Common cold

Definition

The common cold is a viral infection of the upper respiratory system, which includes the nose, throat, sinuses, eustachian tubes, trachea, larynx, and bronchial tubes. Although more than 200 different viruses can cause a cold, 30–50% are caused by a group known as rhinoviruses. Almost all colds clear up in less than two weeks without complications.

Description

Colds, sometimes called rhinovirus or coronavirus infections , are the most common illness to strike any part of the body. It is estimated that the average person has more than 50 colds during a lifetime. Anyone can get a cold, although preschool and grade school children catch them more frequently than adolescents and adults. Repeated exposure to viruses causing colds creates partial immunity.

Although most colds resolve on their own without complications, they are a leading cause of visits to the doctor and of time lost from work and school. Treating symptoms of the common cold has given rise to a multimillion dollar industry in over-the-counter medications, yet none of these medications are actually anti-viral to the rhinovirus.

Cold season in the United States begins in early autumn and extends through early spring. Although it is not true that getting wet or being in a draft causes a cold (a person has to come in contact with the virus to catch a cold), certain conditions may lead to increased susceptibility. These include:

• fatigue and overwork
• emotional stress
• poor nutrition
• smoking
• inadequate rest or sleep
• living or working in crowded conditions

Colds make the upper respiratory system less resistant to secondary bacterial infection. Secondary bacterial infection may lead to a number of other complications, including middle ear infection, bronchitis, pneumonia, sinus infection , or strep throat . People with chronic lung disease, asthma , diabetes, or a weakened immune system are more likely to develop these complications.

Causes & symptoms

Colds are caused by more than 200 different viruses. The most common groups include rhinoviruses and coronaviruses. Different groups of viruses are more infectious at different seasons of the year, but knowing the exact virus causing the cold is not important in treatment.

People with colds are contagious during the first two to four days of the onset of symptoms. Colds pass from person to person in several ways. When an infected person coughs, sneezes, or speaks, tiny fluid droplets containing the virus are expelled. If these are breathed in by other people, the virus may establish itself in their noses and airways.

Colds may also be passed through direct contact. For example, if a person with a cold touches his runny nose or watery eyes, then shakes hands with another person, some of the virus is transferred to the uninfected person. If that person then touches his mouth, nose, or eyes, the virus is transferred to an environment where it can reproduce and cause a cold.

Finally, cold viruses can be spread through inanimate objects (door knobs, telephones, toys) that become contaminated with the virus. This is a common method of transmission in child care centers. Another vector of transmission is air travel, due to closed air circulation in buildings.

Once acquired, the cold virus attaches itself to the lining of the nasal passages and sinuses. This causes the infected cells to release a chemical called histamine. Histamine increases the blood flow to the infected cells, causing swelling, congestion, and increased mucus production. Within one to three days, the infected person begins to show cold symptoms.

The first cold symptoms are usually a tickle in the throat, runny nose, and sneezing . The initial discharge from the nose is clear and thin. Later, it may change to a thick yellow or greenish discharge. Most adults do not develop a fever when they catch a cold. Young children may develop a low fever of up to 102°F (38.9°C).

Other symptoms of a cold include coughing, sneezing, nasal congestion, headache , muscle ache, chills, sore throat , hoarseness, watery eyes, fatigue, dull hearing and blocked eustachian tube (a danger when flying), and lack of appetite. The cough that accompanies a cold is usually intermittent and dry.

Most people begin to feel better four to five days after their cold symptoms become noticeable. All symptoms are generally gone within 10 days, except for a dry cough that may linger for up to three weeks.

Colds make people more susceptible to secondary bacterial infections such as strep throat, middle ear infections, and sinus infections. A person should seek a doctor's consultation if the cold does not begin to improve within a week. If an individual experiences chest pain , fever for more than a few days, difficulty breathing, bluish lips or fingernails, a cough that brings up greenish-yellow or grayish sputum, skin rash, swollen glands, or whitish spots on the tonsils or throat, then that person should also consult a doctor to see if they have acquired a secondary bacterial infection that needs to be treated with an antibiotic.

People who have emphysema , chronic lung disease, diabetes, or a weakened immune system—either from diseases such as AIDS or leukemia , or as the result of medications, (corticosteroids, chemotherapy drugs)—should consult their doctor if they get a cold. People with these health problems are more likely to get a secondary infection.

Diagnosis

Colds are diagnosed by observing a person's symptoms and symptom history. There are no laboratory tests readily available to detect the cold virus. However, a doctor may do a throat or nasal culture, or blood test to rule out a secondary infection.

Influenza is sometimes confused with a cold, but the flu causes much more severe symptoms, and is generally accompanied by a fever. Allergies to molds or pollens also can cause a runny nose and eyes. Allergies are usually more persistent than the common cold. An allergist

or a physician can do tests to determine if the cold-like symptoms are being caused by an allergic reaction. Also, some people get a runny nose when they go out-side in winter and breathe cold air. This type of runny nose, however, is not a symptom of a cold.

