What is the most common cause of infectious conjunctivitis?

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

Answer: (D)

Viral conjunctivitis is the most common infectious cause, typically due to adenovirus, and it spreads easily from person to person through hand contact and contaminated surfaces. It often presents with watery discharge, redness, a gritty sensation, and can involve both eyes while sometimes accompanying a mild upper respiratory infection. The illness is usually self-limited and mainly managed with supportive care and good hygiene to prevent spread.

Gonococcal conjunctivitis is much less common and tends to present with a hyperacute, copious purulent discharge and can threaten the cornea, requiring urgent systemic antibiotics. Allergic conjunctivitis is not infectious at all; it’s an IgE-mediated reaction characterized by itching, tearing, and redness, often bilaterally and associated with a history of allergies. Bacterial conjunctivitis does occur and can cause purulent discharge and eyelid crusting, but overall it is less common than viral conjunctivitis in the general population.