Differences between Common Colds and the Flu
Not All Respiratory Infections are Alike: How to Recognize Influenza
Dec 30, 2008
Influenza is often shortened to the "flu", though this term is also confusingly used to refer to acute viral nasopharyngitis or the "common cold". Cold exposure, however, is not behind either disease; they are both caused by viruses.
Causes
Influenza is caused by the influenza virus, which can be divided into influenzavirus A, B and C all of which can be further divided to serotypes. Type A is the most common of these. Avian influenza (bird flu) and swine flu belong to the influenza virus A type.
There are several types of viruses that can be behind the common cold, primarily rhinoviruses, coronaviruses, metapneumoviruses and adenoviruses. Human parainfluenza virus, respiratory syncytial virus (RSV) and some enteroviruses can also cause similar symptoms, but especially the first two often tend to be more severe, even resembling influenza in severity. RSV and parainfluenza can be dangerous to young children.
The common cold can be infective for up to several weeks after symptoms have subsided, which means that avoiding people, especially family members, when they are sick is not a very effective way of cold prevention. Influenza is infective for about ten days, up to two weeks in children.
Symptoms
One thing that usually makes it easy to differentiate between influenza and a common cold is that the onset of the flu tends to be quick and sudden, often starting abruptly with fever and chills, while colds often cause people to feel "they are coming down with something" for several days, before it hits the peak.
The flu is prone to causing fatigue and malaise, which may be severe. Common colds can sometimes cause a fever, but usually only influenza provokes a high temperature. Influenza is more prone to causing "chest cold" and the common cold more likely to lead to a runny and blocked nose.
The flu can sometimes cause vomiting, though usually only in children. It can also cause severe headaches, joint and muscle aches, appetite loss and a painfully sore throat. Nonetheless, throat soreness so severe that eating becomes difficult usually indicates that something else is the problem, such as tonsillitis or mononucleosis (glandular fever or "kissing disease").
Severe dyspnea (breathing difficulties), blue lips and chest pain that gets worse when coughing can be signs of pneumonia and one should see a doctor as soon as possible. Both influenza and colds can predispose one to pneumonia by damaging the lining of the respiratory tract, paving way for bacteria to enter. Influenza in itself can also cause viral pneumonia.
Ear pain can be a sign of an ear infection, but they almost always go away on their own, even without antibiotics. Children are usually given antibiotics anyway, to calm their parents who are anxious about the child crying in pain.
Treatment and Prevention
There is a vaccination and several antiviral drugs for influenza, but they are not effective against the viruses that cause the common cold. There are no current pharmaceutical treatments for the common cold, except for painkillers, antihistamines, decongestants and other symptom-based treatments.
An antiviral drug called pleconaril is effective against several kinds of viruses that can be behind the common cold, but it is still in clinical trials. There are also several RSV drugs and vaccinations in trials, because RSV infections cause thousands of children to be hospitalized every year.
It would certainly be nice if there was a vaccination for the common cold, but considering the wide variety of viruses that can cause this illness, it is unlikely to be achieved. The most effective way to prevent colds is to wash your hands thoroughly with soap. The jury is still out on the effectiveness of remedies like zinc, vitamin C and echinacea.
