How long is conjunctivitis contagious?
If you have conjunctivitis caused by a virus or bacteria, your conjunctivitis can be contagious for several days to several weeks once symptoms (red, itchy, watery eyes; possibly with eye discharge) appear.
Schools and child care often require a child diagnosed with conjunctivitis to stay home until the condition is resolved. This is a good idea, because infectious conjunctivitis can be highly contagious in environments in which children are in close contact with each other.
Determining how long conjunctivitis is contagious and how long you or your child should stay home can be a little tricky. Generally speaking, it should be safe for you to return to work or for your child to return to school or day care if the obvious symptoms of conjunctivitis no longer are present — usually in three to seven days.
This means that eyes should be clear of yellowish discharge and matter on the eyelashes as well as the corners of the eyes. Also, any redness in the white of the eye should be cleared up.
Contagious conjunctivitis treatments
Topical antibiotic ointments or eye drops are effective treatments for conjunctivitis only if the conjunctivitis is caused by bacteria. In this case, you need up to 24 hours for the eye drops or ointment to start working and for the conjunctivitis to no longer be contagious.
If conjunctivitis is caused by a virus, the infection simply must run its course. While there is no treatment for viral conjunctivitis, you can relieve symptoms with lubricating eye drops to soothe irritation.
If your conjunctivitis is caused by eye allergies, then the condition is not contagious but you should consult with your optometrist to make sure you know which type of conjunctivitis you or your child has.
If eyes are red from an allergic reaction, eye drops containing antihistamines may be able to relieve symptoms. Cold compresses can also help.
Exposure to contagious conjunctivitis
It's difficult to determine exactly how long conjunctivitis is contagious if you don't know its cause.
For example, the rubeola virus causing measles and accompanying conjunctivitis symptoms is extremely contagious, often for as long as two weeks or more.
You also can be at risk of getting contagious conjunctivitis from exposure to certain adenoviruses found in water sources such as untreated swimming pool water. This is a good reason to wear swimming goggles or a mask with a seal that prevents your eyes from being exposed to the water.
You or your child also can be infected with exposure to bacteria and viruses found in the environment, such as contaminated towels or bench tops.
The risk of environmental exposure can last for weeks unless contaminated items are cleaned and disinfected. This is why it's a good idea to discard items such as mascara brushes and other eye makeup if you've had infectious conjunctivitis, even if your eyes have cleared up.
If you are being treated but don't notice any improvement in your conjunctivitis symptoms after about 10 days, contact your optometrist.
Page updated November 2020