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Cold vs Flu

Cold versus Flu: How to Recognize and Treat Your Symptoms

By Julia Blank, MD

They're everywhere these days:  the sneezers, the coughers, the folks with runny noses and tissues clutched in hand.  The flu is back.  Or is it the common cold?  How do you tell the difference?  How do you avoid catching it-or if you've got it, how do you treat it and avoid passing it on?

It's often hard to differentiate between the common cold and influenza (or "the flu").  They can both start with a scratchy or sore throat, nasal congestion, runny nose, and cough.  Colds are usually less severe, and last seven to ten days (though they may last longer, especially in children, the elderly, and people with chronic health problems).  The flu is typically more severe, often with a high fever (101-104 F) that can last three to four days, chills, headache, body aches, and fatigue.  Most flu sufferers recover within a week or two, but elderly and debilitated patients may feel weak and tired long after the other symptoms have resolved.

Sometimes, colds and flu can lead to complications, such as secondary infections of the sinuses (sinusitis) or lungs (bronchitis, pneumonia).   They can also result in worsening of underlying medical conditions, such as heart disease, lung disease, or diabetes.  If you have any of these conditions, see "When should you see your doctor," below.

What causes colds and flu?

In a word: viruses. There are over 250 viruses that can cause the common cold, and dozens that can cause the flu.

Most adults experience two to four colds each year, while children have as many as six to eight.  Each year, over 90 million Americans come down with the flu; of these, over 100,000 people end up hospitalized, and between 20,000 and 36,000 people die.  According to the Centers for Disease Control and Prevention (CDC), the 2003-2004 flu season hit hard in October, and is expected to run through March.

Cold and flu viruses are transmitted from person to person via respiratory droplets through sneezing, coughing, and touching contaminated surfaces like telephones and doorknobs.

How can you lower your risk of infection?

Wash your hands!  The CDC recommends routinely scrubbing your hands with soap and warm water for 15 seconds.  Make a habit of this, especially after coming into contact with someone who is ill, or after touching contaminated surfaces-and never touch your eyes, nose, or mouth until you've washed your hands!  Consider using disinfectant sprays or wipes to clean contaminated surfaces; alternatively, you can make your own disinfectant solution by mixing one part bleach to 10 parts water.

If possible, stay away from people who are ill.  Unfortunately, cold and flu symptoms often manifest after a person is already infectious.   People who are at higher risk (infants under 6 months old, elderly, and people with chronic conditions like diabetes, HIV, and cancer) should try to minimize their exposure to crowds.

Get a flu shot! The best time to do this is October - December.  The CDC recommends immunization of anyone six months or older who is at high risk for complications from influenza; this includes people with chronic heart problems, lung problems (such as asthma and emphysema), diabetes, kidney disease, cancer, HIV/AIDS.  Children between 6 and 23 months, adults over age 50, pregnant women in their second or third trimester, and healthcare workers should also get vaccinated.

Side effects from the vaccine include soreness at the injection site, and a day or so of low-grade fever and body aches.  The latter symptoms reflect the "gearing up" of the immune system in response to the vaccine; it takes about 2 to 3 weeks for immunity to fully develop. Each year a new vaccine is manufactured, based on the three most prevalent strains of influenza virus from the previous flu season.  The virus is killed, so you cannot "catch" the flu from the vaccine.  This year's vaccine, unfortunately, did not protect against the Fujian flu, which was the predominant strain reported to the CDC between October and December 2003.  

For those who are shot-leery, the vaccine now also comes in a nasal spray.  The spray is recommended for healthy five- to 49-year-olds who wish to decrease their risks of catching the flu.

Who should not get the flu vaccine?  People who are allergic to eggs or any component of the flu vaccine, and people with a history of Guillain-Barre syndrome.  Also, anyone who has a fever should wait until the fever has resolved.  To date, there is no vaccine against the common cold.

What should you do if you catch a cold or the flu?

