A sick woman in bed.

W ith COVID-19 still among us, even a slight cough or sore throat can be concerning, espe­cial­ly because older adults are at higher risk of complications from the coronavirus and infections such as the flu. But you might not always know whether you’re experiencing a garden-variety cold or something that requires more care.

“There’s an overlap between symptoms of COVID-19 and other respiratory illnesses, such as colds and flu, as well as even simple allergies,” says Heather Gantzer, MD, an internist at the Park Nicollet Clinic at Methodist Hospital in St. Louis Park, Minn. Because the best way to subdue symptoms—and know when to get medical counsel—can differ based on why you’re ill, it’s important to rule out potentially serious conditions, such as COVID-­19, she adds. The following can help.

Decode the Signs

While upper respiratory infections and allergies have plenty of snuffly symptoms in common, there are differences.

COVID-19: A loss of smell and/or feeling at least moderately short of breath may distinguish COVID-19 from other respiratory infections, says Ula Hwang, MD, a physician in Yale Medicine’s Depart­ment of Emergency Medicine in New Haven, Conn. In fact, a study published this past October in the journal PLOS Medicine found that ­almost 80 percent of people who ­reported a loss of smell or taste tested positive for COVID-­19 anti­bodies. COVID-19 also typically brings fever and, possibly, cough, diarrhea, nausea, and/or vomiting.

More on COVID-19

Flu: Unlike a cold, where symptoms start gradually, the flu tends to come on suddenly, Gantzer says. You’re also more likely to have a fever, chills, and head and body aches, and feel extremely exhausted, than you would with a cold or allergies. But as with a cold, you may have headaches, a cough, and/or a sore throat.

Cold: The common cold usually brings a runny, congested nose; a sore throat; and sometimes fatigue or a low-grade fever, Gantzer says. You might also notice a mild cough due to postnasal drip.

Allergies: If you’re sneezing and have itchy eyes, nose, or throat, allergies could be the cause—even in winter, says J. Allen Meadows, MD, immediate past president of the American College of Allergy, Asthma & Immunology. “In Southern states such as South Carolina, Georgia, Texas, and Alabama, we now see tree pollen as early as mid-January,” he says. Allergens such as dust mites, pet dander, and mold can cause more problems during the winter, when people spend more time indoors exposed to them, says Purvi Parikh, MD, an allergist and immunologist at NYU Langone Health in New York City.

Subdue Your Symptoms

If you think you may have COVID-19 or the flu, it’s important to contact your doctor right away for advice. Also:

COVID-19, flu, and colds: Isolate yourself, rest, and sip plenty of fluids, especially if you have a fever. “It’s a good idea for older adults to drink Pedia­lyte, which can help replace some of the electrolytes they will lose if they are sweating,” Gantzer says.

Acetaminophen (Tylenol and others), used according to package instructions, can help with aches and ­fever, but don’t take more than 3,000 mg a day, Gantzer says. Saline nasal spray can help relieve a stuffy nose and congestion. For a cough or sore throat, Gantzer recommends warm tea with honey or cough drops that contain pectin, which coats the throat.

If the cough is making you uncomfortable, consider using guaifenesin (in products such as Mucinex), which thins mucus so that you can cough it up more easily. To avoid taking more medication than you need, skip combination over-the-counter (OTC) cough and cold drugs and stick with those that have only one active ingredient.

COVID-19: In addition to the above, if you have mild to moderate COVID-19 and are at high risk for severe illness—a category that ­includes people 65 and older—you may be given a monoclonal antibody, such as bamlanivimab, shortly after diag­nosis. It may help stop the virus from enter­ing cells.

Flu: Ask your doctor about an anti­viral such as oseltamivir (Tamiflu and generic). Research shows that when given within 48 hours of the onset of symptoms, these lessen sick time by about 17 hours. This may, in turn, help prevent more serious flu complications, such as pneumonia, which are more common in older adults, says Nisha Rughwani, MD, associate professor of geriatrics and palliative medicine at the Icahn School of Medicine at Mount Sinai in New York City.

Allergies: If you’ve had allergies in the past and your symptoms are consistent with them, it’s reasonable to try an OTC steroid nasal spray, such as fluticasone (Flonase and generic), and a saline nasal rinse. (But if symptoms persist, let your doctor know.) Also, steer clear of exposure to aller­gens, if possible. For instance, to avoid dust mites, encase your mattress, box spring, and pillows in allergen-­proof covers, and wash bedding weekly in ­water that’s hotter than 120° F.

Know When to Get More Help

Because the risk of severe complications from the flu or COVID-19 increases with age, contact your doctor during your illness if you experience significant shortness of breath and/or a home pulse oximeter measures an oxygen level of 95 percent or lower. Also alert the doctor if you have dehydration signs, such as very dark urine, or if your fever or cough improves, then returns.

Call 911 right away if you have persistent chest pain or pressure, bluish lips, or sudden feelings of weakness. “Unfor­tun­ately, sometimes the first sign of COVID-19 in older adults is a heart attack or a stroke,” Gantzer says.

And if you have any questions or concerns, this winter it’s better to err on the side of caution and call your doctor or even head to the emergency room, Rughwani says. “This year, the stakes are too high to watch and wait, especially for older adults,” she says. 

Testing Tips

Older adults who suspect a respiratory infection should tell their doctors. “It’s a good idea to get a COVID-19 test, even if your symptoms are mild, because if you do have COVID-19, you’ll know to self-isolate for 10 days,” says Heather Gantzer, MD, of Methodist Hospital in St. Louis Park, Minn. “And if you do have COVID-19, it gives you a heads-up to be on the lookout for more potentially serious health complications, such as low oxygen levels, that you might need to be hospitalized for.”

Ask whether you should be tested for the flu, too: Both infections are contagious and can be serious, especially for older adults. Getting tested, especially for COVID-19, also helps health experts keep track of local community spread, says Nisha Rughwani, MD, of Mount Sinai in New York City. While waiting for test results, assume that you’re positive and stay in a room separate from other household members as much as possible; wear a mask if you can’t do that.

Use a separate bathroom, if there is one, and avoid sharing items such as cups, towels, and utensils. Clean and disinfect high-touch surfaces in your “sick room” and bathroom every day. (A caregiver can also do this while wearing a mask and disposable gloves.) 

Editor’s Note: A version of this article also appeared in the February 2021 issue of Consumer Reports On Health