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Alternative names

Inflammation - conjunctiva; Pink eye


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

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.

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 which 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 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 sight. Use of contact lenses, particularly extended-wear lenses, can cause conjunctivitis.

See also:

  • Keratoconjunctivitis sicca
  • Viral conjunctivitis
  • Allergic conjunctivitis
  • Vernal conjunctivitis
  • Trachoma
  • Neonatal conjunctivitis


  • Increased tearing
  • Eye pain
  • Redness in the eyes
  • Gritty feeling in the eyes
  • Itching of the eye
  • Blurred vision
  • Sensitivity to light
  • Crusts that form on the eyelid overnight

Signs and tests

  • Examination of eyes
  • Swab of conjunctiva for analysis


Treatment of conjunctivitis depends upon the cause.

Allergic conjunctivitis may respond to treatment for underlying allergies, or it may disappear on its own when the allergen that caused it is removed. Cool compresses may be soothing for allergic conjunctivitis.

Antibiotic medication, usually eye drops, is effective for bacterial conjunctivitis. Viral conjunctivitis will disappear on its own. The discomfort with viral or bacterial conjunctivitis can be soothed by applying warm compresses (a clean cloth soaked in warm water) to closed eyes.

Expectations (prognosis)

The outcome is usually good with treatment.


Reinfection within a household or school may occur if preventive measures are not followed.

Calling your health care provider

Call for an appointment with your health care provider if symptoms persist longer than 3 or 4 days.


Good hygiene can help prevent the spread of conjunctivitis:
  • Keep hands away from the eye.
  • Wash the hands frequently.
  • Change pillowcases frequently.
  • Replace eye cosmetics regularly.
  • Do not share eye cosmetics.
  • Do not share towels or handkerchiefs.
  • Handle and clean contact lenses properly.

Update Date: 1/19/2004

Raymond S. Douglas, M.D., Ph.D., Department of Ophthalmology, UCLA Medical Center, Los Angeles, CA. Review provided by VeriMed Healthcare Network.

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Last updated: Tue, 06 Jan 2009 00:20:03 GMT