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Pink Eye (Conjunctivitis)

By Marilyn Haddrill; contributions and review by Chris A. Knobbe, MD

A pink eye is the most obvious symptom of conjunctivitis, so the term "pink eye" often is used for this common eye problem that can have many different causes.

A pink eye, along with itching, burning, stinging, irritation, pain, grittiness, crusting or light sensitivity, are all symptoms that provide clues about the type of conjunctivitis you could have.

Contagious forms of pink eye are usually linked to bacterial or viral infections. Non-contagious pink eye can occur when eye irritants such as allergens, dust and smoke are in the environment. Coughing and sneezing can spread contagious pink eye by spraying tiny droplets from infected mucus into the air. Shared towels also can be infected, as well as table tops, counter spaces and bathrooms.

Pink eye can occur in adults, but most often affects young children through epidemics that spread rapidly in classrooms and day care centers. Particularly in these communal settings, you need to take extra precautions to prevent pink eye, such as frequent hand washing by adults and children.

In fact, when pink eye symptoms are present, it's a good idea to keep a can of disinfectant spray handy and use it often.

Because a reddish or pink eye can be a symptom of many different types of eye problems — some that can be quite serious — make sure you consult with your eye doctor.

Why Is the Eye Pink in Pink Eye?

Pink eye results from inflammation of the conjunctiva, the clear membrane covering the white part of the eye (sclera) and interior lining of the eyelids.

Although the conjunctiva is transparent, it contains most of the blood vessels on the eye's surface. So anything that triggers eye inflammation will cause these conjunctival blood vessels to dilate. This contributes to the eye's pink or reddish appearance, particularly evident against the backdrop of the white sclera.

Pink Eye Symptoms and Causes

The way your eyes feel and look will provide some clues about the type of pink eye you have. Besides causing a pink eye, conjunctivitis also can make your eye hurt or itch.

For more common types of pink eye, here are some of the symptoms:

• Allergic conjunctivitis causes itching, redness and excessive tearing in both eyes. Your nose also may be stuffy, itchy and runny.
• Bacterial conjunctivitis often spreads to both eyes and causes a heavy discharge, sometimes greenish. Crusting may appear on eyelids.
• Viral conjunctivitis usually affects only one eye, which has excessive watering and a light discharge. Crusting on eyelids sometimes occurs.

During your eye exam, try to give your doctor exact details of how your eye was affected. You'll be asked questions such as whether the pink eye symptoms came on gradually or suddenly, and if you've been in contact with anyone else who has had pink eye.

Often your answers alone will determine the diagnosis about the type of conjunctivitis you have.

To pinpoint the cause of pink eye and then choose an appropriate treatment, your eye doctor also will examine your eyes and possibly collect a sample (culture) to send out for analysis.

If a sample is needed, the eye will be numbed with drops and the surface will be gently swabbed. Antibiotic eye drops often are prescribed initially. But the medication may be changed, depending on culture results.

If you have a bacterial infection, common causes can include staphylococcus (staph), streptococcus (strep) and — in children — Haemophilus influenza, a flu that is not viral.

Who Gets Pink Eye?

Anyone of any age can have pink eye. But children contract conjunctivitis more often than adults because they have plenty of colds and respiratory tract infections that can be an underlying cause.

Newborn babies also are at significant risk for pink eye. This is because a baby can obtain a bacterial infection causing pink eye while making contact with its mother during the birth process. In fact, according to Ferri's Clinical Advisor 2008, conjunctivitis is found in 1.6 percent to 12 percent of all newborn babies in the United States.

Sometimes, infections in newborn infants are due to common pathogens such as strep or staph. A mother who is infected with a sexually transmitted disease, such as gonorrhea or chlamydia, also can pass along this infection to the baby — which can show up as pink eye.

This is why newly born infants must be evaluated for gonococcal and chlamydial conjunctivitis as well as other forms, so antibiotic treatment can begin immediately, before any eye damage occurs.

As a precaution, most newborn infant eyes are treated with silver nitrate and/or antibiotic ointments, to make sure any possible infections are stopped before they can cause damage. However, this preventive treatment does not work for chlamydial conjunctivitis, which must be treated with antibiotics after a diagnosis.

When exposed to infected secretions, sexually active adults also can have pink eye due to bacteria associated with STDs. If you have a heavy discharge of mucus from your eyes, and other causes of pink eye have been ruled out, be sure and relate any concerns you might have to your doctor.

Contact lens wearers particularly are vulnerable to pink eye, which can be caused by infections from poor hygiene in the handling of lenses, solutions and cases. Also, some soft contact lens wearers can develop an abnormal immune response that can cause giant papillary conjunctivitis (GPC).