Treatment

The patient should drink plenty of fluids and eat nutritious foods. In fact, the old adage, "Feed a cold, starve a fever" was scientifically proven true in 2002. Dutch scientists found that cold-fighting immune responses rose after consuming a full meal while fasting increased those that combat most fevers. Chicken soup with ginger , scallions, and rice noodles is nutritious and has properties that help the patient to recover. Rest, to allow the body to fight infection, is very important. Gargling with saltwater (half teaspoon salt in one cup of water) helps to soothe a sore throat. A vaporizer also will make the patient feel more comfortable. Rubbing petroleum jelly or some other lubricant under the nose will prevent irritation from frequent nose blowing. For babies, nasal mucus should be suctioned gently with an infant nasal aspirator. It may be necessary to soften the mucus first with a few drops of salt water.

Herbals

Herbals can be taken to stimulate the immune system, for antiviral activity, and to relieve symptoms. The following herbs are used to treat colds:

• Ginger (Zingiber officinale ) reduces fever and pain, has a sedative effect, settles the stomach, and suppresses cough.
• Forsythia (Forsythia suspensa ) fruit can be taken as a tea for its anti-inflammatory, fever reducing, and antimicrobial properties.
• Honeysuckle (Lonicera japonica ) flower can be taken as a tea for its anti-inflammatory, fever reducing, and antimicrobial properties.
• Aniseed (Pimpinella anisum ) can be added to tea to expel phlegm, induce sweating, ease nausea , and ease stomach gas.
• Slippery elm powdered bark (Ulmus fulva ) can be taken as a tea or slurry or capsules to soothe sore throat, to ease cough, and to thin mucous.
• Echinacea (Echinacea purpurea or augustifolia ) relieved cold symptoms in clinical studies. The usual dosage is 500 mg of crude powdered root or plant thrice on the first day, then 250 mg four times daily thereafter. This may also be taken as a tincture.
• Goldenseal (Hydrastis canadensis ) has fever reducing, antibacterial, anti-inflammatory, and antitussive properties. The usual dose is 125 mg three to four times daily. Goldenseal should not be taken for more than one week. Goldenseal may also be prepared as a tincture.
• Astragalus (Astragalus membranaceus ) boosts the immune system and improves the body's response to stress. The common dose is 250 mg of extract four times daily.
• Cordyceps (Cordyceps sinensis ) modulates and boosts the immune system and improves respiration. The usual dose is 500 mg two to three times daily.
• Elder (Sambucus ) has antiviral activity, increases sweating, decreases inflammation, and decreases nasal discharge. The usual dose is 500 mg of extract thrice daily.
• Stinging nettle (Urtica dioica ) has antihistamine and anti-inflammatory properties. The common dose is 300 mg four times daily.
• Schisandra (Schisandra chinensis ) helps the body fight disease and increases endurance.
• Grape (Vitis vinifera ) seed extract has antihistamine and anti-inflammatory properties. The usual dose is 50 mg three times daily.
• Eucalyptus (Eucalyptus globulus ) or peppermint (Mentha piperita ) essential oils added to a steam vaporizer may help clear chest and nasal congestion and disinfect room air.
• Boneset infusion (Eupatroium perfoliatum ) relieves aches and fever.
• Yarrow (Achillea millefolium ) is a diaphoretic.
• Supplemental larch from the inner bark of the western larch tree has been shown in some clinical trials to fight persistent colds and ear aches.

Chinese medicines

Chinese herbal treatments are based on the specific symptoms of colds and include a variety of Radix, Rhizoma, Semen, and Herba species. Chinese patent medicines for cold include:

• Wu Shi Cha (Noon tea): once or twice daily.
• Yin Qiao Jie Du Pian (Honeysuckle and Forsythia Tablet to Overcome Toxins): four to six, twice daily.
• Sang Ju Gan Mao (Mulberry Leaf and Chrysanthemum to Treat Common Cold): one packet of infusion or four to eight tablets, twice or thrice daily.
• Ling Yang Gan Mao Pian (Atelopis Tablet for Common Cold): four to six, twice daily.
• Ban Lan Gen Chong Ji (Isatidis Infusion): one packet twice or thrice daily.
• Huo Xiang Zheng Qi (Agastache to Rectify Qi): 6 g or four to six tablets.

Other remedies

The effectiveness of zinc lozenges for preventing or treating the common cold is controversial. Numerous studies have generated contradicting results. It has been suggested that the citric acid, sorbitol, or mannitol in some lozenges may bind zinc and reduce effectiveness, hence the varying results of these studies. The recommended dosage is to suck on one lozenge every two hours while awake beginning at the first cold symptoms. Side effects are bad taste, nausea, and vomiting .

Ayurvedic medicine practitioners recommend gargling with a mixture of water, salt, and turmeric powder or astringents such as alum, sumac, sage , and bayberry to ease a sore throat.

