegia are present, as this can lead to missed orbital cellulitis requiring urgent intervention 2
The American Academy of Ophthalmology recommends against patching eyes in contact lens wearers with corneal abrasions, as this increases the risk of bacterial keratitis 3, 4
The American College of Radiology warns against overlooking fungal causes in diabetic or immunocompromised patients, as invasive fungal infections require urgent evaluation due to high morbidity and mortality 6, 7

The American Academy of Ophthalmology recommends considering alternative diagnoses such as uveitis, which presents with eye pain, photophobia, blurred vision, and headache, but typically lacks periorbital swelling and fever, and requires urgent ophthalmology referral and slit-lamp examination 8
The American College of Radiology suggests that a relative afferent pupillary defect is a red flag indicating orbital cellulitis, which mandates urgent CT imaging 8

The American College of Radiology recommends identifying orbital or subperiosteal abscesses requiring surgical drainage using CT orbits with IV contrast 9
The Infectious Diseases Society of America suggests that empiric antibiotic regimens such as IV ceftriaxone plus clindamycin, or alternative vancomycin plus ceftriaxone if MRSA prevalence is high, are effective against common pathogens 8

The American College of Radiology recommends urgent evaluation for invasive fungal sinusitis in immunocompromised patients, which has a mortality rate of 50-80% and requires systemic antifungal therapy plus surgical debridement 9