Common cold versus flu: how to tell the difference

how to tell the difference between flu and cold Parents often ask how they can tell if their child has the flu or just a common cold. Here’s how:

Colds, even really yucky ones, start out gradually. Think back to your last cold: first your throat felt scratchy or sore, then the next day your nose got stuffy or then started running profusely, then you developed a cough. Sometimes during a cold you get a fever for a day or two. Sometimes you get hoarse and lose your voice. Kids are the same way. They often feel tired because of interrupted sleep from coughing or nasal congestion.

Usually kids still feel well enough to play and attend school with colds, as long as their temperatures stay below 101°F and they are well hydrated and breathing without any difficulty. The average length of a cold is 7-10 days although sometimes it takes two weeks or more for all coughing and nasal congestion to peter out.

Important news flash: the mucus from a cold can be thick, thin, clear, yellow, green, or white, and can change from one to the other, all in the same cold. The color of mucus does NOT tell you if your child needs an antibiotic and will not help you differentiate between a cold and the flu.

The flu, caused by influenza virus, comes on suddenly and makes you feel as if you’ve been hit by a truck. Flu always causes fever of 101So, if your child has a runny nose and cough, but is drinking well, playing well, sleeping well and does not have a fever and the symptoms have been around for a few days, the illness is unlikely to “turn into the flu.”

Remember: colds = gradual and annoying. Flu = sudden and miserable.

Fortunately, a vaccine against the flu can prevent the misery of the flu. In addition, vaccines against influenza save lives by preventing flu-related complications that can be fatal such as pneumonia, encephalitis (brain infection), and severe dehydration.

Be sure to read our article on ways to prevent colds and flu and our thoughts on over the counter cold medicines. Now excuse us while we go out to buy really yummy smelling hand soap to entice our kids to wash germs off their hands. After that you’ll find us cooking up a pot of good old-fashioned chicken soup, just in case…

Julie Kardos, MD and Naline Lai, MD
revised from a Sept 2009 post