Homeopaths recommend microdoses of Viscue album, Natrum muriaticum, Allium cepa, or Nux vomica.

Allopathic treatment

There are no known medicines proven to shorten or cure the common cold. Antibiotics are useless against a cold, and can enhance bacterial resistance, if used carelessly. Nonprescription products to relieve cold symptoms usually contain antihistamines, decongestants, and/or pain relievers. Over-the-counter cold remedies should not be given to infants without consulting a doctor first. Care should be taken not to exceed the recommended dosages, especially when combination medications or nasal sprays are taken. Aspirin should not be given to children with a cold because of its association with a risk of Reye's syndrome, a serious disease.

Antihistamines are taken to relieve the symptoms of sneezing, runny nose, itchy eyes, and congestion. Side effects are dry mouth and drowsiness, especially with the first few doses. Some people have allergic reactions to antihistamines. Common over-the-counter antihistamines include Chlor-Trimeton, Dimetapp, Tavist, and Actifed. The generic name for two common antihistamines are chlorpheniramine and diphenhydramine.

Decongestants reduce congestion and open inflamed nasal passages, making breathing easier. Decongestants can make people feel jittery or keep them from sleeping. They should not be used by people with heart disease , high blood pressure, or glaucoma . Some common decongestants are Neo-Synepherine, Novafed, and Sudafed. The generic names of common decongestants include phenylephrine, phenylpropanolamine, pseudoephedrine, and in nasal sprays naphazoline, oxymetazoline, and xylometazoline. Nasal sprays and nose drop decongestants can act more quickly and strongly than ones found in pills or liquids because they are applied directly in the nose. Congestion returns after a few hours. Persons can become dependent on nasal sprays and nose drops, so they should not be used for more than a few days.

Many over-the-counter medications are combinations of both antihistamines and decongestants; an ache and pain reliever, such as acetaminophen (Datril, Tylenol, Panadol) or ibuprofen (Advil, Nuprin, Motrin, Medipren); and a cough suppressant (dextromethorphan). Common combination medications include Tylenol Cold and Flu, Triaminic, Sudafed Plus, and Tavist D.

Expected results

Given time, the body will make antibodies to cure itself of a cold. Most colds last seven to 10 days. Most people start feeling better within four or five days. Occasionally, a cold will lead to a secondary bacterial infection that causes strep throat, bronchitis, pneumonia, sinus infection, or a middle ear infection.

Prevention

Prevention focuses on strengthening the immune system by eating a healthy diet low in sugars and high in fresh fruits and vegetables, practicing meditation to reduce stress, getting adequate sleep, and getting regular moderate exercise . Some steps persons can take to prevent catching a cold and to reduce their spread include:

• washing hands well and frequently
• covering the mouth and nose when sneezing
• avoiding close contact with someone who has a cold during the first two to four days of their infection
• not sharing food, eating utensils, or cups
• avoiding crowded places where cold viruses can spread
• keeping hands away from the face
• avoiding cigarette smoke
• taking Echinacea; 250 mg up to four times daily for three weeks on, one week off
• taking astragalus; 250 mg to 500 mg daily.
• taking a multivitamin with zinc
• taking vitamin C ; 500 mg
• taking Anas barbariae hepatis ; one dose weekly

In 2002, researchers discovered that transmission of the rhinovirus may be prevented through the use of anti-septic skin cleansers containing salicylic acid or pyroglutamic acid. The cleansers have properties that can kill the viruses and help prevent hand-to-hand transmission, but further research on their effectiveness remains to be done.

Resources

BOOKS

Castleman, Michael. "Cold and Flu Therapy." In Nature's Cures. Emmaus, PA: Rodale Press, 1996.

Silverstein Alvin, et al. Common Cold and Flu (Diseases and People). Springfield, MA: Enslow Publishers, 1996.

Ying, Zhou Zhong, and Jin Hui De. "Exterior Invasion." In Clinical Manual of Chinese Herbal Medicine and Acupuncture. New York: Churchill Livingston, 1997.

PERIODICALS

"Antispetic Skin Cleansers May Prevent Rhinovirus Transmission."Clinical Infectious Diseases (February 1, 2002): ii.

Bourassa, Nicole. "Larch: This Immune Booster Fights Tenacious Colds and Ear Infections."Natural Health (March 2002): 35.

Elkins, Rita. "Combat Colds and Flu."Let's Live 68 (January 2000): 81+.

Jackson, Jeffrey L., Cecily Peterson, and Emil Lesho. "A Meta-Analysis of Zinc Salts Lozenges and the Common Cold." Archives of Internal Medicine 157 (1997): 2373–2376.

Le Page, Michael. "Eat to Treat: The Maxim "Feed a Cold, Starve a Fever" May be Right After All."New Scientist (January 19, 2002): 15.

Marshall, Shaun. "Zinc Gluconate and the Common Cold: Review of Randomized Controlled Trials."Canadian Family Physician 44 (1998): 1037–1042.

