How Do I Know If My Sore Throat Is Viral or Bacterial?

Medically Reviewed on 2/28/2022

Bacterial and viral sore throats

Knowing whether your sore throat is viral or bacterial is usually determined by symptoms. Viral sore throats usually consist of a cough, swelling in the throat, and runny nose whereas bacterial sore throats are typically accompanied with nausea and vomiting, stomach ache, and there is no cough.
Knowing whether your sore throat is viral or bacterial is usually determined by symptoms. Viral sore throats usually consist of a cough, swelling in the throat, and runny nose whereas bacterial sore throats are typically accompanied with nausea and vomiting, stomach ache, and there is no cough.

A sore throat is something we’re all familiar with, but it’s not easy to tell if it’s because of a virus or bacteria. And this can confuse you when you’re trying to treat it.

A bacterial sore throat is called strep throat, caused by the streptococcus bacteria. It is contagious, spreading either through the air via droplets — like when someone coughs — or on surfaces that someone with the infection has touched.

On the other hand, a viral sore throat is caused by inflammation resulting from a virus, such as the common cold. It has entirely different symptoms and progression than a bacterial sore throat. It is still contagious, but it doesn’t respond to antibiotics the way a bacterial infection does. 

Almost everyone will experience a sore throat at some point, but certain lifestyle factors may increase your risk. Some of these are:  

  • Exposure to airborne irritants, especially air pollution or cigarette smoke
  • Not washing your hands frequently or thoroughly enough
  • Being in close contact with people who have colds or other upper respiratory infections

It’s important to have your sore throat symptoms reviewed by a doctor because an untreated infection can be dangerous. Many complications could arise, such as: 

Signs and symptoms of sore throat

The way you’re most likely to tell the difference between a bacterial and a viral sore throat is by the symptoms. Below are three symptoms each of bacterial and viral sore throats that do not appear in the other type.


Painful swallowing is common to both bacterial and viral sore throats, but bacterial sore throats often come with red and swollen tonsils at the back of the throat. You may very well also see white patches or streaks of pus there. Fever is also common to both, but the fever associated with bacteria tends to be higher and more severe than with a viral infection. 

Some people with a strep throat infection will also notice tiny red spots, called petechiae, on the roof of the mouth. These are actually tiny blood vessels, capillaries, that have broken as a result of the infection and are leaking little bits of blood. 

Here are some more common symptoms that distinguish a bacterial sore throat from a viral one: 

  1. Nausea and vomiting. A bacterial strep throat infection can cause nausea and vomiting. Loss of appetite is also a common symptom. Children especially are prone to nausea because of a strep throat infection. 
  2. Stomach ache. Although the throat and stomach may seem unrelated, stomach and abdominal pain is a common symptom of bacterial strep throat. The infection can cause a range of symptoms associated with indigestion, also called dyspepsia.
  3. No cough. It may sound counterintuitive, but bacterial sore throats seldom come with coughing. A few classic cold symptoms like cough and runny nose indicate a viral sore throat — so if you do have them, it’s probably not strep throat. 


A viral sore throat has a very different presentation. It imitates, and very often accompanies, the symptoms of the common cold

Here are some of the major signs to look for: 

  • Cough. Viral sore throats almost always have a cough, unlike their bacterial counterparts. The coughing is your body’s way of expelling foreign substances from your lungs and may last up to two weeks. 
  • Visible swelling in the throat. Viral sore throats will often be red and swollen at the back of the mouth, but there shouldn’t be red and white specks like there would be with a bacterial infection. 
  • Runny nose. Viral sore throats often accompany other common cold symptoms, especially runny noses and hoarseness

You can also expect to run a fever with a viral sore throat. In general, bacterial and viral sore throats can feel very similar to one another, but it may feel more like a cold if a virus is the cause. 

This is why an accurate medical diagnosis is necessary. 


Which illness is known as a viral upper respiratory tract infection? See Answer

Causes of sore throat

Viruses are the more common source of sore throats. Most of the time, it’s from flu or common cold viruses. That said, other viruses can also cause it — like chicken pox, measles, and mononucleosis, which are more serious and very contagious.

If your infection is bacterial, it is most likely strep throat at the back of the throat and tonsils.

Diagnosing Sore throat

Rapid strep screening is a common way of diagnosing strep throat. It involves taking a quick sample from the back of your throat and only takes about five minutes for the results to be ready. 

To eliminate the possibility of a false negative on the rapid strep test, doctors may also use a throat culture. Sample cells are placed in a growth medium, and their development is observed by a trained technician. The results of this lab work will determine your course of treatment.

