Updated: Nov 21, 2021
We have all struggled with the symptoms of a cold or flu or an upper respiratory tract infection (URTI). But can you tell the difference between a cold or the flu? Can you distinguish between a bacterial or viral infection? Do you know when should you seek medical help or consider antibiotics?
I have found there are number of misconceptions regarding the dreaded flu and the use of antibiotics, so lets get the facts straight here.
What is the difference between a cold, flu and upper respiratory infection?
An upper respiratory tract infection (URTI) is an infection in any of the components of the upper airway. This includes the sinuses, nasal passages, mouth and back of the throat (pharynx and larynx), and the windpipe (trachea).
The common cold (nasopharyngitis) is inflammation of the nares (nose), pharynx, hypopharynx, uvula, and tonsils and is also considered an URTI.
Any number of different microbes (bacteria, virus, or fungus) can cause a cold or respiratory infection, but most commonly it is viral in origin.
The flu is caused by the influenza virus and can also cause symptoms of an upper respiratory tract infection.
Another common virus with similar symptoms is the is the coxackie virus. It is also one cause of the common cold.
Common symptoms of all include, sneezing, a runny or blocked nose, a scratchy or sore throat, fatigue, and sometimes a cough, fever or diarrhea.
We can even have the same viral or bacterial infection but present with slightly different symptoms.
Is it a cold or the flu?
Since the symptoms are similar, it is very difficult to tell the difference between a cold or the flu. However fever, body aches, a sudden onset & extreme tiredness are rare with a common cold virus but are more common and intense with the influenza (flu) virus.
Is it bacterial or viral?
Despite common belief, yellow or green mucus or snot does NOT mean it is a bacterial infection. In fact it is a sign that your immune system is doing its job. (1)
As white blood cells that help to fight the infection are exhausted and die, they leave a yellow or green tinge to the mucus.
It can be challenging to determine whether an infection is caused by a bacteria, fungus or virus. Many ailments - such as pneumonia, meningitis, diarrhea, ear infections and upper respiratory tract infections - can be caused by either type of microbe.
Blood tests can help, and in some cases a swab can be taken of the infected area and a culture grown to see what microbes are present. This can also help determine if antibiotics are appropriate and if so, what type is best. But remember antibiotics are only beneficial for bacterial infections. Also bacterial infections typically last longer than viral ones.
Anti-biotics or not?
As already mentioned most URTIs are caused by viruses and will resolve without any intervention within 3 to 14 days. Given that viruses do not respond to antibiotics, a wait and see approach may be best before taking a course of antibiotics.
Remember that antibiotics also kill the beneficial bacteria in the gut that are the key to a healthy immune system. So if antibiotics are absolutely necessary, a course of probiotics that help restore the healthy gut flora is important.
A recent review has shown that shorter courses of antibiotic therapy is greatly preferable to longer courses of therapy. The New Antibiotic Mantra should be “Shorter Is Better”. (2)
This approach may reduce the chance of the bacteria mutating and adapting, and prevent the rise of super bugs (bacteria that do not respond to antibiotics). Of course, saving antibiotics for when they are really necessary will also help. Because what happens when antibiotics don't work any more? Check out this great Ted talk on the subject.
When should you visit your GP or seek medical help?
If you answer yes to any of the following questions then you should seek medical help: (3)
Are the symptoms severe and worsening? (In the first few days of the illness this may be OK, as long as none of the other signs below are present).
Is there any difficulty breathing or swallowing? (In babies and young children, are they grunting, or are their nostrils flaring? Are they not feeding, passing urine or do they appear dehydrated?).
Is there any neck stiffness (difficulty or pain when putting their chin to their chest?)
Is their heart beating very fast?
Is there difficulty communicating or responding to social cues?
Are they difficult to rouse from a sleep?
Is there a red/purple pinprick like rash that doesn't disappear when you press on the skin?
Are they hallucinating?
Has there been a fever for longer than 5 days? Or in babies aged 0-3mths is their temperature at or above 38 deg celcius? Or babies aged 3-6 months above 39 degrees celcius? (Please NOTE: A fever is a highly beneficial response to an infection. Most do not go above 40.5 degrees and typically peak in the late afternoon. (3) Taking a medication simply to lower a temperature is not recommended and may prolong the illness. However in very young children, a fever above 38 should always be further investigated).
Why do some get sick and others don't?
Before you blame your work colleague or you grandkids for your illness, consider this...
germs are everywhere! The supermarket trolley, the escalator rail, on the cash you handed over at the coffee shop. In fact the average office desk has 400 times more bacteria than a toilet. Every minute of every day you are exposed to germs.
If a room full of people are exposed to exactly the same germ or bug, do all of them get sick? Not usually, some seem to have a better natural ability to fight off an infection. You see, how well your IMMUNE SYSTEM is functioning is more important than how many bugs you are exposed to.
Want to know how to boost your immune system? Head on over to You are 90% bugs, but are you the right kind? And 6 Simple Steps to Heal You Gut & Boost Your Immune System. Or already sick? Try these top 5 tips to ease symptoms and potentially reduce the duration of the illness.