What Is Conjunctivitis?

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Conjunctivitis, also known as pink eye, is the inflammation or infection of the conjunctiva, the transparent membrane that covers the white part of the eyeball and inner eyelid. Some forms (bacterial, viral) are highly contagious. Others may be triggered by an allergy or exposure to harsh chemicals. Symptoms can be persistent and include redness, itching, tearing, discharge, and more.

Because there are many different causes of conjunctivitis, it is important to see a doctor to determine the appropriate treatment, which may include eye drops, oral medications, ointments, or nothing but comfort measures.

What Is Conjunctivitis (Pink Eye)?
Verywell / Emily Roberts

Conjunctivitis Symptoms

The symptoms of pink eye are triggered when the immune system responds to an infection or irritant with inflammation. This involves the dilation of blood vessels to allow larger immune cells access to the site of an injury. If there is an infection, the accumulation of dead white blood cells and dead bacteria (or viruses) can lead to the formation of pus.

People with conjunctivitis may experience some or all of following symptoms as well as others, depending on the type they have:

  • A pink discoloration of one or both eyes
  • A gritty feeling in the affected eye
  • Itchy or burning eyes 
  • Excessive tearing
  • Swollen eyelids
  • Blurred vision
  • Increased sensitivity to light
  • A discharge from the eye that can form a crust at night


Pink eye is a fairly common condition with many possible causes. They can be broken down into three main types: infectious conjunctivitis, allergic conjunctivitis, and chemical conjunctivitis.

Infectious conjunctivitis: Viruses or bacteria are behind this. The most common viral type, which is highly contagious, is epidemic keratoconjunctivitis (EKC)—what most people are talking about when they refer to pink eye. Bacteria such as Staphylococcus and Streptococcus, usually transmitted by touching your eyes with unclean hands or sharing eye makeup, are often associated with infectious conjunctivitis. A serious type (ophthalmia neonatorum) can also be contracted by babies as they pass through the birth canal.

Allergic conjunctivitis: Any allergy trigger can cause allergic conjunctivitis, including seasonal allergies, food allergies, or contact dermatitis of the eyelids (often caused by the rubbing of eyes). One unique type, called giant papillary conjunctivitis (GPC), is triggered by the ongoing presence of a foreign body in the eye, such as contact lenses.

Chemical conjunctivitis: Also known as toxic conjunctivitis, this can be caused by anything in the environment that irritates or injures the eye, such as smoke, fumes, acid exposure, or over-chlorinated pools.


If you have pink eye, the doctor will want to determine whether the cause is infectious, allergic, or toxic. To do so, he or she will want to assess whether:

  • One or both eyes are involved (as infections usually only affect one eye)
  • There is visible discharge (also indicative of an infection)
  • The discharge is thick or thin (as this can help differentiate a viral or bacterial infection)
  • There is bleeding in the eye (common with viral infections)
  • There are swollen lymph nodes (a clear sign of an infection)
  • There are allergy symptoms (such as hives or allergic rhinitis)

Depending on the type and severity of symptoms, your doctor may want to perform blood tests or cultures to pinpoint an infectious cause, if present. Other tests may include a rapid adenovirus screening to confirm EKC or a fluorescein eye stain to look for abrasions or evidence of a sore or lesion (such as might occur with the herpes simplex virus).


The treatment of pink eye is dependent on the underlying cause. In some cases, the symptoms may resolve on their own. In other cases, they may require topical eye drops or oral medications to treat an underlying infection.

Among the treatment approaches:

  • Bacterial conjunctivitis: Uncomplicated cases can often be treated with antibiotic eye drops or topical ointments. In some cases, an oral antibiotic may be prescribed. Symptoms tend to resolve within three to four days. Most cases ophthalmia neonatorum are avoided today due to the standard practice of applying a topical antibiotic into the eyes of newborns upon delivery.
  • Viral conjunctivitis: As with many viral infections, including the common cold, the illness simply needs to run its course. This can take anywhere from two to three weeks. If there is severe pain or discomfort, steroid eye drops may be used to provide relief. Oral antivirals may be prescribed in certain cases.
  • Allergic conjunctivitis: Removal of the allergy trigger is the best treatment. In the case of giant papillary conjunctivitis, this may involve the removal of your contact lenses for two to three weeks and/or switching from hard lenses to soft ones. Cool compresses, artificial tears, and nonsteroidal anti-inflammatory drugs may help relieve pain and discomfort. Antihistamines and/or topical steroid eye drops may also be prescribed.
  • Chemical conjunctivitis: Treatment involves flushing the eyes with water or a saline wash. Serious cases may require topical steroids. Severe chemical injuries, particularly alkali burns, are considered medical emergencies and are treated in the same way as a burn injury.

A Word From Verywell

If your child has been diagnosed with infectious conjunctivitis, it is important to keep the child away from school until the symptoms have fully resolved. Work to avoid the spread of infection to other members of the family by encouraging regular hand washing, discouraging eye rubbing, and avoiding sharing personal items.

The same preventive steps apply if you are infected. Additionally, if your infection is bacterial, refrain from going back to work until you have had at least 24 hours of treatment with a topical medication. If the cause is viral, you may need to call out or work from home until symptoms fully resolve.

If you return to work early, make every effort not to touch your eye, as this can transfer the discharge to keyboards, doorknobs, and other objects your peers may touch. Avoid wearing an eye patch, as this can promote bacterial growth. Instead, bring antiseptic wipes to sanitize surfaces and avoid shaking hands with colleagues or clients.

Conjunctivitis is usually a minor eye infection, but it can develop into a more serious condition if left untreated. While many forms of pink eye can be treated by a general practitioner or pediatrician, severe cases (or those that fail to respond to therapy) should be seen by an ophthalmologist.

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