Coronavirus, Flu, Cold or Allergies? Know the Symptoms

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Young Hispanic man sick in bed with cough due to cold, flu or bronchitis

Most people know the symptoms of the common cold, but what about seasonal flu (influenza) and the novel coronavirus disease (COVID-19)? The COVID-19 Symptom Comparison Chart can help you figure out whether it's a cold, flu or COVID-19. But now that spring is here, is your runny nose the beginning of an infection or is it allergies? Some symptoms overlap between all three viral illnesses and spring allergies, so it’s important to know the differences.

Coronavirus Symptoms

Without a lab test, the novel coronavirus disease is difficult to diagnose because COVID-19 symptoms are not specific to coronaviruses and other respiratory infections. Coronavirus symptoms tend to come on gradually, over several days.

The eight most common COVID-19 symptoms, in order, are:

  • Fever (usually above 100.4°F and higher)

  • Dry cough

  • Fatigue

  • Sputum (phlegm) production

  • Shortness of breath

  • Sore throat

  • Headache

  • Body aches

Runny nose and sinus congestion are very uncommon in COVID-19. Also, less than 10% of infected individuals experienced nausea, vomiting, diarrhea, or stuffy nose according to a joint report by the World Health Organization and China based on 55,924 COVID-19 patients.

Symptoms of mild COVID-19 cases last 3 to 7 days, but it can take a couple of weeks for symptoms to subside. With severe COVID-19 cases, it may take several weeks or longer to recover.

Flu Symptoms

Symptoms of flu come on suddenly and include:

  • Fever (usually above 100.4°F and higher)

  • Cough

  • Fatigue

  • Sore throat

  • Stuffy and/or runny nose

  • Body aches

  • Headache

  • Vomiting or diarrhea in some cases (more often in children than adults)

Cleveland Clinic created a mnemonic, F.A.C.T.S. to remember flu symptoms: Fever, Aches, Chills, Tiredness, Sudden onset.

Frequent symptoms common to coronavirus and flu are fever, cough and fatigue. The distinction is coronavirus tends to cause shortness of breath and produces phlegm (from the respiratory system), but influenza does not unless pneumonia develops.

Flu symptoms last 5 to 7 days, which is slightly shorter than cold symptom duration.

Cold Symptoms

Like coronavirus symptoms, cold virus symptoms come on gradually, but the symptom set is different.

Common cold symptoms include:

  • Stuffy nose

  • Sneezing

  • Sore throat

  • Cough and/or mild chest congestion

Some people develop fatigue and body aches, but those symptoms are not as frequent as they are with flu. It is rare to have fever, chills or headache with a cold. However, if there is fever related to common cold, it is below 100.4°F. Most people can function fairly well with a cold, but not with the flu.

The common cold lasts 7 to 10 days; if present, cough can last longer.

Allergy Symptoms

Allergy symptoms come on gradually during allergy season, but they may flare up suddenly on high pollen days.

Seasonal allergy (hay fever) symptoms include:

  • Stuffy nose

  • Runny nose

  • Sneezing

  • Itchy eyes, nose, throat, even the ears

  • Eye redness, discharge and swelling

  • Mucus draining from the nose and sinuses, which is different from phlegm or sputum from the lower respiratory tract

  • Cough and wheezing, if the allergy causes asthma

  • Headache (from sinus congestion, not fever)

Your symptoms are most likely due to allergies if you tend to develop these symptoms at the same time every year and your first symptoms involve your eyes and nose. Seasonal allergies do not cause a fever or body aches, but you may feel tired.

Although allergy symptoms may continue for days, they don’t get worse with time; whereas, viral respiratory infections get worse within a short period of time. Over-the-counter allergy medicines usually clear up symptoms.

When in doubt, contact your doctor for a symptom evaluation, especially if you have difficulty breathing or chest pain. Simply communicating your symptoms to a healthcare professional can reassure you that you do not have coronavirus and point you in the right direction to reveal the cause of your symptoms.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Mar 19
  1. Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19). World Health Organization.
  2. Is It a Cold or the Flu? Know Your ‘F.A.C.T.S.’ Cleveland Clinic.
  3. Cold Versus Flu. Centers for Disease Control and Prevention. 
  4. Flu Symptoms & Complications. Centers for Disease Control and Prevention.
  5. Coronavirus.
  6. Sorting out symptoms of COVID-19, influenza, colds and allergies. Cedars Sinai.

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