Allergies? Common cold? Flu? Or COVID-19?

With so many of us wrestling with fears and unknowns surrounding the coronavirus pandemic, every throat tickle, nose drip, or cough is suspect: do I have coronavirus? By now, we all know that COVID-19, the illness caused by coronavirus, can cause severe, life-threatening symptoms, although the majority of people who have it will experience a mild to moderate version.

Of course, it is spring, so many people may be experiencing their annual springtime tree pollen allergies. Colds also remain common, just as was true before the coronavirus. And although influenza season is coming to an end, perhaps you’ve wondered if some of your symptoms could be the flu. Below, I’ve explained key symptoms to help you distinguish these illnesses and take action as needed.

Are your symptoms consistent with COVID-19?

At the beginning of the pandemic, your travel history offered important clues, but this is no longer pertinent because coronavirus has been spreading in our communities.

Keep in mind that most people who get COVID-19 will be able to recover at home (see information about what to do if you are sick from the Centers for Disease Control and Prevention). However, if your symptoms are worrisome or severe, call your doctor or local hospital, or check with your local health department so you can be evaluated immediately, if that’s necessary.

Key symptoms: The more common and sometimes severe symptoms of COVID-19 are fever, cough, and shortness of breath. Two additional common symptoms are fatigue and loss of appetite. Less commonly, people may have diarrhea, nausea, or vomiting. Some people report a lack of taste or smell. A significant number of people experience no symptoms (it’s even possible to have coronavirus and not experience a fever).

Usually symptoms appear within five days after exposure, but it can take up to 14 days.

How can I be certain I have COVID-19? If you are concerned about symptoms, contact your doctor or your local board of health to find out whether you should be tested, and if testing is available near you. The criteria for getting tested are rapidly changing as more tests become available.

Are your symptoms consistent with allergies?

Spring, with its budding trees and warmer weather, means allergy season for many of us. As you see the trees in your area budding, that means the pollen counts will also be increasing.

Key symptoms: Two strong indicators that suggest allergies: if you’ve had springtime allergies before, and if itch is a prominent component of your symptoms. People with allergies often have itchy eyes, itchy nose, and sneezing, as well as less-specific allergy symptoms such as a runny, congested nose, and a sore throat or cough that is generally due to postnasal drip.

How can I be certain I have allergies? The best way to diagnose allergies is by using skin testing at an allergist’s office. If you found taking medications such as over-the-counter antihistamines or steroid nasal sprays helpful in prior years, then it would be reassuring that if your symptoms improve with these medications, your symptoms may be due to seasonal allergies. As anyone with allergies can attest, allergies linger for months, so the timeline can often be a clue, too.

Are your symptoms consistent with the common cold?

In medicine we often say “common things are common,” and the common cold remains common even during this pandemic.

Key symptoms: Symptoms of the common cold are usually a runny, congested nose as well as a sore throat, headache, and generally feeling unwell. A mild cough due to postnasal drip and sneezing can occur, but itch would be less likely. More severe symptoms, such as fever and shortness of breath, are not classic symptoms of the common cold.

How can I be certain I have a cold? A cold is usually diagnosed simply by assessing symptoms and without testing. Over-the-counter cold medications often can help with symptom control. The common cold will usually resolve within approximately one week of onset of symptoms.

Are your symptoms consistent with the flu?

In the US, the flu season is coming to an end, whereas COVID-19 numbers continue to rise. So, flulike symptoms should prompt concern for COVID-19.

Key symptoms: Flu is characterized by fever, chills, muscle aches, and exhaustion. It classically comes on suddenly, as opposed to the more gradual onset of the common cold. More mild symptoms can also occur, similar to the common cold, such as a runny nose, sore throat, and headache. Vomiting and diarrhea are uncommon in adults, but can happen in children.

How can I be certain I have the flu? Flu is diagnosed based on a swab test performed by a healthcare provider. Prescription medications can limit the duration of influenza symptoms, but need to be started promptly. The flu vaccine is also an important part of prevention. The duration of symptoms is approximately one week, with symptom improvement occurring around five days.

Still not sure what is causing your symptoms?

You may find this chart from the American Academy of Allergy, Asthma & Immunology helpful. However, it’s wisest to check with your doctor if you’re concerned that your symptoms might be due to COVID-19.

For more information about coronavirus or COVID-19, see the Harvard Health Coronavirus Resource Center and podcasts.

Related Information: Controlling Your Allergies


  1. Dana Lambert

    In 2018 I had pulmonary edema with sepsis secondary pneumonia, since then I now have autoimmune diseases (3). This last March I was admitted to hospital due to an infection in my small intestines. Now I’m suffering with allergies, fatigue, exhaustion and ear issues. Seems very strange!!!!

  2. Nader

    It would be nice to have a chart that showed the symptoms of each of the three next to each other. The reader wouldn’t have to jump back and forth to find out the severity of any common symptom in each case.

  3. Jack-RI

    Is there any reason to believe that people with HIV who are on the retroviral cocktail would have ANY amount of immunity to the virus?

  4. Janet Pearce

    Lovely for you to be experiencing the end of winter and all the beautiful spring blossoms and flowers and warmer temperatures even if it means allergies.
    Thank you for your comments, they are very helpful- if you are lucky enough to be experiencing spring. I would like to point out that parts of the world do not have the pleasure of spring right now.
    Here in Australia and New Zealand, we have opposite seasons to you because we live in the Southern Hemisphere. We are now entering the wonderful season of Autumn, or Fall, as people in the US call it, and yes, some trees are turning beautiful colours, ready to drop their leaves. It too is a beautiful season.
    So, in most parts of Aus and NZ, during the months ahead we will cope with coughs, colds, runny noses, fevers, aches and pains which usually accompany winter ills.
    Please spare us a thought as we enter the colder months of the year. We do not know how this dreadful virus which is crippling so many aspects of our lives will behave in winter, or if the signs of the virus will be mistaken for the flu. We have that ahead of us.

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