Differentiating Allergies, the Flu, and COVID-19

It can be difficult to tell the difference between COVID-19, the flu, and seasonal allergies. They have many similarities when it comes to symptoms, and that just further complicates the process.

Common symptoms shared between the three include a sore or itchy throat, runny nose, and sneezing. This can make it harder to differentiate if those are the only symptoms, though the appearance of new symptoms can help to narrow it down.

Common Symptoms for Both COVID-19 and the Flu (influenza)

To make matters more complex, COVID-19 and the flu share many more symptoms than they do with allergies. Symptoms include fever, body aches, fatigue, shortness of breath, runny nose, cough, sore throat, headaches, and sometimes vomiting, and diarrhea.

Both illnesses spread in similar ways and can be contagious even when a person is asymptomatic. In many cases, the onset of symptoms tends to be rapid, within four to ten days from exposure.

Seasonal Allergy Symptoms

Common symptoms for seasonal allergies include sneezing, runny noses, watery or itchy eyes (sometimes pink or red), itchy sinuses, itchy throat, ear congestion, and postnasal drip (with consequent clearing of your throat). Less common symptoms include headaches, shortness of breath, wheezing, and coughing.

When comparing the less common symptoms side by side with the flu and COVID-19, it’s easy to see how confusion may arise. One of the quickest ways to spot an allergy is to identify its pattern. Is it coming back at the same time every year? Do the symptoms recur in similar places (eg: a child’s bedroom with a lot of soft toys)? If so, the allergies are likely to be the cause.

Telling the Difference

Several key symptoms help to distinguish COVID-19 from the flu or allergies. Patients with COVID-19 have been known to report a loss of taste and smell. This is unlikely for either the flu or allergies.

The symptoms for COVID-19 may linger longer than those of the flu. This is especially true for patients with preexisting conditions. Additionally, occasionally younger patients have reported the appearance of a rash on their toes, something that the flu is not known for.

When suffering from various symptoms and trying to understand which condition is the cause, it’s time to take a closer look. Seasonal allergies can make a person feel tired and run down, but the symptoms are unlikely to spike or get worse. Both COVID-19 and the flu will cause a rapid onset of symptoms, though COVID-19’s symptoms are more iconic and may last longer.


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