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Published on August 25, 2020

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Flu, COVID-19 or Allergies: What’s the Difference?

Influenza, allergies and COVID-19 all share some symptoms, and that can make it difficult to know what’s causing your discomfort. All three may come on in similar ways, but they’re definitely not the same.

It can help you and your family to understand the signs that the flu, COVID-19 and allergies share, as well as how they differ.

Allergies don’t affect everyone – learn more about how flu and COVID-19 are alike.

The Similarities

Influenza, COVID-19 and allergies can all cause:

  • Cough
  • Congestion
  • Runny nose
  • Headaches

Both influenza and COVID-19 can:

  • Cause fever or chills, cough, congestion or runny nose, body aches, headaches, fatigue, and sometimes nausea, vomiting and diarrhea.
  • Be mild or severe, but rarely fatal.
  • Result in pneumonia.
  • Be spread from person to person through coughing, sneezing or talking, and both can be spread before symptoms appear.

The Centers for Disease Control and Prevention (CDC) said it’s possible to test positive for flu – as well as other respiratory infections – and COVID-19 at the same time. Some additional symptoms of COVID-19 that you may not experience with influenza or allergies include:

  • Difficulty breathing – although allergies may cause shortness of breath
  • New loss of taste or smell

Additionally, allergies can cause watery or itchy eyes, ear congestion, postnasal drainage and sneezing, symptoms that are not common to either influenza or COVID-19.

How They Differ

While all three illnesses share some similar symptoms, the differences lie in the cause, transmission and treatments.


  • The flu can be caused by a number of different strains of influenza viruses.
  • COVID-19 is caused by one virus, the novel 2019 coronavirus.
  • Allergies occur when the body reacts to foreign substances – pollen, dust, mold, insect stings and pet dander, among many other substances – that doesn’t cause a reaction in most people.


  • The flu and COVID-19 can both be spread when an infected person coughs, sneezes or talks.
  • COVID-19 might also be spread through the air when tiny droplets hang in the air even after the infected person leaves the room.

Allergies can be genetic or something a person is born with. Adults usually don’t lose their allergies, but some children outgrow them. They cannot be passed from person to person like influenza or COVID-19.


  • Antiviral medications, such as Tamiflu, can address some flu symptoms and possibly shorten its duration.
  • Testing continues on effective treatments for COVID-19 to see if they can address the symptoms.

The simplest treatment for allergies is to avoid known allergens, but if that’s not possible, there are also medications that may help. See your doctor for more information, or make an appointment with one of Avera’s allergy specialists.


  • A flu shot can prevent some of the more dangerous types of flu, or reduce the severity if it’s contracted.
  • The COVID-19 vaccine can help you avoid the worst of the coronavirus. It's available to everyone 5 and older.
  • Allergy shots – also known as immunotherapy – can reduce allergy attacks, but there is no allergy vaccine.


The flu and COVID-19 may be prevented by frequent, thorough hand washing, coughing into your elbow, staying home when sick and limiting contact with infected people. Allergies cannot be prevented, but avoiding allergens and taking medication as prescribed can help.

Learn more about COVID-19 at

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