Cold and Flu Differences

I am a physician (an anesthesiologist) and I have continued to try to (silly me) find a really good description of the difference between Flu and Cold. This has really been nagging me, not only for my kids, but for me as well.
I did see the excellent article that you have on the site regarding not using antibiotics for colds. I couldn’t agree more! Do you feel antibiotics are overused for ear infections too, which after all may frequently be caused by colds?
Thank you.

Allan Zacher, MD

Cold and Flu Differences

Dr. Greene`s Answer:

I am so glad you asked this question. Cold and flu have become an inseparable pair, like salt and pepper or New Year’s and weight loss. Walking down the “cold and flu” aisle of any drugstore, you will find stacks of bright boxes with bold claims of help for those suffering from a cold or the flu. Since the two illnesses share some similar symptoms, and both come during “cold and flu season,” the two often run together in people’s minds. We have a vague idea that they are different, but if pressed, have a hard time saying exactly how. The significant distinctions between these two common conditions elude most of us, but the question is rarely raised.

The symptoms we get during a viral illness are often the body’s attempt to get rid of the virus and to minimize damage. Sneezing ejects the virus from the nose, cough from the lungs and throat, vomiting from the stomach, and diarrhea from the intestines. Fever makes it difficult for the virus to reproduce. The topic of viral illnesses will always remain somewhat confusing, since the body has a relatively small number of symptoms with which to respond to an ever-changing, wide variety of viruses. While colds and flus may overlap, the differences between them are important.

The common cold is centered in the nose.

Over 200 different types of viruses can cause a cold. Rhinoviruses, which means “nose viruses”, are the most common cause. Respiratory syncitial viruses (RSV) and a host of others can produce colds. Of note, influenza viruses occasionally cause illnesses with symptoms of the common cold.

The three most frequent symptoms of a cold are nasal stuffiness, sneezing, and runny nose. Throat irritation is often involved (but not with a red throat). Adults and older children with colds generally have minimal or no fever. Infants and toddlers often run a fever in the 100 to 102 degree range.

Depending on which virus is the culprit, the virus might also produce a headache, cough, postnasal drip, burning eyes, muscle aches, or a decreased appetite, but in a cold, the most prominent symptoms are in the nose. (By the way, forcing a child to eat with a decreased appetite due to a cold is both unnecessary and unhelpful, but do encourage drinking plenty).

If anything, using the term “common” with cold is an understatement. Colds are the most prevalent infectious disease. Children average 3 to 8 colds per year (younger children and boys are on the higher end of the range). Colds occur mostly in the winter (even in areas with mild winters). In areas where there is no winter, colds are most common in the rainy season. Parents get about half as many colds as their children do. Moms tend to get at least one more cold per year than dads.

When someone has a cold, the nasal secretions are teeming with cold viruses. Coughing, drooling, and talking are all unlikely ways to pass a cold. But sneezing, nose-blowing, and nose-wiping are the means by which the virus spreads. You can catch a cold by inhaling the virus if you are sitting close to a sneeze, or by touching your nose, eyes, or mouth after you have touched something contaminated by infected nasal secretions.

Once you have “caught” a cold, the symptoms begin in 1 to 5 days. Usually irritation in the nose or a scratchy feeling in the throat is the first sign, followed within hours by sneezing and a watery nasal discharge.

Within one to three days, the nasal secretions usually become thicker and perhaps yellow or green — this is a normal part of the common cold and not a reason for antibiotics. During this period, children’s eardrums are usually congested, and there may well be fluid behind the ears — whether or not the child will end up with a true bacterial infection. Yes, Dr. Zacher, antibiotics are too frequently prescribed for this as well.

The entire cold is usually over all by itself in about 7 days, with perhaps a few lingering symptoms (cough) for another week. If it lasts longer, consider another problem, such as a sinus infection or allergies.

While it lasts, the common cold is primarily a head cold. While you may feel tired or have aches, the illness is centered in the nose, and most of the symptoms are above the neck.

With the flu, you are sick all over.

The flu can be a much more serious illness. The most deadly recent worldwide outbreak was the flu epidemic at the beginning of this century and killed more than 20 million people. Even today, more than 36,000 people in the United States die from the flu each year — primarily those who are weak from advanced age or a major illness.

