How do I tell if my kid has a cold or the flu?

Rampant misinformation during cold and flu season's got us feeling ugggghhhhh. |  Penywise  for  Morguefile

Rampant misinformation during cold and flu season's got us feeling ugggghhhhh. | Penywise for Morguefile

Any day now, your social media feeds will flip to kids curled up on the couch with their first school-borne illnesses. 

Cold and flu season leads to lots of unnecessarily worried parents, in large part because the language we use to talk about disease is so confusing. Before you have to stock up on the tissues and chicken soup, take some time to sort the actually scary from the mere scary-sounding. 


The common cold's very name lets us know that the it has been long misunderstood. Centuries before the germ theory of disease, people noticed that they were more ill during periods of cold weather, which is why this seasonal illnesses became known as the "cold." Other researchers have hypothesized that colds are seasonal because humans stay indoors--and thus in closer proximity--during colder weather. 

Colds come from over 200 viruses, the most common of which are the rhinoviruses ("nose" viruses). Recently, researchers have discovered that rhinoviruses have a preference for cooler weather, which may partially explain why there are more colds during fall and winter. 

Kids with colds may have runny noses, sore throats, coughs, and overall tiredness. But they don't need cold medications, many of which are not approved for children under age 4.


Like the word "cold," "flu" tells us a lot about its early origins. The word influenza comes from the Italian for "influence." In its earliest usages, influenza meant that a sick person had been influenced by the stars, a common belief about the origin of illness. Later, people began referring to influenza del freddo (influence of the cold). The name change indicated a serious shift in belief system, as illness was thought to be the result of the weather.

Although we now know the flu to be caused by a virus, influenza del freddo wasn't too far off. Like cold viruses, those that cause the flu prefer a cold and dry habitat, which may be why we see them more during winter.

Cold and flu symptoms often overlap. Like the viruses that cause colds, influenza viruses affect the respiratory system. Influenza viruses offer more of a wallop, leading to fevers and muscle aches in addition to the sore throat, runny nose, cough, and other cold symptoms. The onset of the flu tends to be faster than the onset of a cold as well.  

You may note a few "missing" symptoms from the above list. That's because some of the symptoms most associated with the flue are not caused by influenza viruses. "Flu" is a confusing term because we often use it as a polite euphemism for nausea, vomiting and diarrhea. But that kind of "flu" (which is often referred to as the "stomach flu") is not actually the flu at all, but a different illness called gastroenteritis, which is often caused by food-borne noroviruses and rotaviruses.

The problem of "-itis"

"Cold" and "flu" are useful rhetorical terms. If your kid has a cold, you're probably telling him to drink some juice and head to school. If your kid has the flu, you're probably making chicken soup and letting him binge Netflix Kids.

But as medical terms, "cold" and "flu" are incredibly imprecise, both because they cover a range of possible viruses and symptoms associated with different types of infections. The problem of thinking about illness in this way is that, when we group all these different infections together, any illnesses outside of the "cold" and "flu" group sound terrifying. 

Different viruses have a preference for different areas of the body. The rhinoviruses that cause colds, for example, prefer cooler temperatures, and the nose tends to be cooler than average body temperature. The noroviruses and rotaviruses that cause gastroenteritis ("stomach flu") often hitch rides on food and set up camp in the stomach and intestines. Viruses cause inflammation in their preferred locations, which is why kids get a host of scary-sounding illnesses ending in "itis": conjunctivitis, sinusitis, bronchitis, and so on. 

All of these "itis"es just mean inflammation. From head to toe, there are lots of "itis"es. Here are just a few of the ones that frequently happen in kids: 

Conjunctivitis: Inflammation of the eye. 

Otitis media: Inflammation of the middle ear. 

Sinusitis: Inflammation of the sinuses. 

Pharyngitis: Inflammation of the back of the throat.

Bronchitis: Inflammation of the bronchial tubes that carry air to the lungs.

Gastroenteritis:  Infection of the stomach and intestines.

All of these "itis"es can be caused by viruses. Conjunctivitis (pink eye) is often caused by adenoviruses. Bronchitis can be caused by the same viruses that cause colds and flus. The “itis”es can also come from bacterial infection. When pharyngitis is caused by streptococcus, it's called strep throat. When gastroenteritis is caused by E.coli or salmonella, it's called food poisoning. There can be other causes of inflammation as well, such as allergies, fungi, and chemicals. 

Many of the viruses that cause "itis"es can lead to secondary inflammation. For example, the parainfluenza viruses that cause colds can also lead to croup (inflammation of the upper airway) and pneumonia (inflammation of the lungs).

Does your kid need antibiotics? 

When you're faced with a scary-sounding "itis," don't panic. All itises sound scary. But it helps to remember that "itis" just means inflammation. Words like "cold" and "flue" are much less scary sounding, but both of them cause inflammation too. 

Don't push for antibiotics if your doctor didn't prescribe them. Because many illnesses sound so scary, parents want to do something. But if your kid has the cold or flu, you're dealing with a virus. An antibiotic (literally "anti-bacteria") won't help you. Many of the itises can be caused by both viruses and bacteria. In most cases, the difference doesn't really matter to your sick child, because the symptoms will be mostly the same and will resolve without intervention. In some cases it's important for doctors to treat for possibly dangerous bacteria before they even know whether or not it's there. That's why you'll sometimes get antibiotics for your child's ear infection. 

Where are all the antivirals? 

If antibiotics can help cure a child's ear infection or strep throat, why don't we have more antiviral medications to target their illnesses?

You may not hear about "antivirals" as often as antibiotics. That's because they go by another name. Like "cold" and "flu," which are useful rhetorical terms, the first antivirals also had a useful colloquial name: vaccine. (Fun fact: They were called "vaccines" because they were created from cowpox. In Latin, vacca means "cow.")

Vaccines have helped eradicate a number of truly scary itises. For example, kids today don't suffer from as much encephalitis (inflammation of the brain), thanks to the measles vaccine.