Viral vs. Bacterial Conjunctivitis (Pinkeye)

Whatever the cause may be, pinkeye — or what’s referred to medically as conjunctivitis — is uncomfortable. And the hallmark pink or red appearance of the “white” of the eye caused by irritation can make any sufferer self-conscious as well.

“Conjunctivitis basically means inflammation of the conjunctiva, which is the clear part that covers the white part of the eyes,” says Dr. Sumitra Khandelwal, an associate professor of ophthalmology at the Cullen Eye Institute within the Baylor College of Medicine in Houston and medical director for the Lions Eye Bank of Texas. “When you’re looking at somebody, the white part of the eye actually has a clear covering to it, and that can get inflamed.”

In some cases, pinkeye may result from an allergic reaction. Things like mold and pollen may trigger it in seasonal allergy sufferers, for example. In other cases, chemicals in the environment — outside or in the home, from air pollution to eye makeup — may be to blame.

But the majority of the estimated 3 to 6 million cases of conjunctivitis that occur annually in the U.S. are infectious. They result from a viral or bacterial infection. And viral pinkeye is the most common type of conjunctivitis of all, accounting for the lion’s share of conjunctivitis cases in adults.

The distinctions aren’t merely a way to categorize the infection either. Instead, experts note, it’s important to know what causes pinkeye to determine how to treat it — or if it needs to be treated at all.

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Viral or Bacterial?

In many ways, the symptoms of pinkeye are similar irrespective of the cause. However, experts say some signs may point to viral or bacterial conjunctivitis. Those include:

Cold or upper respiratory symptoms. These often accompany viral conjunctivitis.

Copious discharge from the eye. Lots of pus or a yellowish discharge could indicate it’s bacterial.

Age. The vast majority of pinkeye cases involving adults are viral. Kids get a more evenly mixed distribution of bacterial and viral conjunctivitis.

Coloration of the white of the eye. Lighter discoloration — like salmon color — may be viral; a darker, reddish color may be bacterial.

Perhaps the most obvious sign for viral pinkeye is if it’s accompanied by a cold or upper respiratory infection, experts say. If you have those symptoms — which could range from cough to sore throat — as well as classic pinkeye symptoms, you likely have the viral version of pinkeye. In contrast, bacterial pinkeye tends to be associated with more discharge that’s thick, often a yellow or green color, with pus, which can cause the eye to crust over.

If you have viral pinkeye, there’s a good chance you’ll have it in both eyes. “Viral (conjunctivitis) tends to be more commonly bilateral, though it can be in one eye,” says Dr. Kamran Riaz, an ophthalmologist and clinical associate professor of ophthalmology at the Dean McGee Eye Institute at the University of Oklahoma. “Whereas bacterial tends to be usually just one eye, though it can be in both eyes.”

Comfort Care for Viral Pinkeye

As with the common cold, there’s no proven cure for viral conjunctivitis. In fact, the adenovirus that causes cold symptoms is frequently to blame for viral pinkeye.

“Viral conjunctivitis will be treated with what we would call comfort care,” says Dr. Jeff Pettey, an ophthalmologist and associate professor of ophthalmology and visual sciences at the University of Utah. “You can do something like a cool compress — a washcloth in cold water — just for comfort. You can use artificial tears for comfort as well.” Artificial tears lubricate the eye, which can dry with pinkeye.

Viral pinkeye tends to go away on its own. It usually clears up within a matter of days to two weeks. In some instances, however, symptoms can persist for longer. If symptoms persist or worsen, seek care from your medical provider. Topical antihistamines may provide some relief.

Steroids are specifically not recommended for use in these instances, as they could prolong the course of disease. “Patients may still have the virus in the eye for a longer period of time,” Riaz says, because the steroid blunts the immune system response to the eye infection. “So the steroids can kind of help you feel a little bit better.” But he and other experts note they can also keep you infectious for longer.

Betadine — an antiseptic that can kill bacteria and viruses and is used during eye procedures like cataract surgery — is also sometimes given as an eye wash to treat severe viral pinkeye. Betadine may be used, for example, when pseudomembranes, or false membranes, form over the white of the eye, causing significant pain.

“That’s been used with increasing frequency and success,” Riaz says. But it’s administered in the doctor’s office — it’s not the same thing as buying betadine at your local pharmacy and applying to your eye yourself. “There isn’t anything commercially available, so it really has to be compounded or formulated by an eye care provider, and not everybody knows how to do that.”