A single family of viruses — the influenza viruses — causes the flu. Most people get the flu once every year or two or three, and the illness is unpleasant but not usually dangerous. Unlike the common cold, both adults and children with the flu generally have a fever.

The flu can take many forms, but I will describe for you the most typical:

Classically, the flu begins abruptly, with a fever in the 102 to 106 degree range (with adults on the lower end of the spectrum), a flushed face, body aches, and marked lack of energy. Some people have other systemic symptoms such as dizziness or vomiting. The fever usually lasts for a day or two, but can last five days.

Somewhere between day 2 and day 4 of the illness, the “whole body” symptoms begin to subside, and respiratory symptoms begin to increase. The virus can settle anywhere in the respiratory tract, producing symptoms of a cold, croup, sore throat, bronchiolitis, ear infection, and/or pneumonia.

The most prominent of the respiratory symptoms is usually a dry, hacking cough. Most people also develop a sore (red) throat and a headache. Nasal discharge and sneezing are not uncommon. These symptoms (except the cough) usually disappear within 4 to 7 days. Sometimes there is a second wave of fever at this time. The cough and tiredness usually lasts for weeks after the rest of the illness is over.

Inhaling droplets from coughs or sneezes is the most common way to catch the flu. Symptoms appear 1 to 7 days later (usually 2-3 days). The flu is airborne and quite contagious, and with its short incubation period it often slams into a community all at once, creating a noticeable cluster of school and work absences. The flu usually arrives in the winter months. Within 2 or 3 weeks of its arrival, most of the classroom has had it.

The other major difference between the common cold and the flu is that the flu is preventable. In any given year, two or three different strains of influenza virus cause most of the flu around the world. Each year, scientists gather extensive global data and formulate a vaccine for the strains anticipated to be the major problems in the coming winter. While the prediction is usually accurate, sometimes new, unanticipated strains arise. In other words, in some years the vaccine works better than in others.

The CDC (Centers for Disease Control) currently highly recommends the flu vaccine for all children aged 6 months to 18 years, adults aged 50 years or older; persons aged 5–50 years with underlying chronic medical conditions; all women who will be pregnant during the influenza season; residents of nursing homes and long-term care facilities; children on chronic aspirin therapy; household contacts to any of the above groups; health-care workers involved in direct patient care; and out-of-home caregivers and household contacts of children aged <6 months. When supplies are sufficient, the CDC recommends vaccination of all persons who want to be vaccinated regardless of risk.

I prefer using versions of the flu vaccine without added thimerosal (a form of mercury) as a preservative. Most kids still get the flu vaccines with extra mercury. You might have to request ‘no added mercury’ to get the vaccine you want.

A nasal spray flu vaccine is now commercially available for nonpregnant, healthy people who are aged 5-49 years old. Over the next years it may become the more popular mode of flu vaccination due to its painless administration.

Of note, a new vaccine for pandemic H1N1 (initially referred to as the “swine flu” in the media) will be available in mid-late October 2009. This vaccine will be targeted towards the following high risk groups: pregnant women, household contacts or caregivers for infants less than 6 months, healthcare workers and emergency personnel, children and young adults 6 months – 24 years, and persons 25 years – 64 years with underlying medical problems. The number of doses recommended is similar to the seasonal influenza vaccine: a single dose for older children and adults, and two doses for children younger than 8-9 years of age (the exact age depends on the vaccine manufacturer). The pandemic H1N1 vaccine is expected to have a similar safety profile to the seasonal influenza vaccine.

For both seasonal influenza and pandemic H1N1, there is antiviral therapy available, such as Tamiflu or Relenza. However, antiviral agents – as well as hospitalization – are generally reserved for the very youngest, sickest, and highest risk patients.

Dr. Alan Greene

Dr. Greene is the founder of DrGreene.com (cited by the AMA as “the pioneer physician Web site”), a practicing pediatrician, father of four, & author of Raising Baby Green & Feeding Baby Green. He appears frequently in the media including such venues as the The New York Times, the TODAY Show, Good Morning America, & the Dr. Oz Show.