"Rest, drink plenty of fluids, and call your doctor in the morning."  While rest and drinking fluids (the non-alcoholic, non-caffeinated kind) are great ideas, most colds do not require a doctor's visit.  The exceptions would be if you have a serious underlying medical condition, such as heart disease, lung disease, or diabetes; if your symptoms last longer than what you might expect from a typical cold; if your symptoms become more severe over time, suggesting a complication such as sinusitis, bronchitis, or pneumonia; or if you are at high risk for complications from the flu (see below).

Over-the-counter medications.  There is a plethora of choices available, so make sure you are using a medication that is appropriate for your symptoms.  For example, if you have nasal congestion, a decongestant might help.  For fever, headache, and minor aches, choose Tylenol or ibuprofen.  Read  the labels carefully, with special attention to the list of active ingredient and dosage instructions; if you're taking more than one medication, do not duplicate or overdose on the ingredients.  Using a multi-symptom combination medication may expose you to medicine-and side effects-that you don't need:  a cough-suppressant ingredient, for example, won't help if you don't have a cough.  Also, be sure to check the package for precautions and medication interactions-or check with your doctor if you are on prescription medications regularly.  People on blood thinners, for example, should not take any medicine containing ibuprofen or other non-steroidal anti-inflammatories (NSAIDs); people with high blood pressure or prostate problems should not take decongestants without checking with their doctor first.  Children and teenagers with viral symptoms should not be given medications containing aspirin because of the associated risk of developing Reye's syndrome.

Over-the-counter supplements.  Vitamin C, Zinc, and Echinacea are sometimes touted for the prevention or treatment of colds and flu.  Unfortunately, there is no conclusive evidence on the benefits or efficacy of these remedies.  Furthermore, since herbs and supplements are not regulated by the FDA, there is no standardization of dosages or quality control of these products-so what the label says may not necessarily correspond to what's in the bottle.  Bottom line:  always let your doctor know about the herbal remedies and vitamin supplements you take, and use these products with extreme caution!

Prescription medications.  If you think you have the flu, or are at high risk from complications of the flu, see your doctor with a day or two of when your symptoms start.  While there are no medications specifically against cold viruses, there are several prescription anti-viral medications for Influenza A and B.  These are most effective when begun within 48 hours of onset of symptoms, and may help to decrease the severity of the symptoms, as well as shorten the duration of the illness by a day or two.  Tamiflu (oseltamivir) is a pill that can be prescribed either for treatment of flu, or for prophylaxis of patients exposed to the flu; it is approved for ages over one year old.  Relenza (zanamivir) is an inhaler for treatment of influenza, approved for patients over seven years old; it can cause bronchospasm and therefore should not be used in patients with asthma or emphysema.  There are also two older antiviral medications, amantadine and rimantadine, which are available for the treatment or prophylaxis of Influenza A only.

A note on antibiotics.  Since both colds and flu are caused by viruses, not bacteria, antibiotics will not help; they may actually be harmful, because they can cause side effects such as diarrhea or yeast infections, without providing any benefit for the illness on hand.  However, if you develop complications from the initial viral infection, such as sinusitis or pneumonia, this secondary illness may be caused by a bacterial infection-and your doctor may prescribe an antibiotic to treat it.

When should you see your doctor?

If you are at high risk for complications from the flu.  This includes:

  • Seniors (65 or older)
  • People with chronic medical conditions such as heart disease, lung disease or asthma, diabetes, cancer, or HIV
  • Pregnant women
  • Children between 6 and 23 months of age

If you have any "red flag" symptoms.  These require urgent medical attention; call your doctor, go to the urgent care center, or head straight for the emergency room if it's after hours.  (See our office locations and urgent care location pages for office hours.)

In children, "red flags" include:

  • Rapid breathing or difficulty breathing
  • High or prolonged fever
  • Inability to hold down fluids or refusal to drink fluids
  • Change of mental status, including irritability that cannot be soothed, inconsolable crying, decreased interaction with the parent or environment, not waking up, convulsions or seizures
  • Worsening of any chronic medical condition

In adults, "red flags" include:

  • Shortness of breath or difficulty breathing
  • High or prolonged fever
  • Chest pain or pressure
  • Confusion
  • Severe or prolonged vomiting
  • Fainting or near-fainting

For more information on colds and flu, see the following related links.