What's the difference between COVID, cold, flu and allergies?

Note: This article was last updated in September 2020. For the latest updates on COVID-19, see Piedmont.org.

Each fall, we see an increase in the flu, common cold and, early in the season, allergies. This year, we are also dealing with the COVID-19 pandemic. How do you know if you have a cold, allergies, the flu or COVID-19? Lauren Powell, M.D., a Piedmont primary care physician, highlights key differences, prevention tips and when to seek care.

How to tell the difference between COVID-19 and the flu

“It’s pretty difficult to tell the difference between the flu and COVID-19 based on symptoms alone. Both are viral illnesses and can present in the same way in terms of respiratory symptoms, fever and aches,” says Dr. Powell. “The best way to determine if you have the flu or COVID-19 is through testing.”

Symptoms caused by the flu

Flu symptoms: Flu symptoms include fever, chills, cough, shortness of breath, fatigue, congestion or runny nose, sore throat, muscle aches, and headache. Some people experience diarrhea or vomiting, though this is more common in children than in adults.

How to know if you have the flu: To know for sure if you have the flu, you need to get tested. Call your primary care provider’s office or book a virtual visit to see if you qualify for testing.

Symptoms caused by COVID-19

COVID-19 and the flu share the following symptoms: Common symptoms include fever, chills, cough, shortness of breath, fatigue, congestion or runny nose, sore throat, muscle aches, and headache. Some people experience diarrhea or vomiting, though this is more common in children than adults.

What’s different about COVID-19: Dr. Powell notes that COVID-19 symptoms can range from none to mild cold- or flu-like signs to severe illness requiring hospitalization. Some people with COVID-19 experience a loss of or change in sense of taste or smell. Additionally, COVID-19 appears to spread more easily than the flu and currently has a higher mortality rate.

How to know if you have COVID-19: To know for sure if you have COVID-19, you need to get tested. Call your primary care provider’s office or book a virtual visit to see if you qualify for testing.

Symptoms caused by allergies

Allergy symptoms: You may have allergies if you’ve experienced them before and notice symptoms like itchy eyes, a runny or itchy nose, or sneezing. Coughing due to postnasal drip, a sore throat and a runny, stuffy nose are also common with allergies.

How to know if you have allergies: Allergy symptoms may also stick around for several weeks or months. If over-the-counter allergy medications have helped your symptoms in the past—and do so again this year—it’s likely you’re dealing with allergies. To know for sure if you are experiencing seasonal allergies, you can undergo skin allergy testing at an allergist’s office. 

Dr. Powell also notes that allergy season should conclude before flu season ramps up.

Symptoms caused by the common cold

Common cold symptoms: Cold symptoms include a runny or stuffy nose, headache, sore throat, and a general feeling of being unwell. A cold can sometimes cause a cough due to postnasal drip or sneezing, but without the itchiness associated with allergies. Cold symptoms typically don’t include shortness of breath or fever.

How to know if you have a cold: No testing is required; most healthcare providers assess based on symptoms.

How will COVID-19 affect the 2020-2021 flu season?

Precautions against COVID-19 may also help reduce the spread of flu and the common cold, Dr. Powell says.

“Many of us are working from home, kids are not in school and we have less contact with other people, which helps minimize the spread of the common cold, flu and COVID-19,” says Dr. Powell. “People are also more health-conscious at this point. I had patients requesting the flu shot in August, even though it was too early to begin vaccinating. I’ve never had patients request it that early. In general, people are very conscious of their health and want to do whatever they can to stay healthy.”

What to do if you have flu or COVID-19 symptoms

If you have symptoms of COVID-19 or flu, contact your doctor or book a virtual visit as soon as possible. Testing is essential to ensure you get the right treatment and take the correct steps to prevent spreading the illness. Researchers believe COVID-19 is contagious for longer than the flu.

Can you get COVID-19 and the flu at the same time?

Dr. Powell says it’s possible to get both the flu and COVID-19 this season since they are two different viruses. While it’s rare, people can become infected with both viruses at the same time.

How to prevent illness

Dr. Powell recommends the following steps to reduce your risk of illness and avoid spreading illness to others:

• Wash hands often with soap and water for at least 20 seconds, or use sanitizer with at least 60% alcohol.
• Wear a mask in public. A mask should cover both your nose and mouth.
• Watch your distance. Keep at least six feet between you and people not in your household.
• Get a flu shot. A flu shot is more important than ever. While the vaccine isn’t 100% effective, it has been proven to reduce cases of the flu and if you do still contract the flu virus, you’ll likely have milder symptoms and a lower risk of hospitalization and death. Widespread flu vaccinations can also help reduce the load on our nation’s healthcare system.
• Clean and sanitize high-touch surfaces in your home, like doorknobs, countertops and smartphones.
• Nourish your body by eating healthy foods.
• Exercise regularly.
• Get at least seven hours of sleep each night.
• Manage your stress levels.
• Take a daily multivitamin.

“Be diligent about taking all safety precautions,” says Dr. Powell. “If you have symptoms, self-isolate, avoid contact with other people and contact your doctor for testing. It’s important to be responsible for your health and the health of the people around you.” 

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