Definition: Conjunctivitis, commonly known as pink eye, is an inflammation or infection of the conjunctiva, the clear membrane covering the white part of the eye and lining the inner surface of the eyelids.

Causes: Pink eye can be caused by viruses, bacteria, allergens, or irritants. Viral and bacterial conjunctivitis are highly contagious, while allergic and irritant conjunctivitis are not infectious.

Treatment: Treatment depends on the cause of conjunctivitis. Viral conjunctivitis often resolves on its own, while bacterial conjunctivitis may require antibiotic eye drops or ointment. Allergic conjunctivitis can be managed with antihistamine eye drops or oral medications, and irritant conjunctivitis usually improves by avoiding the irritant and using lubricating eye drops to soothe the eyes.