Do I Have a Cold or the Flu?

You have a runny nose, a cough, a fever, and a pounding headache, but what’s making you feel so awful? Figuring out whether you’re dealing with the common cold or the flu is often hard to tell.

Finding the Cause Depends on the Type of Virus

Both a cold and the flu, or influenza, are respiratory infections, but they’re caused by different viruses. A cold can be caused by any one of more than 200 distinct viruses, while there are only a handful of viruses that cause the flu, notes the Centers for Disease Control and Prevention (CDC).

As a general rule, the flu is usually more intense and fierce than the common cold. In some situations, it can be important to know if you have the flu, since it is more likely to lead to serious complications, including pneumonia, bacterial infection, or hospitalization. Watch out for a fever that goes away and then comes back, since that can be a sign of a secondary bacterial infection, cautions Charles Foster, MD, of the Cleveland Clinic’s Center for Pediatric Infectious Diseases in Ohio.

Spotting the Difference in Symptoms and Onset of Illness

Key Symptoms of a Cold

Fever, runny nose, fatigue, headache, and muscle aches are symptoms shared by both cold and flu. It can be difficult to identify if you have a cold or flu because these symptoms overlap.

It may be helpful to remember that a runny, stuffy nose is a common indicator of a cold, along with scratchy throat, sneezing, watery eyes, and a mild fever (below 102 F, and fever with a cold is more common in younger children), according to the Cleveland Clinic. In some instances, allergies like hay fever (allergic rhinitis) can have many similarities to the cold, but without fever and muscle aches.

Key Symptoms of the Flu

Symptoms that indicate flu tend to be more severe than with a cold and include high fever (above 102 F), nausea, cough without phlegm, chills, body aches, sweating, and lack of appetite, per the Cleveland Clinic.

Difference Between the Onset of Cold vs. Flu Symptoms

In addition to examining your symptoms, watching how they develop can give you a clue as to which illness you have. Cold symptoms tend to develop gradually, while flu symptoms can come on suddenly, without warning.

Learn More About Cold and Flu Symptoms

Seeking Medical Care to Determine if You Have a Cold or the Flu

Your doctor can perform tests in the first few days after you develop symptoms to determine whether you have a cold or the flu. However, you usually don’t need to visit the doctor unless your symptoms are severe, you have a preexisting health problem that puts you at high risk of a complication, or your symptoms indicate a more serious infection.

Whether you have a cold or the flu, expect your symptoms to stick around for about 10 days. There is no cure for a cold, but in some severe cases of the flu, your doctor may recommend an antiviral medication to speed up your recovery time. Antiviral drugs are considered a second line of defense after flu vaccinations. While it is still possible to get the flu if you get the vaccine, research has shown that, barring full prevention, the flu shot does also reduce the seriousness and duration of the virus, according to the CDC.

Since both the common cold and the flu are caused by viruses, not bacteria, antibiotic medicines are not of any use in combating them. But as the Cleveland Clinic’s Dr. Foster noted above, if your symptoms linger or seem to go away and then return, check with your doctor to ensure you don’t have a secondary bacterial infection, which would be treated with antibiotics.

Get plenty of rest, avoid smoking and alcohol, drink plenty of water and juice, and take over-the-counter medication to treat specific symptoms and help you feel better as your body fights off the infection.

Learn More About Cold and Flu Treatment