It is a highly contagious disease if the underlying cause is a bacterial or viral infection. In some cases, however, it is not contagious.
This applies when the cause of inflammation is exposure to chemicals or foreign objects such as smoke or dirt that get into your eye.
How long conjunctivitis lasts depends on what type you have, what caused it, and how you treat it. Most of the time, pink eye clears up in a few days to two weeks.
Pink eye is generally contagious as long as you have symptoms, common symptoms of pink eye can last from a few days to a few weeks.
Many types of conjunctivitis are contagious, but only after symptoms, such as redness, tearing, and crusting, appear. These symptoms should improve within 3 to 7 days.
It appears that people are not contagious during the incubation period of conjunctivitis, that is, the time that passes up to a few days between exposure and when symptoms begin.
Contagion of conjunctivitis during the incubation period
There is really no set period of time before symptoms of viral conjunctivitis appear, but it is accepted that viral conjunctivitis generally takes between 12 hours and three days to manifest.
The viruses and bacteria that cause pink eye can spread easily, but during the incubation period, you still won’t be able to spread it to people.
However, be careful as once symptoms start to appear, you are automatically contagious and therefore should seek treatment immediately before the condition worsens.
The duration of contagion also depends on the source. If you have been infected by bacteria, it is immediately contagious once symptoms appear, and continues to be so for a full day after treatment.
If the cause is a virus, you are contagious throughout the illness and will have to let it run its course, which is usually around two weeks.
If the conjunctivitis is caused by bacteria, the incubation period is usually one to three days. Depending on other environmental factors, the period can even take up to 14 days.
There are several types of conjunctivitis, including viral and bacterial:
If your pink eye is caused by a common viral infection and there are no other complications, then it should clear up in a few days to two weeks.
Viral conjunctivitis is caused by viruses such as adenovirus and herpes virus. It usually goes away without treatment in 7 to 14 days.
It tends to occur in both eyes and often accompanies a common cold or respiratory tract infection.
More serious causes include the herpes simplex virus (which usually includes skin blisters), varicella-zoster virus (chickenpox and shingles), and rubella (measles).
With viral conjunctivitis, symptoms usually get worse about three to five days after the eye infection begins.
Pink eye can also be caused by bacterial pink eye, which, even with treatment, such as prescription antibiotic drops, can last up to a month or more.
However, with this type of conjunctivitis, people should no longer be contagious 24 hours after antibiotic treatment begins.
The bacterial conjunctivitis is caused by an infection with bacteria such as Staphylococcus aureus or Streptococcus pneumoniae.
Antibiotics should begin to clear up the infection within 24 hours of starting use. Even if you don’t use antibiotics, mild bacterial conjunctivitis almost always gets better within 10 days.
Using antibiotics for a bacterial infection clears symptoms faster, but will not be helpful in treating viral infections or other causes of pink eye.
You may need eye drops that contain decongestants or antihistamines to reduce irritation and swelling, sometimes for a week or two. You are no longer contagious when your eyes look and feel normal again.
How long do the other types of conjunctivitis last?
If your eye infection is not due to viral or bacterial causes, then you may have allergic conjunctivitis.
In that case, conjunctivitis from allergic reactions to pollen, dust, and animal dander can last indefinitely, especially depending on the time of year.
Allergic conjunctivitis is not likely to go away on its own unless you eliminate or prevent the cause of the reaction.
In the meantime, you may consider using eye drops that contain antihistamines to ease the symptoms of the allergic reaction. Allergy drops are available without a prescription or with a prescription from your eye doctor .
When in doubt about what is causing your pink eye, always consult your ophthalmologist.
Viral conjunctivitis vs. bacterial conjunctivitis
A virus that causes pink eye can be spread from the nose to the eyes, or it can be spread when someone sneezes or coughs and the drops come into contact with the eyes.
Bacteria cause bacterial conjunctivitis. Usually, the bacteria are spread to the eyes from the respiratory system or the skin. You can also get bacterial conjunctivitis if:
- You touch your eyes with dirty hands.
