What are the differences in presentation between viral and bacterial conjunctivitis?

Differences in Presentation Between Viral and Bacterial Conjunctivitis

Viral and bacterial conjunctivitis have distinct clinical presentations that help guide diagnosis and management, with viral conjunctivitis typically presenting with watery discharge and bilateral involvement, while bacterial conjunctivitis commonly presents with purulent discharge and matted eyelids.

Key Distinguishing Features

Viral Conjunctivitis

• Onset and Pattern: Abrupt onset, often unilateral initially but frequently becomes sequentially bilateral 1
• Discharge: Primarily watery discharge 2
• Conjunctival Reaction: Follicular reaction of inferior tarsal conjunctiva 1
• Associated Findings:
  • Often accompanied by concurrent upper respiratory infection 1
  • Preauricular lymphadenopathy may be present, especially with adenoviral infections 1
  • Chemosis, eyelid swelling, and erythema can be present and may even resemble orbital cellulitis in severe cases 1, 3
• Duration: Self-limited, typically resolving within 5-14 days 1
• Complications: Severe cases may develop pseudomembranes, subepithelial corneal infiltrates, conjunctival scarring, and in rare cases, lacrimal stenosis 1

Bacterial Conjunctivitis

• Onset and Pattern: Can be unilateral or bilateral 1
• Discharge: Purulent or mucopurulent discharge 1, 2
• Eyelid Presentation: Mattering and adherence of eyelids upon waking is highly suggestive of bacterial etiology 4, 2
• Conjunctival Reaction: Papillary rather than follicular reaction 1
• Associated Findings:
  • May be associated with concurrent bacterial otitis media, sinusitis, or pharyngitis, particularly in children 1
  • Preauricular lymphadenopathy is less common than in viral conjunctivitis unless caused by hypervirulent organisms 1
• Duration: Uncomplicated cases typically resolve in 1-2 weeks, often faster with antibiotic treatment 4
• Complications: Corneal infection is a potential complication, particularly with virulent organisms like gonococcus 1

Population Differences

• Age Distribution:
  • Bacterial conjunctivitis is more common in children 2
  • Viral conjunctivitis is more common in adults 2
• Risk Factors:
  • Viral: Exposure to infected individuals (especially in school settings), recent ocular testing 1
  • Bacterial in children: Contact with infected individuals, concomitant bacterial otitis media or pharyngitis 1
  • Bacterial in adults: Contact with infected individuals, oculogenital spread, unhygienic living conditions, lid malposition, severe tear deficiency, immunosuppression 1

Special Considerations

Gonococcal Conjunctivitis

• Presentation: Marked eyelid edema, marked bulbar conjunctival injection, marked purulent discharge, preauricular lymphadenopathy 1
• Important Sign: Corneal infiltrate or ulcer (often begins superiorly) that may lead to corneal perforation 1
• Progression: Rapid development of severe hyperpurulent conjunctivitis in adults 1
• Complications: Corneal infection, scarring, perforation, systemic spread (septicemia, arthritis) 1

Herpes Simplex Virus Conjunctivitis

• Laterality: Usually unilateral, though can be bilateral in atopic, pediatric, or immunocompromised patients 1
• Distinctive Signs: Vesicular rash or ulceration of eyelids, dendritic epithelial keratitis of cornea 1
• Duration: Usually subsides without treatment within 4-7 days unless complications occur 1

Diagnostic Pitfalls

• No single sign or symptom accurately differentiates viral from bacterial conjunctivitis with complete certainty 2
• Severe viral conjunctivitis (particularly adenoviral) can present with marked eyelid swelling resembling preseptal cellulitis 3
• Mattering and adherence of eyelids on waking, lack of itching, and absence of history of conjunctivitis are the strongest factors associated with bacterial conjunctivitis 4

Management Implications

• Viral conjunctivitis is typically self-limiting and requires only supportive care 4, 2
• Bacterial conjunctivitis may benefit from topical antibiotics to decrease duration and allow earlier return to work or school 4
• Indiscriminate use of topical antibiotics should be avoided as viral conjunctivitis will not respond to antibacterial agents 1
• Conjunctivitis caused by sexually transmitted infections (gonorrhea, chlamydia) requires systemic treatment in addition to topical therapy 4