Pink Eye (Conjunctivitis): Causes, Symptoms & Treatment
A boy shows signs of pink eye. Conjunctivitis is a leading cause of children being absent from day care or school.
Credit: Aisylu Ahmadieva | Shutterstock

Pink eye, also known as conjunctivitis, develops when the blood vessels in the transparent membrane, or conjunctiva, that line the eyelid and the white part of the eyeball get inflamed. The inflamed membranes' veins swell and gives the whites of the eyes a distinct pink or red tint, which is where it gets its name.

Pink eye is one of the most common ailments to affect both children and adults, according to the Centers for Disease Control and Prevention (CDC), and conjunctivitis is a leading cause of children being absent from day care or school.

Contrary to popular belief, though, pink eye isn't always contagious. There are four different factors that can cause pink eye: an allergic reaction, a foreign substance in the eye, a viral infection or a bacterial infection.  

Viral conjunctivitis is the most common form of pink eye; it is caused by a cold virus, according to the American Academy of Ophthalmology. It can also be caused by the herpes simplex virus. Bacterial conjunctivitis is caused by a bacterial infection of the eye.

Allergic conjunctivitis is simply caused by allergens irritating the conjunctiva membrane. Any object in the eye, including contacts, dirt and liquids can also cause conjunctivitis. Allergic conjunctivitis and conjunctivitis caused by a foreign substance in the eye aren't contagious.

On the other hand, when it is caused by a bacterial or viral infection, pink eye can be very contagious. "It is spread when a person touches his or her own eye and then touches the eye of another person; or it is spread to the individual by touching the infection in one's own nose or sinus,"said Dr. Jill Swartz, practicing physician at GoHealth Urgent Care. 

Contrary to a popular urban myth, it is highly unlikely that farting on someone's pillow will cause pink eye, especially if the person who farted had clothes on. 

Even if the person who farted was naked, there is a very slim change that bacteria could transfer to your pillow, according to the Science in Our World blog at Penn State University. Also, you would have to immediately lay your head on the pillow, because bacteria dies quickly when it doesn't have a host. 

Pink eye is usually very easy to detect. When the membrane becomes inflamed, it produces mucus and tears to protect the eye. "It usually starts in a single eye with goopy, thick crusted discharge — you wake up and the eye feels sealed like glue," said Cindy Weston, an assistant professor at the Texas A&M Health Science Center College of Nursing.

The other most obvious symptom is reddened whites of the eye. Inflammation or swelling from pink eye makes blood vessels more visible, causing the redness. 

Pink eye can also cause itchy and watery eyes, a grainy feeling in the eye, discharge that forms a dry crust overnight, swelling of the eyelids, cloudy vision and light sensitivity. Symptoms can occur in one or both eyes, according to the Mayo Clinic

The symptoms can vary depending on the cause. Viral conjunctivitis usually comes on quickly and is typically associated with "cold" pink-eye-symptoms-treatmentsymptoms like runny nose, cough, sore throat, fever, congestion, said Weston.  

Bacterial conjunctivitis is often marked by thick, yellow-green discharge and can also exhibit cold-like symptoms.

Allergic conjunctivitis usually affects both eyes. The eyes will often feel watery, itchy and scratchy. The discharge is clear and may be accompanied by other allergy symptoms including itchy nose, sneezing and clear nasal drainage.  

Anyone who has pink eye symptoms should see a doctor if the symptoms don't clear up within 24 hours. Pink eye can often be treated at home, but should always be checked by a doctor since it is important to know the cause of the inflammation, according to the Mayo Clinic. Pink eye symptoms may be a sign of a more serious eye condition.

If the problem is caused by a bacterial infection, it will need a topical antibiotic ointment or solution. For viral and allergic conjunctivitis, the inflammation will go away on its own within two to three weeks. 

There are several at-home treatments that can provide some relief. Swartz suggested that it's best to wipe away the discharge with a warm cloth several times a day. 

A cold compress can also be used to sooth allergic conjunctivitis and a warm compress can be used to sooth viral or bacterial pink eye. Eye drops may also help alleviate dryness and help with swelling. Allergic conjunctivitis can be treated with an over-the-counter antihistamine. 

Contact lens wearers with pink eye should stop wearing their contact lenses until their eyes heal. They should also throw away any used contacts.

Pink eye is usually contagious until the tearing, discharge and matting of the eyes goes away. This can last up to two weeks.

Pink eye can be highly contagious, especially in children, so it is important to take steps to prevent infection. Dr. John Soud, owner and co-founder of Velocity Care Urgent Treatment Centers, provided these tips for preventing the spread of pink eye:

  • Never touch your eyes or the area around your eyes without washing your hands first.
  • Be sure to discard old cosmetics and anything that comes in contact with your eyes during an infection.
  • Never share makeup products.

Weston added that surfaces should be wiped down with disinfectant, and towels should be laundered after use to help prevent the spread of infection.

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