How do you differentiate and treat bacterial versus viral conjunctivitis?

Differentiating and Treating Bacterial versus Viral Conjunctivitis

Viral conjunctivitis typically presents with watery discharge, follicular reaction on the inferior tarsal conjunctiva, and preauricular lymphadenopathy, while bacterial conjunctivitis shows mucopurulent discharge with matted eyelids upon waking and a papillary rather than follicular reaction—viral cases require only supportive care, whereas moderate to severe bacterial cases benefit from a 5-7 day course of broad-spectrum topical antibiotics. 1

Clinical Differentiation Algorithm

Key Distinguishing Features

Discharge characteristics:

• Viral: Watery, clear discharge with abrupt onset, often starting unilateral but becoming sequentially bilateral within days 1, 2
• Bacterial: Mucopurulent discharge causing eyelids to be matted shut on waking, can be unilateral or bilateral 1, 2

Conjunctival reaction pattern:

• Viral: Follicular reaction on inferior tarsal conjunctiva (small, dome-shaped elevations) 1, 2
• Bacterial: Papillary reaction (flat-topped elevations with central vessels) rather than follicular 1, 2

Associated findings:

• Viral: Preauricular lymphadenopathy (especially with adenovirus), concurrent upper respiratory infection, subconjunctival hemorrhages, chemosis, and eyelid swelling 1
• Bacterial: Less common preauricular lymphadenopathy unless hypervirulent organisms involved, may have concurrent otitis media, sinusitis, or pharyngitis in children 1

Critical Red Flags Requiring Immediate Ophthalmology Referral

The following warrant urgent specialist evaluation 1, 2:

• Visual loss or decreased vision
• Moderate to severe pain
• Severe purulent discharge (consider gonococcal infection)
• Corneal involvement on fluorescein staining
• Vesicular rash on eyelids or nose (suggests herpes simplex)
• History of herpes simplex virus eye disease
• Immunocompromised state
• Recent ocular surgery
• Lack of response to therapy after 5-7 days

Treatment Approach

Viral Conjunctivitis Management

The American Academy of Ophthalmology recommends avoiding antibiotics entirely for viral conjunctivitis, as they provide no benefit and may cause toxicity. 2

Supportive care measures:

• Artificial tears for symptomatic relief 1
• Cold compresses 3
• Topical antihistamines for symptomatic relief if needed 1
• Self-limited course, typically resolving within 5-14 days 1

Patient education is paramount:

• Highly contagious for 10-14 days from symptom onset 1
• Strict hand hygiene with soap and water 1
• Avoid sharing towels, pillows, or personal items 1
• Consider work/school restrictions during peak contagious period 1

Follow-up timing:

• Patients with severe viral conjunctivitis should be re-evaluated within 1 week 1
• Return if symptoms persist beyond 2-3 weeks 1

Special consideration for severe cases:

• Topical corticosteroids may be considered with extreme caution and close ophthalmology follow-up for severe cases with pseudomembranes or subepithelial infiltrates 1
• Regular IOP monitoring required if corticosteroids used 1

Bacterial Conjunctivitis Management

Mild bacterial conjunctivitis is usually self-limited and may resolve without specific treatment, but topical antibiotics may decrease the duration of infection. 1

For moderate to severe bacterial conjunctivitis, a 5-7 day course of broad-spectrum topical antibiotic is usually effective. 1

Antibiotic selection:

• No evidence demonstrates superiority of any particular topical antibiotic agent 1
• Common options include erythromycin ophthalmic ointment (approximately 1 cm applied up to six times daily) 4
• Bacitracin for susceptible organisms 5
• Fluoroquinolones, chloramphenicol, or other broad-spectrum agents based on local resistance patterns 6

Special bacterial considerations requiring systemic treatment:

• Gonococcal conjunctivitis: Marked eyelid edema, severe hyperpurulent discharge, risk of corneal perforation—requires urgent systemic therapy 1, 2
• Chlamydial conjunctivitis: Requires systemic treatment and evaluation of sexual partners 1, 2
• Neonatal conjunctivitis: Requires prompt evaluation and may need hospitalization for parenteral therapy 1

Common Pitfalls to Avoid

Indiscriminate antibiotic use:

• Viral conjunctivitis will not respond to antibacterial agents 1
• Unnecessary antibiotics lead to toxicity, resistance, and delayed diagnosis 1, 2

Corticosteroid misuse:

• Never use topical corticosteroids without confirming non-herpetic etiology 7
• Can cause devastating complications in herpes simplex keratitis 7

Missed serious diagnoses:

• Chronic or recalcitrant conjunctivitis may indicate underlying malignancy (sebaceous or squamous cell carcinoma) 1, 2
• Failing to recognize dry eye and blepharitis as the most frequent causes of conjunctival inflammation leads to inadequate treatment 2

Inadequate patient education:

• Failing to emphasize contagiousness leads to community spread 1
• Patients must understand strict hand hygiene and avoidance of shared items 1