Pink eye is one of the most common and treatable eye conditions in children and adults; about 3 million cases of pink eye occur in the United States each year. Treatment is not always needed and the course of treatment depends on the underlying cause.
What is pink eye?
Pink eye, also known as conjunctivitis, involves inflammation of the conjunctiva, the thin, clear tissue that lines the inside of the eyelid and covers the white part of the eye, or sclera. The inflammation makes blood vessels more visible, giving the eye a pink or reddish appearance. The affected eye(s) may be painful, itchy or have a burning sensation. The eyes can also tear or have a discharge that forms a crust during sleep causing the eyes to be “stuck shut” in the morning. Other signs or symptoms that may accompany pink eye include:
- Swelling of the conjunctiva
- Feeling like a foreign body is in the eye(s)
- Sensitivity to bright light
- Enlargement and/or tenderness of the lymph node in front of the ear. This enlargement may feel like a small lump when touched. (Lymph nodes act as filters in the body, collecting and destroying viruses and bacteria.)
- Contact lenses that do not stay in place on the eye and/or feel uncomfortable due to bumps that may form under the eyelid
What causes pink eye?
Pink eye is most often caused by bacterial or viral infections. Allergic reactions or exposure to irritants can also cause pink eye. Pinpointing the cause may be difficult because the signs and symptoms tend to be similar regardless of the underlying cause.
Viral conjunctivitis is caused by a wide variety of viruses, but adenovirus and herpesvirus are the most common viruses that cause pink eye. Viral conjunctivitis may also occur along with an upper respiratory tract infection, cold, or sore throat.
Bacterial conjunctivitis is caused by infection of the eye with bacteria such as Staphylococcus aureus, Streptococcus pneumonia, or Haemophilus. It is a common reason for children to stay home sick from day care or school.
Allergic conjunctivitis can be caused by allergies to pollen, dust mites, molds, or animal dander.
Irritants such as contact lenses and lens solutions, chlorine in a swimming pool, smog or cosmetics may also be an underlying cause of conjunctivitis.
How is pink eye diagnosed?
Conjunctivitis can be diagnosed with an eye examination by a healthcare provider. In some cases, the type of conjunctivitis can be determined by assessing the person’s signs, symptoms, and recent health history (such as whether the person has recently been exposed to someone with conjunctivitis or has a pattern of seasonal allergy). Most cases resolve with time, and there is usually no need for treatment or laboratory tests, unless the person’s history suggests bacterial conjunctivitis.
Viral conjunctivitis is often diagnosed based on a person’s history and symptoms. It tends to occur in both eyes and often accompanies a common cold or respiratory tract infection. Laboratory tests usually are not needed to diagnose viral conjunctivitis; however, testing may be done if a more severe form of viral conjunctivitis is suspected. More severe causes include herpes simplex virus (which usually involves blisters on the skin), varicella-zoster virus (chickenpox and shingles), rubella or rubeola (measles). This testing is performed using a sample of the discharge from an infected eye.
Bacterial conjunctivitis tends to occur in one eye and may accompany an ear infection. A sample of the discharge from the affected eye may be obtained for laboratory tests to determine which type of bacteria is causing the pink eye and how best to treat it.
Allergic conjunctivitis tends to occur in both eyes and often accompanies allergy symptoms, such as an itchy nose, sneezing, and scratchy throat. Allergic conjunctivitis may occur seasonally when pollen counts are high, and it can cause the person’s eyes to itch intensely. A detailed health history may help determine the source of the allergic reaction.
How is pink eye treated?
Most cases of pink eye are mild and will resolve on their own without prescription treatment. In many cases, symptom relief can be achieved by using artificial tears for the dryness and cold packs for the inflammation. (Artificial tears can be purchased without a doctor’s prescription.)
However, you should seek medical attention if you have any of following symptoms:
- Moderate to severe pain in the eye(s)
- Vision problems, such as sensitivity to light or blurred vision, that do not improve when any discharge present is wiped from the eye(s)
- Intense redness in the eye(s)
- Symptoms that become worse or persist when severe viral conjunctivitis is suspected
Also seek medical attention if you have signs of conjunctivitis and you have a weakened immune system from HIV infection, cancer treatment, or other medical conditions or treatments.
Most cases of viral conjunctivitis are mild and will clear up in 7–14 days without treatment and without any long-term consequences. In some cases, however, viral conjunctivitis can take two or more weeks to resolve, especially if complications arise.
Antiviral medication can be prescribed by a physician to treat more serious forms of conjunctivitis, such as those caused by herpes simplex virus or varicella-zoster virus. Antibiotics will not improve viral conjunctivitis as these drugs are not effective against viruses.
Mild bacterial conjunctivitis may get better without antibiotic treatment and without causing any severe complications.
Antibiotics can help shorten the illness and reduce the spread of infection to others. Your healthcare provider may prescribe antibiotic eye drops or ointment, which should resolve the infection within several days.
Consult your healthcare provider if you have been given antibiotics for bacterial conjunctivitis and symptoms have not improved after 24 hours of treatment.
Conjunctivitis caused by an allergy usually improves by eliminating or significantly reducing contact with the allergen (such as pollen or animal dander). Allergy medications and certain eye drops can also provide relief.