  1. Bob Down

    Best description I’ve ever read!

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  2. Sunny

    I have had a bad reaction to MCS gotten from T-Shirt out-gassing……it seem to manifest itself with flu or virus symptoms…….my dr said there have been no Flu or viruses reported…….sick for a month…….all the MCS ..symptoms…..in afternoon get flushed and very warm in face…..my dr gave me steroids and then OTC still not feeling better…….primary dr’s are not knowledgable of MCS
    Allergist don’t want to take you …..and only the holistic who don’t take insurance and to do a profile $600.00 to walk in door and then they want to do colonic detoxing and all the other stuff which also runs into lotsa of moola! Any one have any experience with this and maybe shed some light on it! I would like to find a support group as this problem runs rampart among humans……..I don’t know how you change things with naturopaths, etc. to accept ins.

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  3. Jenny-G

    Hello Doc –

    I’m a 33 year old female, usually healthy, but recently I think I contracted either a weird cold or a mild flu. My 22 month old son got the sniffles and a 101.4 fever on Thursday and has been coughing. After a day his fever subsided and was just sniffles and coughing. Then Saturday I caught it so suddenly! One minute I was fine and the next I felt sneezing and very tired with the sniffles. I felt warm, but not sure if it was a fever. I thought I had the cold and was fine when I went to work yesterday (Tuesday), but then I felt feverish and aches all over my body. I feel like I have the start of a flu possibly. Today feeling aches again, less severe compared to yesterday and only slightly nauseated this morning with a slight dry throat. Is this a flu?

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  4. Sam Cota

    Ok so honestly I’m an occasional smoker. Today I woke up with a low fever of around 99.4 and my face is broiling hot but my body is slightly cold. I think it’s the flu but is their any sicknesses with these symtoms caused by smoking when I barely smoke at all?

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  5. helen woods

    .org didn’t answer my question why does my eyerun

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    • C-Fiffle

      Because it’s training for a marathon

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    • J. Shmoody

      Do you clean them at all? Just do the opposite for a while

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  6. Ashok

    Very helpful article ! It helped me to understand that I have a cold and should take only cold medication and not flu medication. I got it yesterday from a co-worker who was sneezing. I am currently taking Echinacea (a herbal tonic which boosts up the immune system) and will see if it helps otherwise will take some cold medications.

    Thanks !
    Ashok

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  7. John Mills

    Can you just get the muscle aches from either ,or as a layered affect of both flu and cold? I’m 61 run 1-3 hrs (twice a week) thought it was delayed onset muscle soreness.
    I’very heard that it can settle in
    the muscle tissue,but it may be
    misinformation.
    Great Article & Thank You for sharing this important information.
    John

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  8. Robert

    You can’t readily diagnose people online. You guys need to stop asking as this sort of stuff is best left to your primary care provider.

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  9. Katie

    I’ve had a head cold for 6 days now. It hit me like a semi and I could not hardly think my head hurt so much. I had the runny and stopped up nose, red throat, and it still lingering, I still am not sure if it was a strong cold or the flu that got me.

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  10. beth

    Can a virus start out as the flu and end as a cold? I’ve been told there’s a flu-cold virus going around. Sounds odd to me.

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    • Katie

      My mom would have said that makes sense. Because if the virus is similar, you’d have cold symptoms that were just a lingering effect of the flu. But it is possible you contrActed somethings else too.

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      • J. Shmoody

        I have gotten both a cold and a flu before. At the same time it is possible. But not often.

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  11. Theresa

    T
    Sunday’s started feeling like I had a cold. Monday I am coughing realy bad I am tired and achy fever of 100.9 is it the cold or flu. Came from Sc to Boston five days ago

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  12. brad lytle

    I contracted flu like symptoms three weeks ago, with the usual, aches, fever, sinus infection and diahrrea. Which then turned to runny nose and chest congestion. I’m on week four and I am still inflicted with a runny nose, persistent couch from chest congestion and once again diahrrea. Should I be concerned and what if any further care can I do to overcome this illness?

