Conjunctivitis

Injury	Disease	Nutrition	Poison

Symptoms	Surgery	Test	Special Topic

Eye

Conjunctivitis

Definition:

Conjunctivitis is inflammation or infection of the membrane lining the eyelids (conjunctiva).

Alternative Names:
Inflammation - conjunctiva; Pink eye
Causes, incidence, and risk factors:

The conjunctiva is exposed to bacteria and other irritants. Tears help protect the conjunctiva by diluting bacteria and washing it away. Tears also contain enzymes and antibodies which kill bacteria.

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There are many causes of conjunctivitis. Viruses are the most common cause. Other causes include bacteria, Chlamydia, fungus, and rarely, parasitic agents.

"Pink eye" refers to a viral infection of the conjunctiva. These infections are especially contagious among children. Handwashing is key to preventing the spread of the virus, which is similar to the type that cause the common cold.

Bacteria are an uncommon cause of conjunctivitis. Many physicians give a mild antibiotic eyedrop for pink eye to prevent bacterial conjunctivitis. Conjunctivitis is also caused by allergies (allergic conjunctivitis), chemical exposure, and certain systemic (throughout the body) diseases.

Newborns can be infected by bacteria in the birth canal. This condition is called ophthalmia neonatorum, and it must be treated immediately to preserve eyesight. Use of contact lenses, particularly extended-wear lenses, can cause conjunctivitis.