When the white part of your eye turns reddish or pink and becomes itchy, you may have a condition called pink eye. Pink eye is also known as conjunctivitis. Pink eye can be caused by a bacterial or viral infection, or it may be caused by an allergic reaction.

Bacterial and viral conjunctivitis are both highly contagious, and you may be contagious for up to two weeks after symptoms first appear. Allergic conjunctivitis is not contagious.

Most cases of pink eye are viral or bacterial, and can occur with other infections.

A pink eye infection can be passed to someone else in the same ways other viral and bacterial infections can be spread. The incubation period (the time between becoming infected and symptoms appearing) for viral or bacterial conjunctivitis is about 24 to 72 hours.

If you touch something with the virus or bacteria on it, and then touch your eyes, you can develop pink eye. Most bacteria can survive on a surface for up to eight hours, though some can live for a few days. Most viruses can survive for a couple days, with some lasting for two months on a surface.

The infection can also be spread to others through close contact, such as a handshake, hug, or kiss. Coughing and sneezing can also spread the infection.

You’re at increased risk for pink eye if you wear contact lenses, especially if they’re extended-wear lenses. That’s because bacteria can live and grow on the lenses.

Pink eye is contagious once symptoms appear, and the condition remains contagious as long as there is tearing and discharge. If your child has pink eye, it’s best to keep them home from school or daycare until symptoms disappear. Most cases are mild, with symptoms often clearing up within a few days.

If you have pink eye, you can return to work any time, but you will need to take precautions, such as washing your hands thoroughly after touching your eyes.

Pink eye isn’t any more contagious than other common infections, such as a cold, but it does require effort to keep from spreading it or picking it up from someone else.

The first sign of pink eye is a change in color of the white part of your eye, called the sclera. It’s the tough outer layer that protects the iris and the rest of the eye.

Covering the sclera is the conjunctiva, a thin, transparent membrane that becomes inflamed when you get pink eye. The reason your eye looks red or pink is because the blood vessels in the conjunctiva become inflamed, making them more visible.

Inflammation or irritation of the conjunctiva doesn’t always mean pink eye. In infants, a closed tear duct can irritate the eye. Swimming in a pool with a lot of chlorine can redden your eyes, too.

Actual conjunctivitis tends to have other symptoms, including:

  • itchiness
  • gooey discharge that may form crust around your eyelids while you sleep
  • a feeling like there is dirt or something irritating your eye
  • watery eyes
  • sensitivity to bright lights

Pink eye can form in one or both eyes. If you wear contact lenses, they may feel very uncomfortable, like they don’t fit the way they normally do. If possible, you should avoid wearing your contacts while you have symptoms.

In serious cases, conjunctivitis can cause some swelling in the lymph node near your ear. It may feel like a small lump. The lymph nodes help the body fight infections. Once the viral or bacterial infection is cleared up, the lymph node should shrink.

See a doctor if you notice conjunctivitis symptoms in your eyes or those of your child. An early diagnosis can help reduce symptoms and lower the odds of spreading the infection to other people.

If your symptoms are mild and there are no signs of other health problems, such as a respiratory infection, earache, sore throat, or fever, you may be able to wait a day or two before seeing a doctor. If your symptoms subside, your symptoms may be caused by an irritation to the eye as opposed to an infection.

If your child develops pink eye symptoms, take them to a pediatrician promptly instead of waiting for symptoms to improve on their own.

During the appointment, your doctor will do a physical examination of the eyes and review your symptoms, as well as your medical history.

Bacterial pink eye tends to occur in one eye and may coincide with an ear infection. Viral pink eye usually appears in both eyes, and may develop along with a cold or respiratory infection.

Only in rare cases are tests needed to confirm a diagnosis of pink eye.

Mild cases of pink eye don’t always require treatment. You may use artificial tears to help with dry eyes and cold packs to relieve the discomfort of eye inflammation.

Viral conjunctivitis may not require treatment, though if the condition was caused by the herpes simplex virus or the varicella-zoster virus (shingles), anti-viral medications may be prescribed.

Bacterial pink eye may be treated with antibiotic eye drops or ointments. Antibiotics can help reduce the time you experience symptoms and cut down the time during which you are contagious to others. Antibiotics aren’t effective in treating a virus.

In general, you shouldn’t touch your eyes with your hands, especially if you haven’t washed your hands recently. Protecting your eyes in this way should help prevent pink eye.

Other ways to help prevent pink eye include:

  • using clean towels and washcloths daily
  • avoiding sharing towels and washcloths
  • changing pillowcases frequently
  • not sharing eye cosmetics

Viral and bacterial pink eye are both contagious while symptoms are present. Allergic conjunctivitis is not contagious.

By taking preventive steps and keeping your child home as much as possible while symptoms are present, you can help reduce the risk of spreading the infection.