Flu Symptoms: How To Tell If You Have The Flu

With news spreading that this year's flu virus may be more severe than in years past, it's understandable to feel some anxiety. In fact, the CDC is reporting that 29 states are experiencing a more widespread and virulent flu than last year's strain, though doctors suggest that the actual strains are not so different from each other.

“Reports of influenza-like-illness (ILI) are nearing what have been peak levels during moderately severe seasons,” Dr. Joe Bresee, Chief of the Epidemiology and Prevention Branch in CDC’s Influenza Division, said in a statement. “While we can’t say for certain how severe this season will be, we can say that a lot of people are getting sick with influenza and we are getting reports of severe illness and hospitalizations."

The measure used by the CDC to determine prevalence of ILI is based on reports from a sample of around 3,000 health care providers of how many patients are visiting them with flu-like symptoms. So far, about 5.6 percent of Americans have come in with some type of flu symptom. As Slate points out, that's fewer than the six percent who appeared in doctors' offices during the 2007/2008 season and definitely fewer than the 7.7 percent of those who appeared at doctor's offices during 2009's H1N1 "swine flu" pandemic.

It's important to look closely at that metric: people with symptoms that could be attributed to flu, who went to the doctor. Higher numbers may indicate a more widespread virus -- or more widespread concern over the virus, leading to more hospital visits. ILI is also not the same as confirmed flu cases -- many of the symptoms that can indicate flu could also be signs of a cold or another type of virus.

"Think of the flu as a respiratory infection that causes systemic effects," explains Dr. Travis Stork, ER physician and co-host of "The Doctors." "In addition to a dry cough you can also have fever, body aches, chills, and a headache. The flu can make you feel miserable 'all over' and in some cases, can lead to serious illness in susceptible individuals. A cold on the other hand is a localized upper respiratory infection primarily with symptoms from the neck up."

With that in mind, what are the symptoms of flu? And when is it time to see the doctor?


Some differences: the flu virus is more likely to cause fever -- and a higher fever, at that. Flu sufferers have more severe symptoms overall and are more likely to face fatigue, body aches and a dry cough. Cold sufferers, by contrast, more commonly have a stuffed or runny nose and respiratory congestion. Some flu sufferers also have intestinal symptoms, such as vomiting or diarrhea.



"Reasons to visit the ER include severe dehydration, lethargy, confusion, or any other truly concerning symptom," Stork says. "What seems like the flu is not always the flu and vice versa and sometimes a visit to the ER is needed to properly diagnose and treat."

Watch The Doctor's discuss the cold vs. the flu in this clip: