Conjunctivitis: A-to-Z Guide from Diagnosis to Treatment to Prevention


Introduction to conjunctivitis:

The conjunctiva is a thin mucus membrane that covers the visible part of the eyeball and the underside of the eyelids. This membrane protects and lubricates the eye.

What is conjunctivitis?

When the conjunctiva becomes inflamed, the condition is called conjunctivitis. In children this is most often a mild infection, but the conjunctiva may become inflamed as a reaction to several different exposures, including bacteria, viruses, allergies, or irritants.

Who gets conjunctivitis?

In newborns it is often caused by bacteria acquired during the process of birth. The eyes of newborns are treated with an antibiotic ointment to prevent this type of potentially serious infection – but the ointment itself can cause a mild, irritant conjunctivitis.

Viral conjunctivitis is common among young children during a variety of viral infections – most often with adenoviruses or enteroviruses. It can accompany a common cold.

Bacterial conjunctivitis is most often caused by staph, strep, H flu, or pneumococcus. It can accompany an ear infection.

Children with allergies can get allergic conjunctivitis when their allergic triggers inflame the conjunctiva.

Smoke, smog, and many irritating products can cause chemical conjunctivitis if they get in the eyes.

The term “pink eye” is sometimes used to describe any of these types of conjunctivitis, but it is most often linked with minor viral and/or bacterial infections of the conjunctiva.

What are the symptoms of conjunctivitis?

The common symptom is redness of the eyes. There may also be eye discomfort or itching. Any type of conjunctivitis may be accompanied by some drainage from the eye, but this is especially true if bacteria are the culprits.

Is conjunctivitis contagious?

Infectious forms can be quite contagious. They can spread in several ways. Here is a typical journey. When one person rubs the eyes, the germs get on the hands. From there, they spread to someone else’s hands (often by way of a fomite). When that person rubs their eyes, transmission is complete. You can imagine how contagious infectious conjunctivitis could be in day cares and other groups of children!

How long does conjunctivitis last?

Most infectious conjunctivitis in children will last for less than a week. Children are usually contagious until they have been treated for at least 24 to 48 hours.

How is conjunctivitis diagnosed?

It is usually diagnosed based on the history and perhaps a physical exam. In the newborn period, or if the conjunctivitis does not act as expected, a further work-up may be warranted.

How is conjunctivitis treated?

Some cases will clear up on their own. Eye drops or ointment are often prescribed. These differ depending on the type of suspected conjunctivitis, but they may relieve symptoms, speed healing, or allow a quicker return to school or day care.

An easy way to instill eye drops is to have the child lie on their back. Place a few drops at the corner of the eyes closest to the nose. Don’t worry about trying to open the eyes first. When the child blinks, the drops will slip into place. Avoiding the drops falling directly onto the eyeball reduces the discomfort and struggle of giving eye drops.

For contact lens wearing children, it is important to insist that they not wear their contact lenses until the eye irritation has completely resolved.

How can conjunctivitis be prevented?

Good hand washing, especially before touching the face, is a key to preventing most cases.

Neonatal conjunctivitis is usually prevented by giving an antibiotic eye ointment soon after birth.

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Dr. Alan Greene

Dr. Greene is the founder of (cited by the AMA as “the pioneer physician Web site”), a practicing pediatrician, father of four, & author of Raising Baby Green & Feeding Baby Green. He appears frequently in the media including such venues as the The New York Times, the TODAY Show, Good Morning America, & the Dr. Oz Show.