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    • Theresa

      Since it has been going on for four weeks. Time to see a doctor!!!
      Good lyck

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  13. Bernice

    Dear DrGreene,

    Hi. I’m currently a med student who just entered clinical years, and I’m trying to figure out what has happened on my friend. I got puzzled making a diagnosis and I hope you may help me with it. Thankyou!
    She presented with two days of mild watery diarrhea, followed by cough and sneeze. She’s afebrile (or in any case, it’s so mild that she didn’t notice it ). And later together with the respiratory tract symptoms, she also found little erythematous papules over her upper lips.

    My question is :
    Can I still say it is flu since she presented with diarrhea as the first symptoms, or it is in fact gastroenteritis? How can I differentiate between two?
    And do you think it is bacterial or viral infection?

    Look forwards to hearing from you.

    Kind regards,
    Bernice

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  14. mukhtar

    Dr,

    I am suffering from runny nose and sneezing since last 10 day, and there is no cough no fever.

    What should I do? I am 23.

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  15. Jacquelin gaurd

    Hi doctor,

    On Wed I felt real tired so I had a nap. When I woke my throat was really sore, I was freezing cold and shivering. The next day my nose was blocked, headache sore throat and body aches. Day 3 my eyes really hurt when I look around. I’m coughing up green stuff and my chest burns when I cough. I’ve got no energy and can hardly breath. Is this a virus or flu???? Thank you.

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    • Dakota Roy MD

      From the symptoms you are experiencing I would reccomend going to your nearest health clinic as soon as possible.
      What you described are very early symptoms of the AIDS HIV virus.
      Be especially worried if all symptoms suddenly stop rather than gradually fade.

      Dakota Roy MD

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  16. Alyssa

    I came down with what feels like the flu about 4 days ago. Started out with a light runny nose and the feeling of something dripping down my throat. Usually with a cold I start with a sore throat and earache…..this was different. Then suddenly, within a few hours I was dealing with aches and pains, cold sweats (feeling sweaty and hot under a blanket, then freezing once the blanket was off). Having a cup of hot tea would make me feel sweaty. I felt like my eyelids were hot, so I took my temperature with a forehead scanning thermometer and it read at 101.3. I had no energy, I came home early from work and slept from noon to 3pm and it took 45 minutes just to get the energy to get out of bed. I had a blazing headache and a horrible sore throat and dry cough. Most of those symptoms are now gone but I’m now on day three and I have no energy. It’s 2pm and I’m still laid out on the couch. I just want to feel normal again.

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  17. tara

    My daughter has been sick with very little breaks in between since at least Feb. When she had cold like symptoms with urinary tract infection, then ear infection. As soon as that was gone, a stomach bug, then back to runny nose and horrible cough, which then ended up with double ear infection and bronchitis. She has been treated with antibiotics, and about 2 days after finishing, here comes a runny nose with congestion. She has a fever, and diarrhea all day yesterday, and threw up last night. We’ve been to the doctors office several times, and ER. We’ve been told it’s a virus. A chest x-ray was taken to make sure she didn’the have pneumonia. Any advice? I can’t stand seeing my baby sick like this, and for so long now.

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  18. mcdonald

    Hey, my life is in a roller coaster right now!!! I’m a 25 year old male and I’ve got the flu. It started with a little sore throat and it disappeared, then diarrhea came with fever. I got meds and now the diarrhea’s gone, but the fever’s still there. This all started on Saturday!!! And I’m so scared of doing a test because I feel it’ll be a HIV symptoms…….Please help me.

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    • li

      Hey McDonald,
      It sounds like it is just the flu. Don’t be scared but it is always good to get an HIV test now and again if you feel you are at risk. Sounds like you have the flu though so try to relax and focus on getting better

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  19. Gayle Allsopp

    I have caught something from my son but I seem to be worse. He had a bad runny nose, cough, aches, headache, loss of appetite and felt really tired. He took cold and flu tablets and they helped him a lot. I have all of the above symptoms with also sweats and shivers and diarrhoea. Is this more likely to be flu than a cold? How long will it last as I’ve had it for 5 days?

