Ways to Distinguish Between a Cold, Flu and Pneumonia


If you’re sneezing or have a hacking cough, as well as some other symptoms, you might pass it off as a simple cold. But is it? When it comes to the flu or pneumonia, early treatment is key so ignoring certain signs can lead to bigger problems that can’t be cured from over-the-counter medication.

While colds, flu and pneumonia share some similarities, there are differences in the symptoms – are more accurately, the severity of the symptoms. Let’s take a look at 12 ways these 3-ailments are different from one another…

Feeling Out a Cold

LiveStrong defines colds as illnesses caused by viruses that affect the upper respiratory tract – namely the throat, nose, sinuses and ears. Colds are also referred to as upper respiratory infections or URIs, adds the source.

It explains there are actually more than 200-different cold viruses, with rhinovirus being the most common. While adults present the usual runny nose and sneezing, infants can develop a fever or ear infections from a simple cold, making it hard to distinguish from other ailments.

What’s a Flu Then?

The same source says a flu is typically more severe, and can affect the lower respiratory tract (lungs) as well as the other places a cold targets. Flu is caused specifically by one of the Influenza viruses, and often involves fever.

However, a flu will feel worse than a cold, and hit children especially hard – so keep an eye on symptoms such as high fevers, body aches, and fatigue.

Pneumonia No Minor Matter

This is actually an infection of one or both lungs, and is caused by bacteria (the most common cause in adults), a virus, or fungi, explains Healthline.

This type of illness causes the air sacs in your lungs (called alveoli) to become filled with fluid, which leads to difficulty breathing. Pneumonia can be very serious, and those under 2-years and older than 65-years are in a higher risk category, adds the source.

A Virus Can Be The Culprit For All Three

Viruses are responsible for the common cold and influenza (flu), and as we mentioned earlier, there are many strains of viruses that can cause colds while the flu can be traced to a couple of them (and their subtypes).

While pneumonia can certainly be attributed to a virus, it can also be caused by a bacterial infection or fungi. “Viral pneumonia is usually not serious and lasts for a shorter time than bacterial pneumonia,” notes Healthline.

By The Symptoms: A Cold

If we don’t look at the underlying cause (viral or bacteria), we can make some distinctions between colds, flu and pneumonia by the type of symptoms they present.

The Mayo Clinic lists a number of possible symptoms of the common cold, including a runny/stuffy nose, sore throat, cough, congestion, mild headache or body aches, sneezing (of course), low-grade fever, and a general feeling of being unwell.

By The Symptoms: A Flu

The Centers for Disease Control and Prevention (CDC) lists more severe signs when you’re dealing with influenza. For example, you might be experiencing a fever and chills (but not in all cases), sore throat, muscle and body aches, fatigue, and less commonly vomiting or diarrhea.

Those symptoms coincide with some cold symptoms, such as a cough or runny/stuffy nose, adds the source. Interestingly, sneezing doesn’t make the list from the CDC as a telltale sign of flu.

By The Symptoms: Pneumonia

If you have pneumonia, the symptoms are almost guaranteed to be more alarming. The Mayo Clinic says if you’re dealing with this ailment, you can experience chest pain when you breathe or cough, along with shortness of breath, fever, chills, and nausea.

You may also have phlegm with a cough and fatigue. In older patients (over 65), there can be confusion and lowered mental awareness associated with the ailment. Seniors may also experience lower than normal body temperatures, adds the source. For those of advanced age or others with pre-existing heart or lung problems, pneumonia can be life threatening.

They Move at Different Paces

The CDC explains that the onset of symptoms can be a clue to what illness you’re dealing with. It notes that flu symptoms are abrupt – meaning that you can feel fine one day and not the next. Meanwhile, cold symptoms tend to come on more gradually, it adds.

Meanwhile, depending on the underlying cause of pneumonia, it can come on at different speeds. “Symptoms of pneumonia caused by bacteria in otherwise healthy people younger than 65 usually come on suddenly,” offers WebMD. Other types (nonbacterial) can appear gradually, it adds.

Lifespan of Colds, Flu, and Pneumonia

KidsHealth.org explains that although colds “can linger for as long as 2 weeks, most clear up within a week” – although patients can be contagious for up to 3-weeks, it adds.

Sources note that most flu cases last around the same amount of time as a cold, while pneumonia – the biggest offender of the trio – can cause illness for up to 3-weeks after contracting an infection (particularly in a type called “walking pneumonia“). Other types of pneumonia can clear up in a week, but a cough can persist beyond that.

Vaccines Can Help Prevent Two of These

When it comes to prevention, there are 2-illnesses among colds, flu and pneumonia that can be prevented – can you guess which ones? If you said flu and pneumonia, you’re right (although the vaccines reduce risk, not eliminate it).

This is because there are so many viruses that can lead to a cold, explains Business Insider. “Even the most common among those, rhinovirus, has more than a hundred different strains,” it adds. The urgency to come up with an effective cold vaccine is pretty low on the list, as it’s not generally a threat to most people, it adds.

Don’t Give Colds the Cold Shoulder

While colds are the lowest on the list in terms of danger (compared to flu and pneumonia), we’re not saying you should completely ignore colds, as there are many over-the-counter and home remedies you can try. The common cold will generally clear up on its own after 1 or 2-weeks, but it can still lead to some complications, according to EveryDay Health.

The source says if the patient is a child with a fever, then it warrants a visit to a doctor. Meanwhile, the elderly, smokers, or people with other serious health conditions can experience more intense symptoms from a simple cold, it adds.

When to Bring in Medical Help

WebMD says you should call your doctor if your cold or flu symptoms include a persistent fever and/or coughing, painful swallowing, or persistent congestion and headaches. “If you have pain around the eyes and face with thick nasal discharge after a week, you may have a bacterial infection and possibly need an antibiotic,” it adds.

Pneumonia can become severe enough that you have difficulty breathing or pain while breathing. These are serious symptoms that need immediate attention. Pneumonia can often be treated with antibiotics – unless it’s a viral pneumonia, in which case antibiotics won’t help, it notes. “You’ll need to rest, drink a lot of fluids, and take medicines for your fever,” says WebMD.

Jeff Hayward

Jeff Hayward

Jeff has more than 15 years of experience writing professionally about health, travel and the arts among other subjects. He continuously looks to improve his own overall health through exercise, diet and mindfulness. He is also a proud stay-at-home dad that loves taking photographs both professionally and as a hobby.