What Is Conjunctivitis? - Causes, Symptoms & Treatment

Instructor: Danielle Haak

Danielle has a PhD in Natural Resource Sciences and a MSc in Biological Sciences

I bet you've had conjunctivitis before! Most kids have experienced this disease at one point in time. It's more commonly known as 'pink eye.' Read this lesson to learn its causes, review its symptoms, and find out how to treat it!

What Is Conjunctivitis?

You've probably had conjunctivitis and just didn't know it! It's commonly referred to as 'pink eye' because the symptoms cause the whites of your eyes to turn pink. Your eye is covered by a transparent membrane, called the conjunctiva, and conjunctivitis is the infection or inflammation of this membrane. The tiny blood vessels that feed this membrane become enlarged when they are infected and become more visible. This is what causes the whites of your eyes to appear pink. Conjunctivitis can be highly contagious, and it's commonly found in children (particularly bacterial conjunctivitis).

What Causes Conjunctivitis?

Conjunctivitis is caused by a number of different eye infections. It can include a viral or bacterial infection, allergies, a foreign substance in the eye, or a blocked tear duct (in newborns). The most common form of conjunctivitis is caused by a virus, specifically an adenovirus, which commonly causes problems in the upper respiratory system.

Symptoms of Conjunctivitis

Symptoms vary slightly based on the cause. With viral conjunctivitis, the infection may affect one or both eyes and will usually result in a watery discharge. Bacterial conjunctivitis, in contrast, produces a thicker, yellowish-green discharge and may include mild pain and slight swelling of the eyelid. Both types are contagious.

Conjunctivitis caused by allergies affects both eyes and results in itching, tearing, redness, and swelling of the eyes. Conjunctivitis caused by a foreign object or substance in the eye results in a clear, watery discharge but usually clears up on its own in about a day.

Also called pink eye, conjunctivitis results in the whites of the eyes turning pink.
Conjunctivitis image

Treatment Options

None of these symptoms sound very fun, so how is conjunctivitis treated? Again, it depends on what type of conjunctivitis is wreaking havoc on the eye. Bacterial conjunctivitis is usually treated with an antibacterial eye drop or eye ointment, which is thicker than a drop. Typically the antibacterial treatment will vanquish the infection within two to four days.

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