Mayo Health Clinic. "Zinc: A Weapon Against the Common Cold?"Mayo Health Oasis http://www.mayohealth.org/mayo/9709/htm/zinc.htm. (9 September 1997).

Belinda Rowland

Teresa G. Odle

Common cold

Definition

The common cold, also called a rhinovirus or coronavirus infection, is a viral infection of the upper respiratory system, including the nose, throat, sinuses, eustachian tubes, trachea, larynx, and bronchial tubes. Over 200 different viruses can cause a cold. Almost all colds clear up in less than two weeks without complications.

Description

Cold season in the United States begins in early autumn and extends through early spring. Although it is not true that getting wet or being in a draft causes a cold (a person has to come in contact with the virus to catch a cold), certain conditions may lead to increased susceptibility. These include:

• fatigue and overwork
• emotional stress
• poor nutrition
• smoking
• living or working in crowded conditions

Although most colds resolve on their own without complications, they are a leading cause of visits to the doctor and of time lost from work and school. Treating symptoms of the common cold has given rise in the United States to a multi-million dollar industry in over-the-counter medications.

Colds make the upper respiratory system less resistant to bacterial infection. Secondary bacterial infection may lead to middle ear infection (otitis media), bronchitis, pneumonia , sinus infection, or strep throat . People with chronic lung disease, asthma , diabetes, or a weakened immune system are more likely to develop these complications.

Transmission

People with colds are contagious during the first two to four days of the infection. Colds pass from person to person in several ways. When an infected person coughs, sneezes, or speaks, tiny fluid droplets containing the virus are expelled. If these are breathed in by other people, the virus may establish itself in their noses and airways.

Colds may also be passed through direct contact. If a person with a cold touches his runny nose or watery eyes, then shakes hands with another person, some of the virus is transferred to the uninfected person. If that person then touches his mouth, nose, or eyes, the virus is transferred to an environment where it can reproduce and cause a cold.

In addition, cold viruses can be spread through inanimate objects (door knobs, telephones, toys ) that become contaminated with the virus. This is a common method of transmission in childcare centers. If a child with a cold touches his runny nose, then plays with a toy, some of the virus may be transferred to the toy. When another child plays with the toy a short time later, he may pick up some of the virus on his hands. The second child then touches his contaminated hands to his eyes, nose, or mouth and transfers some of the cold virus to himself.

Demographics

Colds are the most common illness to strike any part of the body, with over one billion colds in the United States each year. Anyone can get a cold, although pre-school and grade school children catch them more frequently than adolescents and adults. Children average six to ten colds a year. In families with children in school, the number can be as high as 12 per year. Women, especially those aged 20 to 30 years old, have more colds than men, possibly because of their closer contact with children. Individuals older than 60 usually have fewer than one cold per year. Repeated exposure to viruses causing colds creates partial immunity.

Causes and symptoms

Colds are caused by more than 200 different viruses. The most common groups are rhinoviruses and coronaviruses. Different groups of viruses are more infectious at different seasons of the year, but knowing the exact virus causing the cold is not important in treatment.

Once acquired, the cold virus attaches itself to the lining of the nasal passages and sinuses. This condition causes the infected cells to release a chemical called histamine. Histamine increases the blood flow to the infected cells, causing swelling, congestion, and increased mucus production. Within one to three days the infected person begins to show cold symptoms.

The first cold symptoms are a tickle in the throat, runny nose, and sneezing. The initial discharge from the nose is clear and thin. Later it changes to a thick yellow or greenish discharge. Most adults do not develop a fever when they catch a cold. Young children may develop a low fever of up to 102°F (38.9°C).

In addition to a runny nose and fever, signs of a cold include coughing, sneezing, nasal congestion, headache , muscle ache, chills, sore throat , hoarseness, watery eyes, tiredness, and lack of appetite. The cough that accompanies a cold is usually intermittent and dry.

Most people begin to feel better four to five days after their cold symptoms become noticeable. All symptoms are generally gone within ten days, except for a dry cough that may linger for up to three weeks.

When to call the doctor

Colds make people more susceptible to bacterial infections such as strep throat, middle ear infections, and sinus infections. People who have colds that do not begin to improve within a week or who experience chest pain , fever for more than a few days, difficulty breathing, bluish lips or fingernails, a cough that brings up greenish-yellow or grayish sputum, skin rash, swollen glands, or whitish spots on the tonsils or throat should consult a doctor to see to determine if they have acquired a secondary bacterial infection that needs to be treated with an antibiotic.

Children who have chronic lung disease, diabetes, or a weakened immune system—either from diseases such as AIDS or leukemia or as the result of medications, (corticosteroids, chemotherapy drugs)—should consult their doctor if they get a cold. Children with these health problems are more likely to get a secondary infection. For children with asthma, colds are a common trigger of asthma symptoms.

