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What is conjunctivitis?

Conjunctivitis is an infection or inflammation of the conjunctiva, the thin membrane that lines the eyelid and also covers the white part of the eye, called the sclera. The delicate tissues of the conjunctiva are protected by the eyelids and the tears, which help wash away irritants and contain infection-fighting antibodies. Sometimes, bacteria, allergens, and other offending substances overcome these protective mechanisms and lead to conjunctivitis. Depending on the cause, conjunctivitis may affect one or both eyes.

Conjunctivitis has many different causes, including infections, allergic reactions, and irritation caused by contact with chemicals, foreign bodies, or even misdirected eyelashes. Infectious conjunctivitis may be caused by bacteria, fungi or viruses. One common, highly contagious form of conjunctivitis, often called pinkeye, is caused by a virus. Use of extended-wear contact lenses or improper lens cleaning and storage can also cause an infection. Babies born to mothers infected with Chlamydia or gonorrhea can acquire a serious conjunctival infection during their passage through the birth canal; thus, most hospitals in the United States require that all newborn babies receive preventive antibiotic eye drops.

Allergies are another common cause of conjunctivitis. Allergic conjunctivitis may be seasonal, appearing only at certain times of year in response to pollen, or it may be perennial, occurring year-round in response to allergens, such as animal dander or feathers. Physical irritants, such as chemicals and foreign bodies in the eye, can cause conjunctivitis. Abnormalities in the structure of the eyelids can also cause conjunctivitis: if the eyelid turns outward, the conjunctiva is exposed to irritation, and if the eyelid turns inward, the eyelashes can rub on the conjunctiva.

Symptoms of conjunctivitis include reddening of the sclera and inside of the eyelids, itchiness, and a gritty feeling. You may have tearing or discharge from your eye, and your eyelids may be crusted when you wake up in the morning. You may have pain and increased sensitivity to light. These symptoms usually resolve with treatment within a few days. Because any eye infection can potentially cause vision problems, contact your health care provider if you have symptoms.

Symptoms of blurred vision, sensitivity to light, or double vision following a traumatic injury can be indicative of a serious condition. Extreme light sensitivity and headache can also be a sign of meningitis, a life-threatening condition. Seek immediate medical care (call 911) for serious symptoms if they follow a head injury, such as blurred vision, double vision, light sensitivity, or discharge from the eyes.

Any eye infection has the potential to affect your vision. Seek prompt medical care for the symptoms of conjunctivitis.


What are the symptoms of conjunctivitis?

Symptoms of conjunctivitis primarily affect the eye and begin within days of the initial infection. They are uncomfortable, but not usually severe or life threatening, and they generally subside within a few days of treatment.

Common symptoms of conjunctivitis

You may experience all of the following conjunctivitis symptoms or just a few including:

Serious symptoms that might indicate a life-threatening condition

In some cases, symptoms of conjunctivitis may occur following eye trauma or may be a sign of meningitis, a potentially life-threatening infection. Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms including:


What causes conjunctivitis?

Conjunctivitis occurs when the conjunctiva, the thin membrane that lines your eyelid and covers the white part of the eye, becomes infected or inflamed. Conjunctivitis may be caused by infection with bacteria, fungi, viruses, or other microorganisms. One common, highly contagious form of conjunctivitis, often called pinkeye, is caused by a virus. Use of extended-wear contact lenses or poor contact lens hygiene can lead to conjunctivitis. Newborn babies can develop conjunctivitis from exposure to bacteria in their mother’s birth canal.

Allergies, which may occur seasonally in response to pollens or year-round in response to other allergens, are a frequent cause of conjunctivitis. Physical irritants, including chemicals, foreign bodies, and misdirected eyelashes, can also cause conjunctivitis.

What are the risk factors for conjunctivitis?

A number of factors increase the risk of developing conjunctivitis. Not all people with risk factors will get conjunctivitis. Risk factors for conjunctivitis include:

  • Exposure to allergens, such as pollens or animal dander
  • Failure to wash your hands before touching your eyes
  • Poor contact lens hygiene
  • Prolonged wearing of contact lenses, especially while sleeping
  • Sharing of makeup or contact lenses with others

Reducing your risk of conjunctivitis

You may be able to lower your risk of conjunctivitis by:

  • Avoiding known allergens
  • Avoiding sharing eye makeup or applicators
  • Avoiding sharing towels or washcloths
  • Cleaning and storing your contact lenses properly
  • Keeping your fingers and hands away from your eyes
  • Removing your contact lenses before going to sleep
  • Replacing eye makeup and applicators frequently

How is conjunctivitis treated?

Treatment of conjunctivitis begins with seeking medical care from your health care provider, who will determine the right approach depending on the type of conjunctivitis you have. Treatment for bacterial conjunctivitis includes antibiotics, eye drops, or ointment applied directly to the eye.

Conjunctivitis caused by allergies is treated with antihistamines, nonsteroidal anti-inflammatory eye drops, and, in very severe cases, corticosteroids. There is no known treatment for viral conjunctivitis, and the symptoms will subside after the disease has run its course.

What you can do to improve your conjunctivitis

In addition to following the treatment plan your health care provider has outlined, you can take self-care measures to improve your conjunctivitis including:

  • Refraining from wearing contact lenses until your conjunctivitis has cleared up

  • Resting your eyes from intense computer work or reading if your eyes are uncomfortable

  • Using artificial tears several times daily to wash away allergens

  • Using cool compresses on your eyes to relieve itching

  • Using warm, wet compresses on your eyelids to reduce crusting

What are the potential complications of conjunctivitis?

With prompt treatment, conjunctivitis resolves without complications. You can help minimize your risk of serious complications by following the treatment plan you and your health care professional design specifically for you. Left untreated, conjunctivitis may lead to serious complications including:

  • Corneal scarring
  • Loss of vision and blindness
  • Recurrent infection
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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2019 Jan 5
  1. Eye burning - itching and discharge. Medline Plus, a service of the National Library of Medicine National Institutes of Health.
  2. Eye problems.
  3. Tierney LM Jr., Saint S, Whooley MA (Eds.) Current Essentials of Medicine (4th ed.). New York: McGraw-Hill, 2011.
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