Encyclopedia - Conjunctivitis

What causes conjunctivitis?
How is it treated?

More commonly known as "pink eye", conjunctivitis is an eye infection that can be highly contagious. It causes the conjunctiva, the thin transparent layer covering the inner eyelid and the white part of the eye, to become inflamed, irritated and red. (See Anatomy of the Eye.)

What causes conjunctivitis?

Conjunctivitis occurs most commonly in children, though it can occur at any age. There are generally four types of conjunctivitis:

• viral -- which accompanies a cold or other viral infection
• bacterial -- such as from strep, staph or other bacterial infections
• allergic -- an allergy to dust, molds, pets, cosmetics and other potential irritants
• ophthalmia neonatorum -- a form of conjunctivitis found only in newborns

Other possible causes of conjunctivitis include a partially blocked tear duct, unsanitary environments, and working with intense light.

Symptoms of conjunctivitis may be nothing more than a minor irritant to some people. Others, however, may notice several other, more painful, symptoms including itching, swelling, crusty eyelids after sleeping, a discharge from the eye, excessive watering, light sensitivity, and excessive redness.

How is it treated?

Most often, conjunctivitis disappears on its own with self-care and typically improves within one week. Because conjunctivitis spreads easily from eye to eye and person to person, it is important to exercise good hygiene during an episode of conjunctivitis. People with conjunctivitis should wash their hands frequently, avoid touching their eyes, refrain from wearing makeup, and not share towels, linens or other items in contact with the infected eye. To ease discomfort, warm-water compresses may be used, taking care to discard or launder the compress after use.

If symptoms do not resolve and the eye is left untreated, conjunctivitis can damage the cornea and affect vision permanently. Seek immediate medical attention if the conjunctivitis does not disappear or the following more severe symptoms occur:

• the symptoms begin to affect vision
• pain increases
• rapid recurrence
• discharge becomes greenish or yellowish

Usually, eye care professionals can test the discharge with a simple culture and establish the exact cause of conjunctivitis. In some cases, doctors may prescribe antiviral, antibiotic eye drops or ointments to control the infection. In cases of allergic conjunctivitis, removing the source of allergy may solve the problem, or antihistamine eye drops or steroid-based medications may be prescribed if removal of the allergen is not possible. Newborns are routinely treated with antibiotic eye drops or ointment.