Diagnosis

Colds are diagnosed by observing a child's symptoms. There are no laboratory tests as of 2004 for detecting the cold virus. However, a doctor may do a throat culture or blood test to rule out a secondary infection.

Influenza is sometimes confused with a cold, but flu causes much more severe symptoms, as well as a fever. Allergies to molds or pollens also can make the nose run. Allergies are usually more persistent than the common cold. An allergist can do tests to determine if the cold-like symptoms are being caused by an allergic reaction. Also, some people get a runny nose when they go outside in winter and breathe cold air. This type of runny nose is not a symptom of a cold.

Treatment

There are no medicines that will cure the common cold. Given time, the body's immune system makes antibodies to fight the infection, and the cold is resolved without any intervention. Antibiotics are useless against a cold. However, there are many products that have been developed by pharmaceutical companies in the United States designed to relieve cold symptoms. These products usually contain antihistamines, decongestants , and/or pain relievers.

Antihistamines block the action of the chemical histamine that is produced when the cold virus invades the cells lining the nasal passages. Histamine increases blood flow and causes the cells to swell. Antihistamines are taken to relieve the symptoms of sneezing, runny nose, itchy eyes, and congestion. Side effects are dry mouth and drowsiness, especially with the first few doses. Antihistamines should not be taken by people who are driving or operating dangerous equipment. Some people have allergic reactions to antihistamines. Common over-the-counter antihistamines are Chlor-Trimeton, Dimetapp, Tavist, and Actifed. The generic name for two common antihistamines are chlorpheniramine and diphenhydramine.

Decongestants work to constrict the blood flow to the vessels in the nose. They can shrink the tissue, reduce congestion, and open inflamed nasal passages, making breathing easier. Decongestants can make people feel jittery or keep them from sleeping. They should not be used by people with heart disease, high blood pressure, or glaucoma. Some common decongestants are Neo-Synepherine, Novafed, and Sudafed. The generic names of common decongestants include phenylephrine, phenylpropanolamine, pseudoephedrine, and in nasal sprays naphazoline, oxymetazoline, and xylometazoline.

Many over-the-counter medications are combinations of both antihistamines and decongestants; an ache and pain reliever, such as acetaminophen (Datril, Tylenol, Panadol) or ibuprofen (Advil, Nuprin, Motrin, Medipren); and a cough suppressant (dextromethorphan). Common combination medications include Tylenol Cold and Flu, Triaminic, Sudafed Plus, and Tavist D. Aspirin should not be given to children with a cold because of its association with a risk of Reye's syndrome .

Nasal sprays and nose drops are other products promoted for reducing nasal congestion. These usually contain a decongestant, but the decongestant in the nasal preparations can act more quickly and strongly than ones found in pills or liquids because it is applied directly in the nose. Congestion returns after a few hours. People can become dependent on nasal sprays and nose drops. If used for a long time, users may suffer withdrawal symptoms when these products are discontinued. The label on the preparation should be checked for recommendations on length and frequency of use, since nasal sprays and nose drops should not be used for more than a few days.

People react differently to different cold medications and may find some more helpful than others. A medication may be effective initially then lose some of its effectiveness. Children sometimes react differently than adults. Over-the-counter cold remedies should not be given to infants without consulting a doctor first.

Care should be taken not to exceed the recommended dosages, especially when combination medications or nasal sprays are taken. These medicines do not shorten or cure a cold; at best they can only help a person feel more comfortable.

In addition to the optional use of over-the-counter cold remedies, there are some self-care steps that can be taken to ease discomfort. These include:

• drinking plenty of fluids, but avoiding acidic juices, which may irritate the throat
• gargling with warm salt water—made by adding one teaspoon of salt to 8 oz of water—for a sore throat
• avoiding second-hand smoke
• getting plenty of rest
• using a cool-mist room humidifier to ease congestion and sore throat
• rubbing Vaseline or other lubricant under the nose to prevent irritation from frequent nose blowing
• for babies too young to blow their noses, the mucus should be suctioned gently with an infant nasal aspirator (It may be necessary to soften the mucus first with a few drops of salt water.)

Alternative treatment

Alternative practitioners emphasize that people get colds because their immune systems are weak. They point out that everyone is exposed to cold viruses, but not everyone gets every cold. The difference seems to be in the ability of the immune system to fight infection. Prevention focuses on strengthening the immune system by eating a healthy diet low in sugars and high in fresh fruits and vegetables, practicing meditation or using other means to reduce stress, and getting regular moderate exercise .