Treatments for bacterial and viral sore throats

If your lab results indicate a viral sore throat, your doctor won’t prescribe any antibiotics. You’ll unfortunately have to wait it out from there, but doctors often do recommend a number of therapies to help, such as: 

  • Hot teas and broths to soothe the throat
  • Sleeping in a slightly elevated position to improve mucus drainage
  • Over-the-counter pain medications to treat your ancillary symptoms and relieve your discomfort
  • Gargling with warm water

But some medical intervention will be necessary if the infection is bacterial. Your doctor will probably prescribe antibiotics to target the bacteria directly. Your recovery can take up to a week, so be patient with your body and get the rest you need.

Sore throat - should I take antibiotics?

A sore throat is irritation and scratchiness in the throat accompanied by pain that often worsens with swallowing. A sore throat is often the first warning sign of an infection. The most common cause of a sore throat is a viral infection. Rarely, a bacterial infection can cause a sore throat. A sudden, severe sore throat without coughing, sneezing, or other cold symptoms may be an indication of a bacterial infection, usually caused by Streptococcus bacteria. Hence, it is called a strep throat.

What are different types of sore throat?

Sore throats may be divided into three types based on the part of the throat they affect

  • PharyngitisIt affects the area right behind the mouth.
  • TonsillitisSwelling and redness of the tonsils, the soft tissue in the back of the mouth. Sometimes, white patches or areas of pus will form on the tonsils. These white patches are more common in strep throat than in a sore throat caused by a virus.
  • Laryngitis: Swelling and redness of the voice box or larynx.

What are the common causes of a sore throat?

Causes of sore throats range from infections to injuries. Below are the most common causes of a sore throat

  • Viral infection: Viruses cause about 90% of sore throats. Common cold and influenza are the most common viral infections that may cause a sore throat. 
  • Bacterial infection: A Streptococcus bacterium is the most common cause of a sore throat due to a bacterial infection. Strep throat causes nearly 40% of sore throat cases in children. Tonsillitis and sexually transmitted infections such as gonorrhea and chlamydia can also cause a sore throat.
  • Allergies: Usually, the immune system reacts to allergy triggers such as pollen, grass and pet dander. It releases chemicals that cause symptoms such as nasal congestionwatery eyes, sneezing and throat irritation. Excess mucus in the nose can drip down the back of the throat. This is called postnasal drip and can irritate the throat.
  • Injury: Any injury, such as a hit or cut to the neck, can cause pain in the throat. Getting a piece of food stuck in your throat can also irritate it. Repeated use strains the vocal cords and muscles in the throat. A person can get a sore throat after yelling, talking loudly or singing for a long period of time.
  • Tumor: A tumor of the throat, voice box or tongue may cause a sore throat. When a sore throat is a sign of cancer, it doesn’t go away after a few days.
  • Gastroesophageal reflux disease (GERD): It is a condition in which acid from the stomach backs up into the esophagus (the tube that carries food from the mouth to stomach). The acid burns the esophagus and throat and may sometimes cause a sore throat.
  • Dry air: Dry air can suck moisture from the mouth and throat and leave them feeling dry and scratchy. The air is most likely dry in winter when the heater is running.
  • Smoke, chemicals and other irritants: Many different chemicals and substances in the environment irritate the throat, including cigarette and other tobacco smoke, air or traffic pollution, cleaning products and other chemicals.

Should I take antibiotics for a sore throat?

Antibiotics cannot treat a sore throat if it is caused by a viral infection. Viruses cause about 90% of sore throats; hence, antibiotics should not be used immediately as treatment for a sore throat. Antibiotics may also cause side effects such as diarrhea, vomiting and skin rashes. Sore throats caused by a viral infection usually go away on their own in four to five days. Excessive antibiotic use may also render the antibiotic ineffective when it is needed.

A doctor may prescribe antibiotics such as penicillin if a sore throat is caused by a bacterial infection. However, a strep throat goes away in three to seven days with or without antibiotics. 

Antibiotics may not make a person better faster. It lowers the risk of a bacterial infection spreading to another individual or other parts of the body such as the ears and sinuses. They may also prevent serious but rare problems such as rheumatic fever in children.

How can I treat a sore throat without antibiotics?

A sore throat usually lasts less than a week. If a sore throat lasts more than four days, medical attention may be required. Below are few remedies to soothe the throat

  • Suck on lozenges (only in children older than two years old).
  • Use a clean humidifier or cool mist vaporizer.
  • Gargle with warm salt water.
  • Drink warm beverages and plenty of fluids.
  • Use honey to relieve cough for adults and children at least one year of age or older.
  • Get plenty of rest.
  • Take over-the-counter medicine such as acetaminophen or ibuprofen to relieve pain and reduce fever.

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Medically Reviewed on 2/28/2022
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