An adult presents with a red eye, watery discharge, and a palpable preauricular node. What is the most likely diagnosis?

• A. Bacterial Conjunctivitis
• B. Viral Conjunctivitis
• C. Allergic Conjunctivitis
• D. Gonococcal Conjunctivitis

Answer: (B)

The main idea here is using the eye discharge and accompanying findings to distinguish types of conjunctivitis. Viral conjunctivitis typically presents with a red eye and watery discharge, often with swelling of the preauricular lymph nodes due to drainage from the infected conjunctiva. This pattern fits adenoviral infections, which are common and highly contagious.

Bacterial conjunctivitis usually shows a more thick, purulent or mucopurulent discharge with crusting around the lashes, and preauricular lymphadenopathy is less prominent. Allergic conjunctivitis tends to cause itching, a stringy or watery/mucoid discharge, and is often bilateral with conjunctival itching and cobblestone papillae, not typically associated with a preauricular node. Gonococcal conjunctivitis presents with a profuse, copious purulent discharge and can cause rapid corneal involvement; its presentation is more severe and not simply watery discharge.

So the combination of a red eye with watery discharge and a palpable preauricular lymph node is most characteristic of viral conjunctivitis.