The eye wash is also uncomfortable: “Sometimes the treatment is a little bit worse than the actual pinkeye because betadine burns,” Khandelwal says.

Clinicians emphasize that for the vast majority of people who have viral pinkeye, basic comfort care is the best course.

There’s no current treatment approved by the Food and Drug Administration for treatment — eye drops or otherwise — for viral conjunctivitis. “There could be treatment in the future for (viral) pinkeye,” Khandelwal says. “But much like the common cold, there’s just so much that goes into it as far as different strains and how viruses change every year that it would take a lot of work to get there — to have a drop that would fix pinkeye.”

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Treating Bacterial Conjunctivitis

Unlike with viral pinkeye, experts recommend treating bacterial conjunctivitis.

Antibiotics, delivered in eye drop or ointment form, are a common course of treatment. However, experts caution that while primary care providers may be equipped to treat pinkeye, it’s important to ensure the cause of conjunctivitis has been properly determined first. And eye doctors are best equipped to make that determination.

That’s important to note, experts say, because research indicates that often antibiotics are prescribed to treat pinkeye when that isn’t the right approach — like when the conjunctivitis is, in fact, viral. Patients who saw primary care providers for conjunctivitis were more likely to fill a prescription for antibiotics than those who saw an ophthalmologist, according to a 2017 study published in the journal Ophthalmology, the journal of the American Academy of Ophthalmology. Researchers concluded this may promote antibiotic resistance, making bacterial strains hard to treat in the future — not to mention exposing those with viral conjunctivitis to unnecessary drug side effects.

For those who do have bacterial pinkeye, treating it is important to prevent possible complications. Most commonly, bacterial conjunctivitis is caused by strains such as staphylococcus aureus, streptococcus and haemophilus. “Those are actually natural occurring bacteria that we all have on our hands and our eyelashes, and so sometimes you’ll get an overgrowth and you’ll develop conjunctivitis from that,” Khandelwal explains.

In addition, If you wear contact lenses, you’re at risk to have a more serious eye infection caused by the bacteria pseudomonas. Treating that bacterium requires more broad spectrum antibiotics drops and you should not wear contacts until your symptoms have resolved. Always use new, clean contacts and a new clean contact case to avoid reinfection.

There’s special concern around bacterial pinkeye that’s caused by sexually transmitted diseases, such as chlamydia and gonorrhea, which can threaten vision. A person may develop pinkeye when genital fluids like semen come in direct contact with the eye or through indirect contact, like touching the eye after sex. In cases where pinkeye is caused by an STD, it’s especially important to treat it early and aggressively. Oral antibiotics may be used.

In addition to STDs being spread through sexual contact and ultimately leading to conjunctivitis, newborns may also get these type of pinkeye infections during delivery.

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When to Seek Medical Attention Right Away

Prophylactic treatment of conjunctivitis is standard for babies born in hospitals in the U.S., and parents should take infants who develop pinkeye to the doctor for prompt evaluation and treatment. That’s because if it’s not treated it can cause serious complications, such as vision loss, particularly if due to gonorrhea or chlamydia.

In general, if you or your child have any of the following symptoms associated with pinkeye, make sure to seek medical attention right away:

— Decreased or blurred vision.

— Eye pain.

Light sensitivity, especially if it’s more severe.

— Copious discharge from the eyes.

— Worsening symptoms.

In some cases, discharge may make it difficult to open the affected eye or eyes. When light sensitivity is severe — meaning you’re drawing the shades and trying to keep it dark — that could be a sign of a more serious problem. The infection may have spread in the eye beyond the conjunctiva or you may be experiencing another health issue that could threaten sight. For example, increasing pain and light sensitivity could point to an ulcer, or open sore, in the eye. “The consequences of an ulcer that goes untreated can be permanent scarring and vision loss,” Pettey says.

So while most pinkeye cases don’t have long-term consequences, experts emphasize that you should take warning signs seriously. Whether they indicate you have conjunctivitis or something else entirely, clinicians stress that worries about vision or other eye symptoms shouldn’t be overlooked. Instead, see an eye doctor if you have worsening symptoms or other concerns.

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Viral vs. Bacterial Conjunctivitis (Pinkeye) originally appeared on

Update 09/09/21: This story was previously published at an earlier date and has been updated with new information.

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