January 17, 2024

Getting sick is an unpleasant experience that everyone dreads. Although symptoms may overlap between illnesses, it can be difficult to know what you’ve come down with.

Strep throat and the flu are common illnesses that can make you feel run down and fatigued and cause a variety of other symptoms. Yet, each of these conditions is very different on a biological level.

In this guide, we’ll explore the differences between strep throat vs. flu viruses. Additionally, learn more about what to do if you’re sick with either of these illnesses and when you should seek medical help.


Biological differences between strep vs. flu virus

One of the most common misconceptions surrounding the flu and strep is that both are viruses. Viruses and bacteria are two unique things. Bacteria are single-celled organisms that can survive on their own, whereas viruses require a host (in this case, humans) to survive.

“Strep” or “strep throat” is short for the name of the bacteria that causes the illness, known as Streptococcus pyogenes. This highly contagious bacteria spreads throughout the air. This means when someone coughs or sneezes, the bacteria enters the air.

Unlike strep, which is a bacterium, the flu is caused by the influenza virus. This viral respiratory illness spreads through the air via droplets, just like strep. For otherwise healthy individuals, mild cases of the flu go away on their own without any complications. However, vulnerable populations such as the elderly or those with impaired immune systems may have a harder time fighting off the influenza virus.

Why it matters

You might be asking yourself, “Why does it matter?” Differentiating between strep throat vs. flu is important because it dictates the treatment for each.

Bacterial illnesses such as strep throat require different treatments than viral illnesses such as the flu. For example, antibiotics should not be prescribed for viral illnesses like the flu but can be helpful for bacterial infections such as strep throat. Misuse of antibiotics and improper use for viral illnesses can lead to antibiotic resistance.

As a patient, understanding which illness you have can also help you understand what symptoms to expect.


Differences between strep vs. flu

The unique symptoms of both strep and the flu can help you to determine which illness you might have. While every illness affects patients differently, strep throat tends to cause more severe and uncomfortable symptoms than the flu. Symptoms of strep throat and the flu in adults may be less severe than in children and infants.

Symptoms of strep throat

Strep throat generally comes on suddenly.1 The most common symptoms of strep throat include:

  • Extremely painful sore throat
  • High temperature/fever
  • Painful swallowing
  • Neck stiffness
  • Tiny red spots on the roof of the mouth
  • Swollen lymph nodes/jaw pain
  • Red tonsils with white patches

You may experience one or multiple of these common strep throat symptoms. Other symptoms that may occur with strep throat include headache, bad breathe, rashes, loss of appetite, fatigue, or trouble sleeping. If strep throat is left untreated, complications such as kidney damage could occur. The symptoms of strep throat often are not like common cold symptoms, which means you’re unlikely to experience a cough or runny nose.



Symptoms of flu

The flu virus often causes symptoms that are more similar to a common cold than strep throat. Flu symptoms come on suddenly2 and may include:

  • High temperature/fever
  • Fatigue
  • Painful body or muscle aches
  • Sore throat
  • Sweating or chills
  • Headaches
  • Sneezing, runny nose, or cough
  • Dehydration

The flu mostly causes respiratory symptoms. However, it can cause digestive issues like vomiting, diarrhea, or stomach pain in some people. Other less common flu symptoms include dizziness, lightheadedness, or ear infections.


Similarities between flu vs. strep

The differences between flu vs. strep are not always easy to spot. Both strep and flu may cause a sore throat and cause you to have a high fever.3 Fever can run as high as 104°F in severe cases.

In addition, both strep and the flu can make you feel more tired than normal and cause headaches. You may find that your body needs more rest than usual as it works to overcome the illnesses. Beyond these similarities, however, the flu and strep generally have distinguishable symptoms.

Simultaneous illnesses

It is important to understand that strep and the flu are two unique illnesses caused by bacteria and a virus. However, you could come down with both at the same time. When you are sick, and your immune system is impaired, you may be more likely to pick up other illnesses that occur simultaneously. Although possible, it’s more likely that you have either strep throat or the flu than to have both at once.

What to do if you’re sick

Regardless of which illness you have, getting lots of rest, drinking plenty of fluids, and trying to maintain good nutrition can help you feel better.4 In most cases, viral illnesses such as the flu will pass on their own within four to seven days. However, some instances may require the use of antiviral drugs to help shorten the duration of symptoms.

Not sure which illness you have? If symptoms do not gradually improve on their own, it may be time to seek help from your primary care physician. Scheduling an appointment with your primary care provider can help ensure you get the appropriate treatment for your illness.


Prevention of strep throat and the flu

There is no way to fully prevent getting sick with strep throat or the flu.3 However, there are things you can do to boost your immune system and reduce your chances of getting sick. Always wash your hands for at least 20 seconds with warm water and soap to reduce bacteria. Avoid contact with anyone who you know is sick, and keep your hands away from your face whenever possible.

Proper hand washing is also important to help reduce your chances of getting the flu. The flu virus has a vaccine that can help protect you against the influenza virus.

Getting the yearly flu vaccine can help your body develop antibodies that protect you against the virus. Since the flu and strep throat both spread via the air, stay home when you’re feeling sick. Cover your mouth and nose when near other people to help prevent the spread of illness.

Lifestyle choices and practices also play a big role in supporting or weakening your immune system.1 A weakened immune system can make you more susceptible to flu or strep throat. Eating a healthy, well-rounded diet with fresh foods can help ensure you get enough nutrition. Maintaining a solid sleep routine and good sleep practices are also important to support your immune system. Avoiding other unhealthy choices, such as smoking or excessive alcohol consumption, can also help protect your immune system.

Seeking medical help

Even medical professionals cannot always tell the difference between strep throat vs. flu without diagnostic testing. Your doctor may perform a strep screening or culture, which involves swabbing the inside of your mouth for bacteria. This helps search for the presence of the Streptococcus pyogenes bacteria. A rapid strep test can give nearly immediate results but may not be as accurate as a throat culture.

The flu is sometimes diagnosed via a rapid influenza test, which can produce results within 15 to 20 minutes. A healthcare professional must perform these tests for accurate results.

Many mild cases of the flu or strep throat can be managed at home. However, moderate to severe cases may require a trip to your primary care physician. Seeking medical treatment for the flu or strep throat may also help shorten the duration of your illness. Strep throat can be treated with various antibiotics, decreasing the time you are sick and making you feel better sooner.

If you are not feeling well, reach out to Healthcare Associates of Texas to make an appointment right away. Our medical staff can help identify whether you’re sick with the flu or strep throat and provide appropriate treatment. Other illnesses, such as the common cold and COVID-19, may also cause overlapping symptoms with these conditions.



  1. “Strep Throat – Symptoms & Causes – Mayo Clinic.” 2022. Mayo Clinic. November 30, 2022. https://www.mayoclinic.org/diseases-conditions/strep-throat/symptoms-causes/syc-20350338.
  2. “Strep Throat.” 2019. Yale Medicine. October 29, 2019. https://www.yalemedicine.org/conditions/strep-throat#:~:text=Caused%20by%20the%20group%20A,permanent%20damage%20to%20the%20heart.
  3. “The Differences between Flu, COVID, Strep Throat and RSV.” 2023. https://www.heart.org/en/health-topics/house-calls/differences-between-flu-covid-strep-throat-and-rsv.
  4. “Enhanced Immunity.” 2023. Centers for Disease Control and Prevention. September 5, 2023. https://www.cdc.gov/nccdphp/dnpao/features/enhance-immunity/index.html.

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