Pink eye also can be a symptom of many types of underlying diseases, especially those causing inflammation, including:

• Blepharitis
• Dry eye (keratoconjunctivitis sicca)
• Lyme disease
• Collagen and vascular diseases
• Reiter's syndrome
• Sarcoidosis
• Stevens-Johnson syndrome

In these cases, the disease itself must be treated, to alleviate pink eye and other possible symptoms.

And, of course, anyone who starts sneezing at the first sign of ragweed likely is familiar with allergy symptoms such as a pink eye, eye irritation and itchiness related to non-contagious allergic conjunctivitis.

Can Pink Eye Cause Vision Loss?

Most types of pink eye are not considered serious or threatening to eyesight, especially when appropriate treatment — when necessary — is given in a timely way.

But when other causes have been ruled out, persistent conjunctivitis can signal a potentially serious underlying disease that often only your doctor can diagnose.

Left untreated, certain types of bacterial conjunctivitis can scar the eye's surface. This may lead to permanent eye damage and vision loss.

In extreme and rare cases of uncontrolled conjunctivitis, an eye might even need to be removed because of infection that spreads throughout the eye and its interior (endophthalmitis).

Pink Eye (Conjunctivitis) Treatments

Pink eye treatment options vary, often depending on whether your conjunctivitis is caused by a virus or bacteria. Antibiotic eye ointments or drops may help bacterial forms of conjunctivitis, but don't work for viral forms.

Unless there's some special reason to do so, eye doctors don't normally prescribe medication for viral conjunctivitis, because it usually clears up on its own within a few days to several weeks.

If you have allergic conjunctivitis, artificial tears may help dilute irritating allergens that may be present in your tear film. Antihistamine allergy pills or eye drops also may help control pink eye symptoms.

For all types of conjunctivitis, warm compresses placed on the outside of the eyelids and lubricating eye drops may help eyes feel better.

How To Prevent Pink Eye

Both viral and bacterial conjunctivitis, which can be caused by airborne sources, spread easily to others. So your first line of defense is to avoid the cause of conjunctivitis, such as contaminated hand towels.

Never share washcloths, towels or pillowcases with anyone at home or in a public environment. Don't share eye drops or cosmetics such as eyeliner, eye shadow or mascara. If you have pink eye, replace these items to avoid re-infection after your recovery.

You also want to use common-sense precautions to avoid spreading pink eye from one infected eye to the other. Wash your hands frequently, and avoid touching the corners of your eye or rubbing your eye. If your contaminated hand then touches the unaffected eye, you could end up with pink eye in both eyes.

To avoid allergic conjunctivitis, try these tips:

• Dust and vacuum frequently to eliminate allergens in the home.
• Keep windows and doors closed on days when the airborne pollen count is high.
• Stay in well ventilated areas if you're exposed to smoke, chemicals or fumes.

If you are a swimmer, try using protective swim goggles. Exposure to chlorinated water in pools can be a source of noninfectious pink eye, such as allergic conjunctivitis caused by irritation.

Also, you risk picking up a bacterial eye infection anytime you swim without eye protection in an unsanitary body of water such as the ocean or an underchlorinated swimming pool.

These tips for contact lens wearers also may help prevent pink eye or reduce the chance of re-infection if you have already had conjunctivitis:

• Always follow the strict cleaning and handling instructions taught by your eye care practitioner to avoid bacterial contamination of the contact lens, which could then spread to the eye.
• If you do have pink eye, do not wear your contact lenses until the condition is gone. Otherwise, you run the risk of extending or worsening pink eye symptoms.

• Even if your contact lenses are extended wear and it isn't yet time for disposal, you still may need to replace them, because they could be contaminated.
• Replace any contact lens solutions in which contaminated contact lenses may have been placed.
• When you take a bath or enter a hot tub or any other body of water, be sure to remove contact lenses first to avoid trapping bacteria between your eye and the lens.
• If other explanations have been ruled out, ask your eye doctor about the possibility that you could be having an allergic reaction to your particular contact lens solution or preservatives within that solution.
• Soft contact lens wearers are more susceptible to a form of pink eye known as giant papillary conjunctivitis (GPC), caused by abnormal immune responses. If you have GPC, ask your eye care practitioner about other options, such as wearing a different kind of lens.

Remember, pink eye is a minor eye infection, but sometimes it can develop into a more serious condition.

Because you have no way of knowing for sure what type of pink eye you have, see your eye doctor before using any eye drops in your medicine cabinet from previous infections or eye problems.

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Judith Lee, Gretchyn Bailey, Vance Thompson, MD and Charles Slonim, MD also contributed to this article.

[Page updated April 22, 2010]