What is a classic sign of acute bacterial conjunctivitis?

• A. Conjunctival injection with purulent discharge
• B. Watery discharge with injection
• C. Eye pain with photophobia
• D. Itchy eyelids

Answer: (A)

Purulent discharge with conjunctival injection is the classic sign of acute bacterial conjunctivitis. The discharge is typically thick, opaque, and may crust the eyelids, especially in the morning, reflecting pus produced by bacterial infection. The redness comes from inflamed conjunctival vessels. This combination helps distinguish it from viral conjunctivitis, which usually has a watery discharge and may accompany upper respiratory symptoms, and from allergic conjunctivitis, where itching is prominent and the discharge is often watery or mucus-like. Eye pain and photophobia are more suggestive of corneal involvement rather than simple conjunctival infection, so they’re not typical of straightforward acute bacterial conjunctivitis.