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  20. anonymous

    I medicine for a yeast infection. The second dose my throat started to hurt and breathing got a little difficult. I stopped the medicine but I now have a runny nose, congestion, and a very sore throat that feels almost swollen. How long would an allergic reaction last? Could I have gotten sick at the same time as I took medicine? Could this be a cold, flu, or allergic reaction?

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  21. Priya

    I am suffering cough and sort of. Breathing my nighttime is very hard.

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  22. Emily2321

    I have a red nose for the past 2 days. How can I make it go away. It’s not that red and I’m a kid, too — aged 11-12.

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  23. riyaz

    I have a normal cold cough/alergy cough and fever 102 ‘bodyacah is there difference between in cold cough and H1n1 cough plz advised

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  24. Sarah

    I have to say after my son and I had our flu shots in November, we still came down with the classic flu like symptoms in January despite the shot. We are on our 2nd week and the symptoms just seem to be evolving from one thing to the next.

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  25. Jami

    After reading all this, I STILL don’t understand the difference even though this makes the most sense of everything I’ve read about the cold and flu.

    I recently had a very bad cold or flu. I feel like maybe it was a cold, because at first it was very centered around my nose – for about 4 or 5 days. But then it moved to my throat after about day 3 and lasted (very bad) for another 3 or 4 days. On top of that, a sinus infection must have ensued and my nose was very sore for another 4-5 days. And 3 weeks later I STILL have a sore throat, get really thirsty even though I am drinking plenty of fluids and am sleeping more than usual and I don’t understand why.

    I never had a fever because as soon as I started feeling achy and tired, I started taking Advil, which I pretty much kept taking every time I got a muscle ache. So maybe it was the flu?

    On day two, I couldn’t really do much — I laid in bed all day and had to postpone plans. On day three I felt slightly better, but by day 4 I was back in bed again. Dizzy and with the nose dripping and sneezing again.

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    • Perhaps it was / is neither. With the soar throat and sinus infection, perhaps it was Strep or F-throat. If you’re still feeling miserable, you may want to see a doctor and get tested for a bacterial infection. Bacterial infections can be treated with antibiotics (though not always the best plan if your body can fight it off on its own). Viral infections can not be treated with antibiotics.

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  26. Jennifer

    Hi there doctor. First, I am a 29 year old female and I have a couple questions, I have a few autoimmune disorders, such as psoriasis, crohns. I also take immune suppressors, such as humira and I just got off prednisone a month ago. I do take a multivitamins with immune support. This is really concerning me but I have had a cold/flu for 5 days now I have had a fever between 99-100.6, body aches, extreme fatigue, no appetite, nausea, vomiting and a cough. My boyfriend whom I live with got it first and still has a lingering cough. But what do you think this might be, cold or flu? And considering my illnesses, should I seek medical attention? I have had pneumonia before and my right lung is scarred. I’m just not quite sure on what I should do. Any advice I could get I would really appreciate it. Thank you.

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  27. millie

    I got a cold and have been feeling tired all week and can’t stay awake in the day time. What should I do?

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    • s oconnor

      Sleep gives your body the rest it needs, so don’t fight it. When you wonder why you are so tired..it’s because your body is fighting hard to make you well. There’s a war going on inside. All of your energy is thrust into the fight. So sleep. The cat naps will get shorter as your body wins the war..

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  28. Anu

    Hi Doctor,
    My 22 months old daughter has cold( running nose) since from past 15 days. We gave cold syrup for first 5 days and stopped. Still continuing with nasal drops.

    I am bit worried. Do I need to consult doctor or it goes on its own. She die’t have cough or fever. So aim bit relaxed.

    Could you please suggest me on this.

    Kind regards,
    Anu

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  29. Payze Dues

    The CDC? The Center for Disease Creation? Vaccines? “Usually ACCURATE”? Tamiflu? Isnt that Donald Rumsfeld’s brand?Are you a joker? Discussion of vaccine production will turn most people’s stomach.Stop shilling for the establishment.

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    • JD

      I think your tin foil hat might be on a little tight there, Payez. Get a grip, then join the rest of us out here in reality.

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      • T

        I think you need to educate yourself JD, before you spew bullshit from your mouth.

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        • Ura

          Yeah, we see all sorts of anti-vaccers…here in the ICU…:-(

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