Conjunctivitis is swelling (inflammation) or infection of the membrane lining the eyelids (conjunctiva).
Inflammation - conjunctiva; Pink eye
The conjunctiva is exposed to bacteria and other irritants. Tears help protect the conjunctiva by washing away bacteria. Tears also contain enzymes and antibodies that kill bacteria.
There are many causes of conjunctivitis. Viruses are the most common cause. Other causes include:
"Pink eye" refers to a viral infection of the conjunctiva. These infections are especially contagious among children.
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.
Treatment of conjunctivitis depends on the cause.
Allergic conjunctivitis may respond to allergy treatment. It may disappear on its own when the allergen that caused it is removed. Cool compresses may help soothe allergic conjunctivitis.
Antibiotic medication, usually eye drops, is effective for bacterial conjunctivitis. Viral conjunctivitis will disappear on its own. Many doctors give a mild antibiotic eyedrop for pink eye to prevent bacterial conjunctivitis.
You can soothe the discomfort of viral or bacterial conjunctivitis by applying warm compresses (clean cloths soaked in warm water) to your closed eyes.
The outcome is usually good with treatment.
Reinfection within a household or school may occur if you don't follow preventive measures.
Call for an appointment with your health care provider if your symptoms last longer than 3 or 4 days.
Good hygiene can help prevent the spread of conjunctivitis:
Wright JL, Wightman JM. Red and painful eye. In: Marx JA, ed. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, Pa: Mosby Elsevier; 2009:chap 32.
Rubenstein JB, Virasch V. Conjunctivitis: Infectious and noninfectious. In: Yanoff M, Duker JS, eds. Ophthalmology. 3rd ed. St. Louis, Mo: Mosby Elsevier; 2008:chap 4.6.