What are the key clinical features that differentiate viral conjunctivitis from bacterial conjunctivitis in a primary care setting?

In a primary care setting, the differentiation between viral and bacterial conjunctivitis, based on the provided guidelines, primarily involves their typical resolution times and the appropriateness of antibiotic treatment.

• Resolution Time: Acute viral (non-herpetic) conjunctivitis usually resolves within one to two weeks without antimicrobial treatment NICE CKS. In contrast, acute bacterial conjunctivitis typically resolves within 5–7 days without treatment NICE CKS.
• Antibiotic Use: Topical antibiotics are generally not appropriate for viral conjunctivitis and may cause adverse reactions NICE CKS. For bacterial conjunctivitis, while often self-limiting, topical antibiotics may be considered if the condition is severe, if rapid resolution is required, or as a delayed treatment strategy if symptoms have not resolved within 3 days NICE CKS.
• Contagiousness Duration: Individuals with viral conjunctivitis may be infectious for up to 14 days from the onset of symptoms NICE CKS.