How Can You Tell the Difference Between a Viral and Bacterial Sore Throat

As cold and flu season approaches, many people have symptoms that include a sore throat. Viruses are the most common cause of a sore throat. Bacterial sore throat, or strep throat, is more common in children. But adults can get it, too. Especially if you're a parent or you work in close contact with kids.

Some symptoms and treatments for viral pharyngitis and strep throat are the same. But antibiotics will only work for strep throat. So it helps to understand a few ways they can differ.

How can you tell if a sore throat is viral vs. bacterial?

Symptoms like sore throat typically peak about 3 to 5 days after you first come down with a viral or bacterial illness. And both kinds of sore throat (also called pharyngitis) can last up to 10 days.

We'll take a closer look at the similarities and differences between the two in the next section. But here's a quick glance at how sore throat symptoms are likely to play out for most people.

Viral vs. bacterial sore throat: Key differences

A sore throat may feel similar if it's caused by bacteria or a virus. It can be achy, scratchy, or burning. But some of the other symptoms that go along with the sore throat may give a clue as to which one you're dealing with. Below we go through the key differences in the causes, symptoms, and treatment of a viral versus bacterial sore throat.

Causes

Between 50% and 80% of all sore throats are caused by a virus. Most of these are the same types of viruses that cause the common cold. But other sore throat conditions from viruses include:

• Influenza (flu)

• COVID-19

• Hand, foot, and mouth disease (more common in kids, can cause painful sores in the mouth and throat)

• Mononucleosis (more common in teens and young adults)

When a sore throat is caused by a bacteria, it's almost always group A Streptococcus pyogenes. This is usually shortened to group A strep. Or just plain strep throat.

An acute sore throat is usually caused by a bacteria or virus. Acute means that it happens suddenly and lasts a couple of weeks or less. A sore throat that lasts longer may have other causes that need medical attention. If a sore throat lasts more than 2 weeks, it might be caused by a different medical condition. Some causes of a chronic sore throat include:

• Allergies

• Gastroesophageal reflux disease (GERD)

• Environmental irritants (chemicals, cigarette smoke, air pollution)

• Dry air

• Tonsil stones

• Tumors

A sore throat that doesn't go away should be checked out by a healthcare professional.

Symptoms

Sometimes a sore throat caused by strep is more painful than when it's caused by a virus. But not always.

People with strep throat may have a higher fever. But if the sore throat is because of the flu or COVID, that can result in a high temperature, too.

One big clue is that strep throat doesn't usually come with the other symptoms of a cold or flu. For example, if you also have a stuffy nose and a cough, it's more likely to be a virus and less likely to be strep throat.

In fact, healthcare professionals sometimes use a method called a Centor score to help figure out if a sore throat is viral or bacterial. You're more likely to have strep throat if you:

• Are between the ages of 3 and 15 years

• Have pus or swelling of the tonsils

• Have tender or swollen lymph nodes in the neck

• Have a fever higher than 100.4°F (38°C)

• Do not have a cough

Diagnosis

To diagnose strep throat, a healthcare professional will first ask questions about your symptoms. And they'll take some other factors into account like:

• Your age: Strep throat is most common in kids between 5 and 15 years. Strep throat is uncommon in children younger than 3 years. Some groups of adults may be at risk if they're in close contact with children in that age group.

• The time of year: Strep throat is more common in colder months - the late fall, winter, and early spring. They'll also consider other infections that may be going around, especially flu and COVID.

• Exposures: If you've been around someone with strep or a viral infection, that may give an additional clue.

• Is it getting worse? Both strep and viruses can stick around for a while. But if your sore throat is getting worse, they'll want to check that there's no complication, like an abscess.

Next, you'll have a physical exam. If it looks like strep is a possibility, you'll probably have a rapid strep test done first. To do this test, a healthcare professional will use a thin swab to collect saliva from the back of the throat. It takes about 10 to 20 minutes to get the results.

Sometimes, a test called a throat culture is done at the same time. If the rapid test is negative, but strep is still a concern, they may send the throat culture to a lab to be sure. The culture will check if any bacteria grows from the sample that was taken. Those results take from 24 to 48 hours.

If your symptoms seem more like a virus, you may or may not have other tests done. If it looks like your sore throat is part of a common cold, there's no need for more testing. But you may also be tested for:

• COVID-19

• Influenza (flu)

• Mononucleosis (mono)

Treatment

Antibiotics are used to treat strep throat. They can shorten the time you feel sick by about 1 day. And most people no longer can spread strep to others after taking antibiotics for 24 hours.

It's especially important for kids to get antibiotics if they have strep. This is because strep throat can lead to some rare but serious complications, like scarlet fever.

There are a few different antibiotics that can treat strep throat:

• The most common antibiotics are penicillin and amoxicillin.

• People with a mild allergy to penicillin may be able to take cephalexin.

• People with more severe allergies may take azithromycin or clindamycin.

If a sore throat is from the flu or COVID, people with risk factors for more severe symptoms may take antiviral treatments.

But if your sore throat is from one of the many viruses that cause a cold, supportive care is best. Antibiotics won't work to treat a virus. They could even make you feel worse with side effects like nausea, diarrhea, or a rash. And too many antibiotics over time can lead to antibiotic resistance. That means that future infections could be harder to treat.

There are things you can do to treat your sore throat symptoms, whether it's caused by a bacteria or a virus:

• Eat foods that ease throat pain. Focus on soft foods like soup, yogurt, oatmeal, or cooked vegetables. Some people find warm food and drink more soothing, like hot tea or broth. Others prefer cold foods, like ice cream and popsicles. Avoid anything that's hard, crunchy, or acidic. Honey is another good option for adults and children older than 12 months.

• Try saltwater gargles. Mix half a teaspoon of salt in a glass of warm water. Gargle and then spit it out. Don't swallow the salt water. Try to gargle several times a day.

• Try some over-the-counter (OTC) options.Medications like ibuprofen, naproxen, or acetaminophen can help with pain and fever. Cough drops, lozenges, or numbing sprays may soothe throat irritation.

• Get your rest. Stay home from work or school if you can until you feel better.

Duration

After 1 week, 85% of people with a sore throat feel better. That includes sore throat from viruses and from strep.

If you're prescribed antibiotics or antiviral medication, it's important to take it until it's gone. You might start feeling better after a day or two. But if the bacteria or virus isn't fully treated, it could come back again.

Things that help to prevent spreading infection to others will also lower your risk of being infected again. These include:

• Don't share cups, plates, or silverware.

• Avoid close contact with others when possible, especially if you have a fever.

• Wear a mask or avoid breathing, coughing, or sneezing on others.

• Wash your hands often.

When to see a healthcare professional

Most cases of a mild sore throat can be treated at home. Especially if the sore throat goes along with other symptoms that seem like a cold.

But there are times you'll want to call a healthcare professional to at least discuss your symptoms. And see if they recommend that you come in for a test.

Because kids have a higher risk of strep throat, call or see a healthcare professional if:

• Your child has a fever higher than 101°F (38.3°C).

• It's strep throat season - late fall, winter, or early spring.

• Your child has a sore throat without a cough or other cold symptoms.

• Your child has a stiff neck, trouble breathing or swallowing, or problems opening their mouth.

• You or your child has been in contact with someone who has strep throat.

• You're concerned about your child's eating and drinking, symptoms, or energy level.

Adults should call a healthcare professional if they have a sore throat and:

• Pain that's getting worse or not improving after 2-3 days

• A fever higher than 100.4°F (38°C)

• Trouble breathing or swallowing

• Neck swelling

• Health conditions that could put you at risk for more severe infections

Frequently asked questions