Once cold symptoms appear, some naturopathic practitioners believe the symptoms should be allowed to run their course without interference. Others suggest the following:

• Aromatherapy remedy: Inhaling a steaming mixture of lemon oil, thyme oil, eucalyptus, and tea tree oil (Melaleuca spp.).
• Ayurvedic medicinal remedy: Gargling with a mixture of water, salt, and turmeric powder or astringents, such as alum, sumac, sage, and bayberry to ease a sore throat.
• Herbal remedies: Taking coneflower (Echinacea spp.) or goldenseal (Hydrastis canadensis ). Other useful herbs to reduce symptoms are yarrow (Achillea millefolium ), eyebright (Euphrasia officinalis ), garlic (Allium sativum ), and onions (Allium cepa ).
• Homeopathic remedies: Microdoses of Viscue album, Natrum muriaticum, Allium cepa, or Nux vomica.
• Chinese traditional medicinal remedies: Taking yin chiao (sometimes transliterated as yinquiao) tablets that contain honeysuckle and forsythia when symptoms appear as well as using natural herb loquat syrup for cough and sinus congestion.
• Nutritional therapy: The use of zinc lozenges every two hours along with high doses of vitamin C as well as eliminating dairy products for the duration of the cold.

Prognosis

Given time, the body produces antibodies to cure itself of a cold. Most colds last a week to ten days. Most people start feeling better within four or five days. Occasionally a cold will lead to a secondary bacterial infection that causes strep throat, bronchitis, pneumonia, sinus infection, or a middle ear infection. These conditions usually clear up rapidly when treated with an antibiotic.

Prevention

It is not possible to prevent colds because the viruses that cause colds are common and highly infectious. However, there are some steps individuals can take to reduce their spread. These include:

• washing hands well and frequently, especially after touching the nose or before handling food
• using instant hand sanitizers, which are antiseptics and not antibiotics
• covering the mouth and nose when sneezing
• disposing of used tissues properly
• avoiding close contact with someone who has a cold during the first two to four days of their infection
• not sharing food, eating utensils, or cups
• using paper towels rather than shared cloth towels
• avoiding crowded places where cold germs can spread
• eating a healthy diet and getting adequate sleep
• using a daycare facility with six or fewer children, to dramatically reduce germ contact

Parental concerns

The over-use of antibiotics has led to the development of antibiotic-resistant stains of bacteria. For these bacteria, antibiotics may be ineffective. Therefore, parents should not press the doctor to prescribe antibiotics when their children only have a cold.

Also, a parent should not give a child aspirin during a cold, because aspirin has been linked to the development of Reye's syndrome in children recovering from viral illnesses, especially influenza (flu) or chickenpox . Reye's syndrome can lead to permanent brain damage or death.

KEY TERMS

Bronchial tubes —The major airways to the lungs and their main branches.

Coronavirus —A genus of viruses that cause respiratory diseases and gastroenteritis.

Corticosteroids —A group of hormones produced naturally by the adrenal gland or manufactured synthetically. They are often used to treat inflammation. Examples include cortisone and prednisone.

Eustachian tube —A thin tube between the middle ear and the pharnyx. Its purpose is to equalize pressure on either side of the ear drum.

Reye's syndrome —A serious, life-threatening illness in children, usually developing after a bout of flu or chickenpox, and often associated with the use of aspirin. Symptoms include uncontrollable vomiting, often with lethargy, memory loss, disorientation, or delirium. Swelling of the brain may cause seizures, coma, and in severe cases, death.

Rhinovirus —A group of small RNA viruses that infects the upper respiratory system and causes the common cold.

Resources

BOOKS

Royston, Angela. Colds (It's Catching) Oxford, UK: Heinemann Library, 2001.

Silverstein, Alvin. Common Colds. Minneapolis, MN: Sagebrush Corp., 2001.

Judith Sims Tish Davidson, A.M.

Common Cold

Definition

The common cold is a viral infection of the upper respiratory system, including the nose, throat, sinuses, eustachian tubes, trachea, larynx, and bronchial tubes. Although more than 200 different viruses can cause a cold, 30-50% are caused by a group known as rhinoviruses. Almost all colds clear up in less than two weeks without complications.

Description

Colds, sometimes called rhinovirus or coronavirus infections, are the most common illness to strike any part of the body. It is estimated that the average person has more than 50 colds during a lifetime. Anyone can get a cold, although pre-school and grade school children catch them more frequently than adolescents and adults. Repeated exposure to viruses causing colds creates partial immunity.

Although most colds resolve on their own without complications, they are a leading cause of visits to the doctor and of time lost from work and school. Treating symptoms of the common cold has given rise to a multi-million dollar industry in over-the-counter medications.

Cold season in the United States begins in early autumn and extends through early spring. Although it is not true that getting wet or being in a draft causes a cold (a person has to come in contact with the virus to catch a cold), certain conditions may lead to increased susceptibility. These include:

• fatigue and overwork
• emotional stress
• poor nutrition
• smoking
• living or working in crowded conditions

Colds make the upper respiratory system less resistant to bacterial infection. Secondary bacterial infection may lead to middle ear infection, bronchitis, pneumonia, sinus infection, or strep throat. People with chronic lung disease, asthma, diabetes, or a weakened immune system are more likely to develop these complications.