Conjunctivitis caused by an irritant often clears up by eliminating the irritant. If you develop conjunctivitis and you wear contacts, stop using them temporarily until the conjunctivitis resolves. In some cases, your healthcare provider may also prescribe drug treatments to improve symptoms.
What steps can I take to prevent pink eye?
Viral and bacterial conjunctivitis are highly contagious and can be easily spread from person to person. Allergic conjunctivitis is not contagious.
If you or someone around you has infectious (viral or bacterial) conjunctivitis, limit its spread by following these steps:
- Wash your hands often with soap and warm water. And wash up immediately if you’ve touched an affected person’s eyes, linens or clothes (for example, when caring for a child who has pink eye). If soap and water are not available, use an alcohol-based hand sanitizer that contains at least 60 percent alcohol.
- Avoid touching or rubbing your eyes.
- If you have conjunctivitis, wash any discharge from around the eyes several times a day.
- Do not use the same eye drop dispenser/bottle for infected and non-infected eyes—even for the same person.
- Avoid sharing articles like towels, blankets, and pillowcases.
- Clean your eyeglasses.
- Clean, store, and replace your contact lenses as instructed by your eye health professional.
- Do not share eye makeup, face makeup, makeup brushes, contact lenses or containers, or eyeglasses.
There are also steps you can take to avoid re-infection once the infection goes away:
- Throw away any eye or face makeup or applicators you used while infected.
- Throw away contact lens solutions you used while infected.
- Throw away contact lenses and cases you used.
- Clean your eyeglasses and cases.
Can newborns get pink eye?
Newborns can develop pink eye, which is called neonatal conjunctivitis, or less commonly, ophthalmia neonatorum. Common symptoms include eye discharge and puffy, red eyelids within one day to two weeks after birth. Newborn conjunctivitis may be caused by infection, irritation, or a blocked tear duct. A mother can pass on infectious conjunctivitis to her newborn during childbirth, even she has no symptoms herself, because she may carry bacteria or viruses in the birth canal. When caused by an infection, neonatal conjunctivitis can be very serious. The most common types of neonatal conjunctivitis include:
- Chlamydial (or inclusion) conjunctivitis is caused by the bacterium Chlamydia trachomatis and can cause swelling of the eyelids with purulent (pus) discharge. Symptoms often appear 5-12 days after birth but may present at any time during the first month of life.
- Gonococcal conjunctivitis is caused by Neisseria gonorrhoeae, the bacterium that causes gonorrhea. Gonococcal conjunctivitis causes pus discharge and swelling of eyelids, which may appear 2-4 days after birth.
- Chemical conjunctivitis can be caused by eye drops or ointment given to newborns to help prevent bacterial eye infections. Symptoms include red eyes and eyelid swelling, and usually resolve in 24-36 hours. Most hospitals are required by state law to put drops or ointment in a newborn’s eyes to prevent disease. The benefits of preventing a more serious type of conjunctivitis are thought to outweigh the risks of chemical conjunctivitis.
- Other bacteria and viruses can also cause conjunctivitis in a newborn. Bacteria that normally live in a woman’s vagina and that are not sexually transmitted can cause neonatal conjunctivitis. The viruses that cause genital and oral herpes can also cause neonatal conjunctivitis and severe eye damage. Such viruses may be passed to the baby during childbirth.
How is pink eye treated in newborns?
Bacterial conjunctivitis may be treated with topical antibiotic eye drops and ointments, oral antibiotics, or intravenous (given through a vein) antibiotics.
A combination of topical and oral, or topical and intravenous treatments are sometimes used at the same time. A saline solution may be prescribed for rinsing the baby’s eye(s) to remove pus, if necessary.
- Chlamydial conjunctivitis in newborns is usually treated with oral antibiotics such as erythromycin. Parents are usually treated as well.
- Gonococcal conjunctivitis in newborns is usually treated with intravenous antibiotics. If untreated, this condition can lead to corneal ulcers and blindness.
- Other types of bacterial and viral conjunctivitis are usually treated with antibiotic eye drops or ointments. A warm compress to the eye may also help relieve swelling and irritation.
- Blocked tear ducts may cause conjunctivitis. If a tear duct is blocked, a gentle warm massage between the eye and nasal area may help. If the blocked tear duct is not cleared by one year of age, surgery may be required.
- Chemical Conjunctivitis usually resolves in 24-36 hours without treatment.
NIH supports a spectrum of research on eye diseases, including studies aimed at developing new treatments for conjunctivitis, as well as basic science studies to better understand the biological factors that contribute to conjunctivitis.
For example, researchers are looking at a layer of diverse microscopic life forms (known as the microbiome) that live on the surface of the eye to see if it plays a role in conjunctivitis and other eye disorders.
Other studies are looking at how certain cell types involved in the immune response might contribute to allergic conjunctivitis.
One study is exploring the unusual properties of the bacterium that cause pneumonia, S. pneumoniae. Although there are effective vaccines for pneumonia, these vaccines don’t prevent the bacterium from causing conjunctivitis. By identifying how the bacterium infects the eye and triggers inflammation in the eye researchers hope to make the existing vaccine effective for preventing eye infections.
The National Eye Institute (NEI) is part of the National Institutes of Health (NIH) and is the Federal government’s lead agency for vision research that leads to sight-saving treatments and plays a key role in reducing visual impairment and blindness.