Bay Area Medical Information
What's the difference between a cold and the flu?
On this page:
Symptoms of the flu | Is it a cold, the flu, or hayfever? Home Page

Symptoms of the flu -- "It's like being hit by a truck"

The flu puts people in bed Influenza typically comes on suddenly and hits hard. In fact, many people who become sick with the flu say it's like being hit by a truck. The flu virus is generally unforgiving, usually reducing its victims to bedrest for at least a day or so.

The initial distinguishing characteristics of the flu are severe body and joint aches, whereas the simple, common "cold" begins with symptoms limited to the head such as nasal congestion, sore throat, and headache.

Swine flu has the same potential symptoms as seasonal influenza or bird flu — fever, cough, sore throat, body aches, headache, chills and fatigue. There's really no way to know the specific influenza type except by testing. Your doctor can take a sample from your nose or throat with a cotton swab and determine very quickly whether or not your have the flu. To further identify Swine Flu, the swab will need to be sent to the Health Department for further testing.

The flu and the common cold are both respiratory illnesses, but they are caused by different viruses. Cold symptoms are most often much milder than flu symptoms. The virus that causes influenza impacts the entire body with fatigue, fever, muscle and joint aches, and targets the entire repiratory system which starts at the nose, and includes the throat, bronchial tubes, and possibly the lungs. In contrast, the virus that causes the common cold infects only the upper respiratory tract--the nose and throat.

While influenza does have an impact on the total body, it mainly targets the respiratory tract and usually not the gastrointestinal tract (the stomach and intestines). In adults, the flu is generally not associated with nausea, vomiting, or diarrhea. Children, however, may have gastrointestinal symptoms with the flu. What some people call "stomach flu" or "intestinal flu" is really a different type of virus that targets the gastrointestinal tract and causes vomiting and diarrhea. In fact, these symptoms can be caused by many different viruses, bacteria, or even parasites but these problems are rarely the main symptoms of influenza.

Symptoms: Influenza symptoms usually come on suddenly and hit hard

Symptoms of the flu include:

  • fever (usually high)
  • headache
  • muscle/joint aches
  • extreme tiredness
  • dry cough
  • sore throat
  • head congestion with a runny or stuffy nose
  • stomach symptoms, such as nausea, vomiting, and diarrhea, are not typical symptoms of influenza, but can occur. These symptoms are more common in children than adults.

How long do these symptoms last?

After 5 to 7 days, the worst symptoms related to the influenza virus have usually disappeared, but a cough and weakness may persist for two or more weeks. Complications from the flu, however, can worsen or prolong symptoms and require medical attention:

  • Secondary bacterial infections can set in as the flu is resolving. A common sign of this occurring is when someone who has been sick from the flu, starts to feel better, then starts feeling sick again. In this case, a secondary bacterial infection may be setting in causing either sinusitis, ear infections, bronchitis, or pneumonia.
  • Pre-existing chronic medical conditions, such as congestive heart failure, asthma, or diabetes, can worsen as a complication of influenza.
  • Dehydration also can occur as a result of a high fever, excessive sweating and drinking inadequate fluids. (Vomiting or diarrhea, if present, is a common cause from dehydration.) Dehydration can occur in anyone, but it is most serious in babies, small children, and older adults.
  • On rare occasions, influenza virus infection also has been associated with such complications as encephalopathy, transverse myelitis, myositis, myocarditis, pericarditis, and Reye syndrome.

Influenza can lead to life-threatening complications particularly in older people, young children, and people with chronic medical conditions. Every year in the United States more than 200,000 people are hospitalized from flu complications, and about 36,000 people die from the flu.

Is it the flu, a cold, or hay fever?

Hay Fever
Cough Common Common Sometimes
General aches and pains Severe Slight Never
Fatigue, weakness Severe Sometimes Sometimes
Itchy eyes Rare or never Rare or never Common
Sneezing Severe Common Common
Sore throat Common Common Sometimes
Runny nose, stuffy nose Common Common Common
Fever Common Rare Never
Duration 1 to 2 weeks 3 to 14 days Weeks (ex: 6 wks for ragweed or grass pollen seasons) Check the pollen count
Read more:
Written by N Thompson, MSN, ARNP, Last updated April 2009

~Make your home page and gateway to the World Wide Web~
This is an up-to-date educational source for patient education. Health care providers may feel free to print out copies for their patient's use. Please note that content may not be copied for resale or other commercial use such as for web sites. The content on this site is for informational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment.   Never disregard professional medical advice or delay in seeking it because of something you have read on this site. 
Home | About Us | Advertise | Contact Us |Terms of Use | Privacy Policy
©2015 Bay Area Medical Information (™ All Rights Reserved
Google |Yahoo |  MSN |  AOL |  Netscape |  Earthlink |  Dogpile |  All the Web | AltaVista