Causes and symptoms

Colds are caused by more than 200 different viruses. The most common groups are rhinoviruses and coronaviruses. Different groups of viruses are more infectious at different seasons of the year, but knowing the exact virus causing the cold is not important in treatment.

People with colds are contagious during the first two to four days of the infection. Colds pass from person to person in several ways. When an infected person coughs, sneezes, or speaks, tiny fluid droplets containing the virus are expelled. If these are breathed in by other people, the virus may establish itself in their noses and airways.

Colds may also be passed through direct contact. If a person with a cold touches his runny nose or watery eyes, then shakes hands with another person some of the virus is transferred to the uninfected person. If that person then touches his mouth, nose, or eyes, the virus is transferred to an environment where it can reproduce and cause a cold.

Finally, cold viruses can be spread through inanimate objects (door knobs, telephones, toys) that become contaminated with the virus. This is a common method of transmission in child care centers. If a child with a cold touches her runny nose, then plays with a toy, some of the virus may be transferred to the toy. When another child plays with the toy a short time later, he may pick up some of the virus on his hands. The second child then touches his contaminated hands to his eyes, nose, or mouth and transfers some of the cold virus to himself.

Once acquired, the cold virus attaches itself to the lining of the nasal passages and sinuses. This causes the infected cells to release a chemical called histamine. Histamine increases the blood flow to the infected cells, causing swelling, congestion, and increased mucus production. Within one to three days the infected person begins to show cold symptoms.

The first cold symptoms are a tickle in the throat, runny nose, and sneezing. The initial discharge from the nose is clear and thin. Later it changes to a thick yellow or greenish discharge. Most adults do not develop a fever when they catch a cold. Young children may develop a low fever of up to 102°F (38.9°C).

In addition to a runny nose and fever, signs of a cold include coughing, sneezing, nasal congestion, headache, muscle ache, chills, sore throat, hoarseness, watery eyes, tiredness, and lack of appetite. The cough that accompanies a cold is usually intermittent and dry.

Most people begin to feel better four to five days after their cold symptoms become noticeable. All symptoms are generally gone within ten days, except for a dry cough that may linger for up to three weeks.

Colds make people more susceptible to bacterial infections such as strep throat, middle ear infections, and sinus infections. A person whose cold does not begin to improve within a week; or who experiences chest pain, fever for more than a few days, difficulty breathing, bluish lips or fingernails, a cough that brings up greenish-yellow or grayish sputum, skin rash, swollen glands, or whitish spots on the tonsils or throat should consult a doctor to see if he or she has acquired a secondary bacterial infection that needs to be treated with an antibiotic.

People who have emphysema, chronic lung disease, diabetes, or a weakened immune system—either from diseases such as AIDS or leukemia, or as the result of medications, (corticosteroids, chemotherapy drugs)—should consult their doctor if they get a cold. People with these health problems are more likely to get a secondary infection.

Diagnosis

Colds are diagnosed by observing a person's symptoms. There are no laboratory tests readily available to detect the cold virus. However, a doctor may do a throat culture or blood test to rule out a secondary infection.

Influenza is sometimes confused with a cold, but flu causes much more severe symptoms and generally a fever. Allergies to molds or pollens also can make the nose run. Allergies are usually more persistent than the common cold. An allergist can do tests to determine if the cold-like symptoms are being caused by an allergic reaction. Also, some people get a runny nose when they go outside in winter and breathe cold air. This type of runny nose is not a symptom of a cold.

Treatment

There are no medicines that will cure the common cold. Given time, the body's immune system will make antibodies to fight the infection, and the cold will be resolved without any intervention. Antibiotics are useless against a cold. However, a great deal of money is spent by pharmaceutical companies in the United States promoting products designed to relieve cold symptoms. These products usually contain antihistamines, decongestants, and/or pain relievers.

Antihistamines block the action of the chemical histamine that is produced when the cold virus invades the cells lining the nasal passages. Histamine increases blood flow and causes the cells to swell. Antihistamines are taken to relieve the symptoms of sneezing, runny nose, itchy eyes, and congestion. Side effects are dry mouth and drowsiness, especially with the first few doses. Antihistamines should not be taken by people who are driving or operating dangerous equipment. Some people have allergic reactions to antihistamines. Common over-the-counter antihistamines include Chlor-Trimeton, Dimetapp, Tavist, and Actifed. The generic name for two common antihistamines are chlorpheniramine and diphenhydramine.

Decongestants work to constrict the blood flow to the vessels in the nose. This can shrink the tissue, reduce congestion, and open inflamed nasal passages, making breathing easier. Decongestants can make people feel jittery or keep them from sleeping. They should not be used by people with heart disease, high blood pressure, or glaucoma. Some common decongestants are Neo-Synepherine, Novafed, and Sudafed. The generic names of common decongestants include phenylephrine, phenylpropanolamine, pseudoephedrine, and in nasal sprays naphazoline, oxymetazoline and xylometazoline.

