9 Signs It's More Serious Than the Common Cold

The common cold tends to clear up on its own in three to four days, says Melisa Lai Becker, MD, site chief of emergency medicine at Cambridge Health Alliance. It starts with a scratchy throat, congestion, and runny nose, and then a cough usually develops. While your cough and post-nasal drip may linger, most head cold symptoms should disappear after four days.

"With a cold, you ultimately feel OK after a couple days of rest, hydration, and Kleenex," she says.

If symptoms last for longer, it’s possible you have something more worrisome, such as the flu or mononucleosis.To be safe, make an appointment with your physician.

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Recent international travel is a red flag for doctors because it could mean you have a less-conventional infection they wouldn’t have normally considered, explains Stella Safo, MD, an internist at Mount Sinai Hospital who specializes in infectious diseases. It’s important to see a doctor if you have any symptoms after returning from a trip abroad.

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The question of "Can you have a fever with a cold?" is a tricky one. While it's definitely possible to be feverish when you have a cold, it's not common—especially high fevers.

If you have a fever at or above 101 degrees Fahrenheit, it could be a sign of strep throat, says Dr. Lai Becker. Most patients with strep will develop a high fever in the first few days of illness, so be wary of sudden spikes in your temperature. "Strep throat is one thing you really want to distinguish from a cold," she says. "Left untreated, it can cause rheumatic fever and lead to serious heart problems."

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Even if your fever isn’t particularly high, running a low-grade fever for several days in a row could be a sign your body is trying to fight off more than a cold, says Dr. Lai Becker. A consistent fever could mean you actually have the flu or mono—so be diligent about checking it, even if it doesn’t feel super intense.

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Having nausea with a cold—as well as vomiting and diarrhea—isn't typical, so symptoms like these could signal something more serious, such as the flu. It’s important to get medical attention if you’re experiencing these symptoms consistently, as they can cause you to become dehydrated, says Dr. Mysore.

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Even though a cough is a normal symptom of a cold, it shouldn’t be so severe that it causes shortness of breath, wheezing, or chest pain, says Dr. Mysore. These symptoms shouldn’t be ignored, since breathing trouble could be a sign of bronchitis or pneumonia, while chest pain, tightness, and sudden shortness of breath could signal a pulmonary embolism (a blood clot blockage in the lungs).

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Another red flag it’s more than a cold is a “localization” of symptoms, meaning you feel them in one specific area, explains Dr. Safo. While cold symptoms affect the whole upper respiratory system, other illnesses are characterized by intense symptoms in one place. For example, Dr. Lai Becker points out that strep causes a sore throat so bad it’s difficult to swallow, but typically won’t cause pain throughout the body. Sinus infections can cause headaches and even make your teeth hurt, an ear infection will usually cause pain and congestion in one ear, and mono can cause swollen tonsils.

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A regular cold is no walk in the park, but it shouldn’t cause all-over body aches and pains. On the other hand, the flu can make your muscles and body feel achy, and can also be accompanied by fatigue and chills.

"With the flu, you’ll feel like you got hit by a truck," says Dr. Mysore. Just getting out of bed will wear you out, and your muscles will be tender and sore.

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It can be hard to distinguish allergies from a cold, since they have similar symptoms. But allergies will often follow a pattern, says Dr. Lai Becker. If you notice your symptoms are worse after spending time outside or with a pet, or they tend to come and go with a certain season, you likely have allergies. “I had one patient who thought he was sick, but the real story was that he was allergic to a cat,” Dr. Lai Becker says.

To pinpoint the exact cause, keep track of your symptom history and see if you notice any trends; it could mean you’re allergic to something or have seasonal allergies.

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