You may think you're too old to get the eye infection conjunctivitis (pronounced: kun-junk-tih-vy-tus), commonly known as pinkeye. It's usually associated with young kids, probably because it's contagious and tends to sweep through preschools and playgrounds. But even adults get pinkeye.

The good news is that pinkeye is a minor infection and although it might look bad, it's not usually serious.

What Is It?

Conjunctivitis is an inflammation of the conjunctiva, the tissue covering the eye and inner surface of the eyelid. It can be infectious (mainly caused by bacteria or viruses) or noninfectious. The common types of noninfectious conjunctivitis are allergic conjunctivitis (caused by an allergic reaction) and irritant conjunctivitis (caused by anything that irritates the eyes, such as air pollution or chlorine in pools).

When people talk about pinkeye, they're usually referring to the infectious kind, which often is caused by the same bacteria and viruses responsible for colds and other infections, including ear infections, sinus infections, and sore throats.

It's also possible for the same types of bacteria that cause the sexually transmitted diseases (STDs; also called sexually transmitted infections, or STIs) chlamydia and gonorrhea to cause conjunctivitis. If someone touches an infected person's genitals and then rubs his or her own eye or touches a contact lens, the infection can spread to the eye.

In most cases, infectious conjunctivitis causes only minor problems with no risk of damage to the eyes or vision. In very rare instances, though, it can cause permanent damage or even blindness, so be sure to see your doctor if you think you have pinkeye.

What Are the Signs and Symptoms?

The incubation period for conjunctivitis (the length of time between when someone gets infected and when symptoms appear) depends on what's causing it, but usually ranges from a couple of days to a couple of weeks.

Conjunctivitis can affect one or both eyes. The most common symptom is discomfort in the eye, which may feel itchy or gritty. There often will be some discharge from the eyes and pain, swelling of the conjunctiva, and the very pink or red coloring that gives the infection its nickname.

It can be hard to tell whether the infection is caused by a virus or bacteria. In general, the discharge associated with viral conjunctivitis is watery, whereas it will be thicker and more pus-like when the infection is caused by bacteria. When you wake up in the morning, your eyelids may be stuck together (don't be alarmed, though — cleaning your eyes with a warm washcloth will loosen the dried crusts).

Itchiness and tearing are common with allergic conjunctivitis.

How Long Is Conjunctivitis Contagious?

Conjunctivitis that's caused by bacteria is contagious as soon as symptoms appear and remains so as long as there is a discharge from the eye — or until 24 hours after antibiotics are started. Conjunctivitis that's caused by a virus is generally contagious before symptoms appear and can remain so as long as the symptoms last.

Allergic and irritant conjunctivitis are not contagious.

Can I Prevent It?

Because infectious conjunctivitis is highly contagious, wash your hands after interacting with anyone who has the infection. (It's a good idea to wash your hands regularly anyway!) Don't share potentially infected items like washcloths, towels, gauze, or cotton balls. This can be difficult among family members, so just do the best you can.

If you have pinkeye, it's important to wash your hands often, especially after touching your eyes. The infection can easily spread from one eye to the other on contaminated hands or tissues.

It's also wise not to share cosmetics, especially eye makeup. Conjunctivitis-causing bacteria can hang out on beauty products, so avoid using the testers at makeup counters directly on your eyes. And if you've already had a bout of pinkeye, throw away all your eye makeup and splurge on new stuff (but don't start using your new products until the infection is completely gone).

If you wear contact lenses and you've been diagnosed with conjunctivitis, your doctor or eye doctor may recommend that you not wear contact lenses while infected. After the infection is gone, clean your lenses carefully. Be sure to disinfect the lenses and case at least twice before wearing them again. If you wear disposable contact lenses, throw away your current pair and use a new pair.

If you know that you're prone to allergic conjunctivitis, limit allergy triggers in the home by keeping windows and doors closed on days when pollen is heavy and by not letting dust accumulate. Irritant conjunctivitis can only be prevented by avoiding the irritating causes.

Should I See a Doctor?

Because it can be hard to tell which kind of conjunctivitis a person has, it's wise to visit a doctor if your eyes are red and irritated.

How Is It Treated?

Bacterial conjunctivitis is usually treated with prescription antibiotic drops or ointment. Drops — the form of treatment most commonly prescribed for teens — are used up to four times a day. They don't hurt, although they may cause a brief stinging sensation. Even though your eyes should feel and look better after a couple of days, it's important to use the drops for as long as the doctor has prescribed. The infection may come back if you stop too soon.

If a virus is causing conjunctivitis, antibiotic drops will not help. The eye infection will get better as the body fights off the virus.

If you have allergic conjunctivitis, your doctor may prescribe anti-allergy medication in pill or eyedrop form.

What Can I Do to Help Myself Feel Better?

Placing cool or warm packs or washcloths over the infected eye (or eyes) can help. You can also take acetaminophen, if necessary. It may be helpful to clean the infected eye carefully with warm water and fresh, clean gauze or cotton balls.

Keep track of your symptoms, keep your hands clean, visit your doctor as needed, and follow your treatment instructions carefully. Within a week, your eyes should be feeling better.

Reviewed by: Yamini Durani, MD
Date reviewed: May 2012