Is it a cold, the flu, allergies or COVID-19?

Last updated September 24, 2021

Self-diagnosis has never been an exact science. But with the coronavirus (COVID-19) now added to the mix, figuring out what those sniffles, that cough, or those itchy eyes really mean has never been more challenging.

For help determining what might be causing your upper respiratory symptoms, when to seek medical attention, and how to protect yourself from colds, the flu and the coronavirus, we spoke with our infectious diseases and infection control specialist Roy Chemaly, M.D. Here’s what he had to say.

How can people figure out if they have a cold, the flu, allergies or COVID-19?

It’s very hard to differentiate between a cold, the flu, allergies and COVID-19. All four have overlapping symptoms, such as runny nose, congestion, chills and fatigue.

Is there any symptom that’s exclusive to each condition, so that someone can definitely say whether it's a cold, flu, allergies or COVID-19?

No. Allergies are the only thing you may be able to rule out if you have a fever. Allergies do not cause a rise in body temperature, but an additional infection (such as a sinus infection or strep throat) can.

Even with symptoms such as itchy eyes, congestion, a runny nose or conjunctivitis, it’s very hard to rule out COVID-19. Because while those things are more commonly associated with allergies, colds, or the flu, they can also be symptoms of the coronavirus.

You can’t base a diagnosis on how quickly you start to feel bad, either. Sometimes, COVID-19 symptoms start out slowly and build up very gradually, but people have also reported a rapid onset of symptoms, which is very similar to the typical flu. So, getting tested for COVID-19 and the flu really is the only way to go.

When should someone seek medical care, and when is it OK to try to recover at home?

If you are a cancer patient and you have a fever higher than 100.3 F, you need to seek medical care immediately. At MD Anderson, we will automatically test you for COVID-19 on admission, as well as 21 other pathogens, and isolate you until we can determine what’s causing your fever.

If you don’t have cancer and are healthy, you should see at least a slight improvement in how you feel with every day that goes by, regardless of what’s causing your symptoms. Stay at home and isolate yourself until your symptoms go away.

But if you’re not getting better — or you’re actively getting worse —you need to seek help. This is especially true if you start experiencing some of the more concerning COVID-19 symptoms, such as shortness of breath, a severe cough, or breathing problems.