Common Cold

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Sneezing, scratchy throat, runny nose—everyone knows the first signs of the common cold, probably the most common illness known. The common cold is caused by a wide array of viruses.

Although the common cold is usually mild, with symptoms lasting 1 to 2 weeks, it is a leading cause of doctor visits and missed days from school and work. It is particularly common in children.


Other Names

  • Rhinitis

Signs and Symptoms

Aerosol from a sneeze. Source: NIH.

Symptoms of the common cold may include:

  • Sneezing
  • Runny nose or stuffy nose
  • Nasal secretions may start clear and later become yellow or greenish
  • Mild cough
  • Sinus pressure
  • Feeling generally unwell (malaise)
  • Headache
  • Burning or tingling in the throat

Children may have a fever up to 102 degrees.

The common cold does not usually involve fever, trouble breathing, coughing up dark material or blood, earache, very swollen glands, severe general weakness (prostration), aches all over the body, or bad sore throat that prevents swallowing. These symptoms suggest possible bacterial infection or influenza (flu).

Symptoms usually go away in about a week or less, but may last as long as two weeks.


The common cold is caused by a virus. There are more than 200 different viruses that can give a person a cold. Usually the specific virus a person has is never identified, but two viruses, parainfluenza and respiratory syncytial virus (RSV), may cause more severe disease in young children by descending to the lungs and affecting breathing. These viruses produce mild illnesses in adults.

Rhinoviruses (from the Greek rhin, meaning "nose") cause about one-third of all adult colds, and are most active in early fall, spring, and summer. Scientists have identified at least 110 distinct rhinovirus types. These agents grow best at temperatures of about 91°F, the temperature inside the human nose.

Coronaviruses also cause many adult colds, primarily in the winter and early spring. Of the more than 30 kinds, three or four infect humans.

Approximately 10%–15% of adult colds are caused by viruses also responsible for other, more severe illnesses: adenoviruses, coxsackieviruses, echoviruses, orthomyxoviruses (including influenza A and B viruses, which cause flu), and enteroviruses, as well as parainfluenza and RSV.

The causes of 30%–50% percent of adult colds, presumed to be viral, remain unidentified. The same viruses that produce colds in adults appear to cause colds in children.

Viruses cannot be killed by antibiotics. Antibiotics should not be given to people with simple colds.


Colds are diagnosed by the presence of typical symptoms, along with the lack of more serious symptoms. Many people can diagnose their own colds, but in some cases, consulting a health care provider can help sort out colds from other illnesses.

Testing for individual virus types is not done except in very young children who are suspected of having parainfluenza or RSV. Depending on how sick the child is, these two viruses may require treatment or even hospitalization.


Holistic and alternative treatments

There is no cure for the common cold, but cold symptoms can be relieved by:

  • Resting in bed
  • Drinking fluids
  • Gargling with warm salt water (1/2 teaspoon salt in 1 cup water) or using throat sprays or lozenges for a scratchy or sore throat
  • Using petroleum jelly to soothe a raw nose

In addition,

  • Honey in hot tea or hot water can relieve cough. Honey is not safe for children under 1 year of age.
  • Elevating the head with extra pillows can relieve nighttime cough.
  • Refraining from smoking is especially important when the throat is already irritated by a cold virus.
  • Infants' noses can be moistened with salt-water drops and cleared with a bulb syringe.
  • Keeping the air humid can help loosen secretions and relieve cough.
  • Chicken soup, a very ancient remedy, can also relieve symptoms, studies show.[1]

There are also many medications available to help relieve symptoms. These medications do not cure colds, but they help patients feel better as their bodies fight the virus.


Over-the-counter cold medicines fall into several categories. Some of them combine various medications into one preparation, but it is better to treat the single most bothersome symptom with an individual medicine for that symptom.

Questions have been raised about the safety of over-the-counter cold medicines in children and whether the benefits justify any potential risks from the use of these products in children, especially in those under 2 years of age. [2] In October 2007, a Food and Drug Administration panel recommended that nonprescription cold medicines not be given to children under the age of 6, because cold medicines do not appear to be effective for these children and may not be safe.


Decongestants relieve stuffy noses. Some are sprayed in the nose, while others are taken by mouth.

  • Decongestants that are sprayed in the nose are called topical decongestants. Usually they include either the ingredient phenylephrine (Neo-Synephrine, Dristan) or oxymetazoline (Afrin). These medications can only be safely used for two to three days. If they are used longer than that, rebound congestion develops which is often worse than the original congestion. This problem may require treatment with steroids. It is entirely preventable by using topical decongestants sparingly. A good time to use them is at bedtime to help with sleep.
  • Decongestants that are taken by mouth are called oral decongestants. A typical ingredient in these medications is pseudoephedrine (Sudafed). They take longer to work than topical decongestants, but can be safely used for up to a week or so. Their side effects include dry mouth, trouble sleeping, urinary retention, and elevated blood pressure.

