Your Day-by-Day Guide to the Common Cold

“Although you can have a cold start with a number of different symptoms, the most common first symptoms are congestion, runny nose, and sore throat, signs that the virus is directly affecting your respiratory system,” says Nate Favini, MD, an internist and the medical director of the nationwide healthcare system Forward, who is based in San Francisco.

In this first stage of a cold, it’s especially important to rest as much as possible to minimize fatigue and keep your immune system at full power.

During the next stage of a cold, nasal symptoms continue to develop, peaking during the third and fourth days. You may notice that mucus from your runny nose has become thicker, with a yellow or green tinge. This usually is due to a spike in the number of white blood cells your immune system has dispatched to overcome the virus, according to the Mayo Clinic. As you get better over the next few days, the discharge tends to clear up. In the meantime, however, a cough may develop in response to postnasal drip, says Dr. Favini.

People often assume that the discolored mucus is a sign of a bacterial infection, and so antibiotics are what they need — but this is a common misconception, the Mayo Clinic notes. The discolored mucus is actually a normal part of the course of the common cold, which is a viral infection and will not respond to antibiotics.

The average duration of a cold is 7 to 10 days, and most people recover without any specific treatment. But cold symptoms may last longer or become more severe in people who have immune problems or other underlying health issues, such as diabetes, says Soma Mandal, MD, an internist with Summit Health in New Providence, New Jersey. If you have a medical condition that puts you at increased risk for complications, reach out to your healthcare provider.

Be aware that it may take up to six weeks for a cough to disappear even after other symptoms fade, Dr. Mandal says. Usually, this is due to postnasal drip, which can continue to form while swollen and irritated nasal passages heal, she explains.

If you’ve been nursing a cold but haven’t gotten better after a week, if cold symptoms return often, or if you had started to feel better only to have symptoms then worsen again, you may be dealing with allergies or a sinus infection rather than a cold.

Symptoms commonly associated with allergies, which can last months, include:

• Itchy or watery eyes
• Clear runny nose
• Nasal congestion
• Sneezing
• Postnasal drip
• Dry cough

Symptoms of a sinus infection, which can last anywhere from one to three months or more, can include:

• Nasal congestion
• Sore throat
• Pressure or pain around the eyes and forehead
• Fatigue
• Fever
• Tooth or jaw pain when chewing (especially of the upper jaw)
• Persistent nasal discharge

If you suspect allergies or a sinus infection, Dr. Glatt recommends seeing your doctor to get a complete evaluation.

It can be difficult to tell these illnesses apart because they share so many traits. What’s more, because they are caused by different germs that affect the respiratory system, it’s possible — although rare — for them to overlap. In other words, you could have more than one ailment at the same time, according to the CDC.

In general, CDC experts say, flu symptoms tend to come on suddenly rather than build up gradually as they do with the common cold. Flu symptoms are also more intense and last longer.

Symptoms of COVID-19 also tend to develop a bit more gradually and can include ones not typically seen with a cold or the flu, such as diarrhea and a new loss of taste or smell, according to the CDC.

As always, call your medical provider if any symptoms become severe or concerning to you. Be especially aware of the emergency warning signs for COVID-19. Someone showing any of the following signs should seek emergency medical care immediately:

• Trouble breathing
• Persistent pain or pressure in the chest
• New confusion
• Inability to wake up or stay awake
• Bluish lips or face

Additional reporting by Nuna Alberts.