Conjunctivitis Explained: What to Know About Pink Eye

Medically Reviewed By Grace Zhang, MD
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Conjunctivitis, or pinkeye, is a type of eye infection. It can have a variety of causes, such as bacteria and viruses. Risk factors for conjunctivitis include poor hygiene and extended contact lens use. Conjunctivitis occurs when the conjunctiva becomes infected or inflamed. This is the thin membrane that lines your eyelid and covers the white part of your eye.

Keep reading to learn more about conjunctivitis, including its causes, types, and how to treat it.

What causes conjunctivitis?

a woman is putting contact lenses in her eye
aire images/Getty Images

Conjunctivitis may be the result of infection with bacteria, fungi, viruses, or other microorganisms.

Pinkeye is a common and highly contagious form of conjunctivitis that is caused by a virus.

Use of extended-wear contact lenses or poor contact lens hygiene can lead to conjunctivitis.

Newborn babies can also develop conjunctivitis from exposure to bacteria in the birth canal.

What are the different types of conjunctivitis?

Conjunctivitis has many different causes, including infections and allergic reactions. It may also result from irritation caused by contact with chemicals, foreign bodies, or even misdirected eyelashes.

Allergic conjunctivitis

Allergies can be a common cause of conjunctivitis. Allergic conjunctivitis may be seasonal, appearing only at certain times of year in response to pollen. It may also 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 allergic conjunctivitis. It can also be caused by abnormalities in the structure of the eyelids. If the eyelid is turned outward, the conjunctiva can be exposed to irritation. If the eyelid is turned inward, the eyelashes can rub on the conjunctiva.

Symptoms of allergic conjunctivitis may:

  • cause itching, tearing, and swelling in the eyes
  • happen alongside allergy symptoms such as an itchy nose, sneezing, sore throat, or asthma
  • affects both eyes at once, though symptoms may be asymmetrical

Viral and bacterial conjunctivitis

Infectious conjunctivitis may be caused by bacteria, fungi, or viruses.

Viral conjunctivitis

Viral conjunctivitis is the most common type of conjunctivitis. It is often called pinkeye.

Viral conjunctivitis is highly contagious. You can get it if a viral respiratory infection such as a cold reaches your eyes, for example, through forceful nose blowing.

Viral conjunctivitis usually begins in one eye and can spread to the other within a few days. It can cause a watery, thin discharge from the eye.

Babies born to people infected with chlamydia or gonorrhea can acquire a serious conjunctival infection during passage through the birth canal. Because of this, most hospitals in the United States require that all newborn babies receive preventive antibiotic eye drops.

Bacterial conjunctivitis

Bacterial conjunctivitis can sometimes occur with an ear infection.

According to the Centers for Disease Control and Prevention (CDC), bacterial conjunctivitis usually causes discharge, or pus. This can cause the eyelids to stick together.

Use of extended-wear contact lenses or improper lens cleaning and storage can also lead to bacterial conjunctivitis.

How do doctors diagnose conjunctivitis?

Doctors do not usually need lab tests to diagnose conjunctivitis. However, they may consider testing if conjunctivitis has lasted longer than 4 weeks or they suspect chlamydia infection in a newborn.

Doctors may perform a PCR test on infected fluid to diagnose conjunctivitis caused by the adenovirus. This test is highly accurate and can produce results within 10 minutes.

To make a general diagnosis of conjunctivitis, a doctor may:

  • look at a history of your symptoms
  • test whether your vision is affected
  • examine your conjunctiva using a bright light

How do doctors treat conjunctivitis?

Your doctor may recommend different treatments for conjunctivitis depending on the type.

Treatment for bacterial conjunctivitis can include antibiotics, eye drops, or ointment applied directly to the eye.

Conjunctivitis caused by allergies can be treated with antihistamines and nonsteroidal anti-inflammatory eye drops. In very severe cases, corticosteroids may be necessary.

There is no known treatment for viral conjunctivitis, although symptoms usually resolve on their own. Some experts believe that people eventually shed the virus through their tears.

Home remedies

You may be able to improve symptoms of conjunctivitis at home. In addition to following a treatment plan outlined by your doctor, try the following self-care measures:

  • Refrain from wearing contact lenses until your conjunctivitis has cleared.
  • Rest your eyes from intense computer work or reading if they feel uncomfortable.
  • Use artificial tears several times daily to wash away allergens.
  • Use cool compresses on your eyes to relieve itching.
  • Use warm, wet compresses on your eyelids to reduce crusting.

What are the risk factors for conjunctivitis?

Several factors can increase your risk of developing conjunctivitis. However, not all people with these risk factors will get conjunctivitis. The risk factors for conjunctivitis include:

  • exposure to allergens such as pollens or animal dander
  • not washing 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:

  • washing your hands before touching your eyes
  • 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

What are the symptoms of conjunctivitis?

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

Common symptoms of conjunctivitis

You may experience all or some of the following conjunctivitis symptoms, including:

  • blurred vision
  • crusting on the eyelids
  • discharge from the eye
  • grittiness
  • itchy eyes
  • increased sensitivity to light
  • increased tear production
  • red, sore eyes (bloodshot eyes)

When should I contact a doctor for conjunctivitis?

Any eye infection can potentially lead to vision problems. Contact your doctor if you have symptoms of conjunctivitis.

Symptoms including blurred vision, sensitivity to light, or double vision following a traumatic injury may indicate 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 following a head injury. These can include blurred vision, double vision, light sensitivity, or discharge from the eyes.

What are the potential complications of conjunctivitis?

With prompt treatment, conjunctivitis usually resolves without complications. You can minimize your risk of serious complications by following the treatment plan you design with your doctor.

Left untreated, conjunctivitis may lead to serious complications, including:

  • corneal scarring
  • loss of vision and blindness
  • meningitis

Other frequently asked questions

Here are some other commonly asked questions about conjunctivitis.

Will conjunctivitis go away on its own?

Viral conjunctivitis will usually go away on its own within 2–3 weeks. However, if symptoms persist or worsen or you suspect bacterial or allergic conjunctivitis, contact your doctor.

What is the fastest way to cure conjunctivitis?

A 2022 review states that cool compresses and artificial tears are fast ways to ease the symptoms of viral conjunctivitis.

Can COVID-19 cause viral conjunctivitis?

COVID-19 may lead to viral conjunctivitis. Any viral infection that can spread to the eyes can cause conjunctivitis. A 2021 review states that conjunctivitis may also be the only symptom of COVID-19 in some people.

How long are you contagious with conjunctivitis?

According to a 2022 review, most cases of viral conjunctivitis are highly contagious for the first 10–14 days. If you have been diagnosed with viral conjunctivitis, you may need to stay away from your workplace for at least 1–2 weeks. This can be especially important if your work puts you in contact with others, such as at a daycare or nursing home.


Conjunctivitis is an infection or inflammation of the conjunctiva. This is the thin membrane lining your eyelid and covering the white of your eye.

The tissues of the conjunctiva are normally protected by your eyelids and tears. They help wash away irritants and contain infection-fighting antibodies.

Sometimes, bacteria, allergens, and other substances may overcome these protective mechanisms and lead to conjunctivitis.

Depending on the cause, conjunctivitis may affect one or both eyes.

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Medical Reviewer: Grace Zhang, MD
Last Review Date: 2022 Oct 28
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