Cough medicines

Cough medicines relieve coughing. If a dry cough is very bad or interferes with sleep, humid air and extra pillows should be tried first. There are several medications for cough:

  • Expectorants are used in productive coughs. They thin out mucus so that it can more easily be coughed out. Common expectorants contain the ingredient guaifenesin, and include Robitussin, Mucinex, and Vicks 44E.
  • Suppressants are intended to reduce the cough reflex. If a cough is producing mucus, these medications should be used cautiously, because the mucus that is causing the cough needs to be coughed out. Common suppressant medications include the ingredient dextromethorphan, such as Robitussin-DM, or codeine, such as Tylenol 3. It is not clear that these medications work very well, and they can cause side effects if used incorrectly. These medications are not recommended for children.
  • Cough drops often include the ingredient menthol, a mild anesthetic. They can soothe irritated throats but don't typically reduce the urge to cough.

Pain relievers

Pain relievers such as aspirin, ibuprofen, or acetaminophen (Tylenol, for example) can help relieve headache, sore throat, or mild fever.

Children should not be given aspirin for cold symptoms, or for any other viral illnesses. Several studies have linked aspirin use to the development of Reye's syndrome in children recovering from flu or chickenpox. Reye's syndrome is a rare but serious illness that usually occurs in children between the ages of three and 12 years. It can affect all organs of the body but most often the brain and liver. While most children who survive an episode of Reye's syndrome do not suffer any lasting consequences, the illness can lead to permanent brain damage or death. The American Academy of Pediatrics recommends children and teenagers not be given aspirin or medicine containing aspirin when they have any viral illness such as the common cold.

Over-the-counter antihistamines

Nonprescription antihistamines may give some relief from symptoms such as runny nose and watery eyes.


Antibiotics do not kill viruses. They do not help people with colds. Using antibiotics when they aren't needed can kill healthy bacteria in the body and can sometimes lead to new health problems.


There are several ways to prevent the spread of cold viruses.

  • Keeping hands away from the eyes and nose, where viruses can easily enter the body
  • Avoiding others who have colds if possible
  • Staying away from others when infected with a cold
  • Covering the nose or mouth and sneezing or coughing into the elbow rather than the hand
  • Washing hands immediately after coughing into them


Handwashing with soap and water is the simplest and one of the most effective ways to keep from getting colds or giving them to others. When water isn't available, the CDC recommends using alcohol-based products, such as Purell, which are made for disinfecting the hands.


Rhinoviruses can live up to 3 hours on the skin. They also can survive up to 3 hours on objects such as telephones and stair railings. Cleaning environmental surfaces with a virus-killing disinfectant might help prevent spread of infection. There is, however, concern that routine disinfecting of household surfaces may promote the development of resistant bacterial organisms.[3]


Because so many different viruses can cause the common cold, the outlook for developing a vaccine that will prevent transmission of all of them is dim. Scientists, however, continue to search for a solution to this problem.

Unproven treatments


Echinacea is a dietary herbal supplement that some people use to treat their colds. Researchers, however, have found that while the herb may help treat colds if taken in the early stages, it will not help prevent them. Studies in the United States and Europe on using echinacea in children have come to different conclusions, so it is still unclear what, if any, effect echinacea has in preventing or treating colds.[4][5]

Vitamin C

Many people are convinced that taking large quantities of vitamin C will prevent colds or relieve symptoms. To test this theory, several large-scale, controlled studies involving children and adults have been conducted. To date, no conclusive data have shown that large doses of vitamin C prevent colds.[6] The vitamin may reduce the severity or duration of symptoms, but there is no clear evidence of this effect.

Taking vitamin C over long periods of time in large amounts may be harmful. Too much vitamin C can cause severe diarrhea, a particular danger for elderly people and small children.


Honey has been considered to be a treatment for coughs and to soothe a sore throat. A recent study conducted at the Penn State College of Medicine compared the effectiveness of a little bit of buckwheat honey before bedtime versus either no treatment or dextromethorphan (DM), the cough suppressant found in many over-the-counter cold medicines.[7] The results of this study suggest that honey may be useful to relieve coughing, but researchers need to do additional studies.

Honey should never be given to children under the age of one because it can lead to infantile botulism, a serious disease.


Zinc lozenges and zinc lollipops are available over the counter as a treatment for the common cold; however, results from studies designed to test the efficacy of zinc are inconclusive. Although several studies have shown zinc to be effective for reducing the symptoms of the common cold, an equal number of studies have shown zinc is not effective. This may be due to flaws in the way these studies were conducted, or the particular form of zinc used in each case. More studies are needed to find out if zinc really helps.