- You apply makeup that has been contaminated with bacteria.
Both types of pink eye often begin during an upper respiratory infection, such as a cold (virus) or sore throat (virus or bacteria).
Both viral and bacterial conjunctivitis cause the same general symptoms, including:
- Pink or red color to the whites of the eyes.
- Itching or itchy sensation in the eye.
- Burning or irritation.
- Crusting of the eyelids or eyelashes, especially in the morning.
- Discharge from the eye
Here are some ways to tell what type of pink eye you have:
It usually starts in one eye but can spread to the other eye, starts with a cold or other respiratory infection, causes a watery discharge from the eye.
It can start with a respiratory infection or an ear infection , affects one or both eyes, causes a thick discharge (pus) that causes the eyes to stick together.
Your healthcare provider can determine if you have a bacterial or viral infection by taking a sample of the discharge from your eye and sending it to a laboratory for testing.
Most cases of bacterial and viral conjunctivitis will improve without treatment in a few days to two weeks.
To relieve symptoms in the meantime:
- Use artificial tears or lubricating eye drops to prevent dryness. (Discard the bottle once your infection has cleared so you don’t re-infect yourself.)
- Keep cold compresses or warm, moist compresses on your eye to reduce swelling.
- Wipe the discharge from your eyes with a wet cloth or tissue.
For more severe pink eye, your healthcare provider may prescribe medications:
- Viral conjunctivitis that is caused by the herpes simplex virus or varicella-zoster can respond to antiviral medications.
- Antibiotic eye drops or ointments can help eliminate severe cases of bacterial conjunctivitis.
To avoid getting reinfected, follow these steps once the pink eye clears up:
- Throw away the makeup applicators or eye makeup that you used while you were infected.
- Throw away the disposable contact lenses and the solution you used while you had pink eye.
- Clean and disinfect hard contact lenses, glasses, and cases.
To avoid catching or transmitting the infection:
- Wash your hands often throughout the day with warm soapy water or use an alcohol-based hand sanitizer.
- Wash your hands if you come in contact with the eyes, clothing, or other personal items of an infected person.
- Do not touch or rub your eyes.
- Don’t share personal items like towels, blankets, pillowcases, makeup, or makeup brushes.
- Wash bedding, washcloths, and towels in hot water after use. Thoroughly clean contact lenses and glasses.
- If you have pink eye, stay home from school or work until your symptoms go away.
When to see your doctor
Most cases of mild conjunctivitis get better with or without treatment and do not cause any long-term problems. Severe conjunctivitis can cause swelling of the cornea, the clear layer in the front of the eye. Treatment can prevent this complication.
Consult your healthcare provider if:
- Your eyes are very painful, you have blurred vision, sensitivity to light or other vision problems, your eyes are very red.
- Your symptoms don’t go away after a week without medication or after 24 hours with antibiotics, your symptoms get worse.
- You have a weakened immune system due to a condition such as cancer or HIV or from the medications you take.
Conjunctivitis is a common eye infection that is often caused by bacteria or viruses. More severe cases may need treatment with antibiotics or antiviral drugs.
Practicing good hand washing hygiene and not sharing personal items can prevent the spread of pink eye.
Can newborns have conjunctivitis?
Newborns can develop conjunctivitis, which is called neonatal conjunctivitis, or less commonly, ophthalmia neonatorum. Common symptoms include eye discharge and red eyelid swelling between one day and two weeks after birth.
Symptoms often appear 5 to 12 days after birth, but can occur at any time during the first month of life.
Gonococcal conjunctivitis is caused by Neisseria gonorrhoeae, the bacteria that cause gonorrhea. Gonococcal conjunctivitis causes pus discharge and swelling of the eyelids, which can appear 2 to 4 days after birth.
Chemical conjunctivitis can be caused by eye drops or ointments given to newborns to help prevent bacterial eye infections. Symptoms include red eyes and eyelid swelling, and they usually resolve within 24-36 hours.