How The Common Cold is Spread

The common cold is very contagious. People can get colds by:

  • Touching their skin or environmental surfaces, such as telephones and stair rails, that have cold germs on them, and then touching their eyes or nose
  • Inhaling drops of mucus full of cold germs from the air

When someone with a cold wipes or blows their nose, the mucus that comes out is packed with viruses. This means that the used tissue is infectious, as is any skin that was touched by the mucus and anything the person touched with dirty hands.

People with colds are most contagious by the second or third day of their illness. By a week or so, even if they are still having symptoms, they are not usually contagious.

Factors that do not cause colds

There is no firm evidence that people can get a cold from exposure to cold weather or from getting chilled or overheated. However, cold weather may make the lining of the nose drier and more vulnerable to a virus, and the most common cold-causing viruses do survive better when humidity is low during the colder months of the year. One group of researchers in Wales has suggested that if the body gets cold, the tiny blood vessels in the nose reflexively clamp down, and that this leads to increased vulnerability to the virus.[8]

There is also no evidence that the chances of getting a cold are related to factors such as exercise, diet, or enlarged tonsils or adenoids. On the other hand, research suggests that psychological stress and allergic diseases affecting the nose or throat may have an effect on the chances of getting infected by cold viruses.[9]

Interestingly, one small study from the same group in Wales did find evidence that having one's feet chilled caused a common cold in a small proportion of its subjects.[10]


Thanks to basic research, scientists know more about the rhinovirus than almost any other virus, and have powerful new tools for developing antiviral drugs. Although the common cold may never be uncommon, further investigations offer the hope of reducing the huge burden of this universal problem.



People in the United States suffer 1 billion colds each year, according to some estimates. According to the Centers for Disease Control and Prevention (CDC), 22 million school days are lost annually in the United States due to the common cold.

Children have about six to 10 colds a year. One important reason why colds are so common in children is because they are often in close contact with each other in daycare centers and schools. In families with children in school, the number of colds per child can be as high as 12 a year. Adults average about two to four colds a year, although the range varies widely. Women, especially those aged 20 to 30 years, have more colds than men, possibly because of their closer contact with children. On average, people older than 60 have fewer than one cold a year.

Cold season

In the United States, most colds occur during the fall and winter. Beginning in late August or early September, the rate of colds increases slowly for a few weeks and remains high until March or April, when it declines. The seasonal variation may relate to the opening of schools and to cold weather, which prompt people to spend more time indoors and increase the chances that viruses will spread to one person to another.

Seasonal changes in relative humidity also may affect the prevalence of colds, because cold weather may make the lining of the nose drier and more vulnerable to a virus, and the most common cold-causing viruses do survive better when humidity is low during the colder months of the year.

Notable Experts

Cardiff University, Common Cold Centre


  1. Rennard BO, Ertl RF, Gossman GL, Robbins RA, Rennard SI. Chicken soup inhibits neutrophil chemotaxis in vitro. Chest. 2000; 118 ( 10): 1150–1155. Abstract | Full Text
  2. Harris G. Parents Warned Cough Medicines Imperil Infants. The New York Times. April 16, 2007.
  3. 2008 Annual Conference on Antimicrobial Resistance: Abstract S5. June 23–25, 2008
  4. Barrett BP, Brown RL, Locken K, Maberry R, Bobula JA, D'Alessio D. Treatment of the common cold with unrefined echinacea. A randomized, double-blind, placebo-controlled trial. Ann Intern Med. 2002 Dec 17;137(12):939-46. Abstract | Full Text
  5. Millea PJ. Echinacea for the common cold. Ann Intern Med. 2003 Oct 7;139(7):601; author reply 601. Abstract | Full Text
  6. Douglas RM, Hemilä H. Vitamin C for preventing and treating the common cold. PLoS Med. 2005 Jun;2(6):e168; quiz e217. Epub 2005 Jun 28. Abstract | Full Text
  7. Paul IM, Beiler J, McMonagle A, Shaffer ML, Duda L, Berlin CM Jr. Effect of honey, dextromethorphan, and no treatment on nocturnal cough and sleep quality for coughing children and their parents. Arch Pediatr Adolesc Med. 2007 Dec;161(12):1140-6. Abstract | Full Text
  8. Eccles R. Acute cooling of the body surface and the common cold. Rhinology. 2002 Sep;40(3):109-14. Abstract
  9. Cohen S, Tyrrell DA, Smith AP. Psychological stress and susceptibility to the common cold. N Engl J Med. 1991 Aug 29;325(9):606-12. Abstract
  10. Johnson C, Eccles R. Acute cooling of the feet and the onset of common cold symptoms. Fam Pract. 2005 Dec;22(6):608-13. Epub 2005 Nov 14. Abstract | Full Text
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