Many over-the-counter medications are combinations of both antihistamines and decongestants; an ache and pain reliever, such as acetaminophen (Datril, Tylenol, Panadol) or ibuprofen (Advil, Nuprin, Motrin, Medipren); and a cough suppressant (dextromethorphan). Common combination medications include Tylenol Cold and Flu, Triaminic, Sudafed Plus, and Tavist D. Aspirin should not be given to children with a cold because of its association with a risk of Reye's syndrome, a serious disease.

Nasal sprays and nose drops are other products promoted for reducing nasal congestion. These usually contain a decongestant, but the decongestant can act more quickly and strongly than ones found in pills or liquids because it is applied directly in the nose. Congestion returns after a few hours.

People can become dependent on nasal sprays and nose drops. If used for a long time, users may suffer withdrawal symptoms when these products are discontinued. Nasal sprays and nose drops should not be used for more than a few days. The label lists recommendations on length and frequency of use.

Scientists reported in 2004 the possibility of a new oral drug for use in relieving common cold symptoms. Called pleconaril, it inhibited viral replication in at least 90% of rhinoviruses if taken within 24 hours of onset.

People react differently to different cold medications and may find some more helpful than others. A medication may be effective initially, then lose some of its effectiveness. Children sometimes react differently than adults. Over-the-counter cold remedies should not be given to infants without consulting a doctor first.

Care should be taken not to exceed the recommended dosages, especially when combination medications or nasal sprays are taken. Individuals should determine whether they wish to use any of these drugs. None of them shorten or cure a cold. At best they help a person feel more comfortable. People who are confused about the drugs in any over-the-counter cold remedies should ask their pharmacist for an explanation.

In addition to the optional use of over the counter cold remedies, there are some self-care steps that people can take to ease their discomfort. These include:

• drinking plenty of fluids, but avoiding acidic juices, which may irritate the throat
• gargling with warm salt water—made by adding one teaspoon of salt to 8 oz of water—for a sore throat
• not smoking
• getting plenty of rest
• using a cool-mist room humidifier to ease congestion and sore throat
• rubbing Vaseline or other lubricant under the nose to prevent irritation from frequent nose blowing
• for babies too young to blow their noses, the mucus should be suctioned gently with an infant nasal aspirator. It may be necessary to soften the mucus first with a few drops of salt water.

Alternative treatment

Alternative practitioners emphasize that people get colds because their immune systems are weak. They point out that everyone is exposed to cold viruses, but not everyone gets every cold. The difference seems to be in the ability of the immune system to fight infection. Prevention focuses on strengthening the immune system by eating a healthy diet low in sugars and high in fresh fruits and vegetables, practicing meditation to reduce stress, and getting regular moderate exercise.

Once cold symptoms appear, some naturopathic practitioners believe the symptoms should be allowed to run their course without interference. Others suggest the following:

• Inhaling a steaming mixture of lemon oil, thyme oil, eucalyptus, and tea tree oil (Melaleuca spp.). (Aromatherapy )
• Gargling with a mixture of water, salt, and turmeric powder or astringents such as alum, sumac, sage, and bayberry to ease a sore throat. (Ayurvedic medicine )
• Taking coneflower or goldenseal (Hydrastis canadensis ). Other useful herbs to reduce symptoms include yarrow (Achillea millefolium ), eyebright (Euphrasia officinalis ), garlic (Allium sativum ), and onions (Allium cepa ). (Herbal)
• Microdoses of Viscue album, Natrum muriaticum, Allium cepa, or Nux vomica. (Homeopathy)
• Taking yin chiao (sometimes transliterated as yinquiao) tablets that contain honeysuckle and forsythia when symptoms appear. Natural herb loquat syrup for cough and sinus congestion and Chinese ephedra (ma-huang ) for runny nose. (Chinese traditional medicine)
• The use of zinc lozenges every two hours along with high doses of vitamin C is suggested. Some practitioners also suggest eliminating dairy products for the duration of the cold. (Nutritional therapy).

The use of zinc lozenges may be moving toward acceptance by practitioners of traditional medicine. In 1996 the Cleveland Clinic tested zinc gluconate lozenges and found using zinc in the first 24 hours after cold symptoms occurred shortened the duration of symptoms. The mechanism by which zinc worked was not clear, but additional studies are underway.

At one time, the herb (Echinacea spp.) was touted as a remedy to relieve cold symptoms. However, a study published in 2004 reported that the herb failed to relieve cold symptoms in 400 children taking it and caused skin rashes in some children.

Prognosis

Given time, the body will make antibodies to cure itself of a cold. Most colds last a week to 10 days. Most people start feeling better within four or five days. Occasionally a cold will lead to a secondary bacterial infection that causes strep throat, bronchitis, pneumonia, sinus infection, or a middle ear infection. These conditions usually clear up rapidly when treated with an antibiotic.

Prevention

It is not possible to prevent colds because the viruses that cause colds are common and highly infectious. However, there are some steps individuals can take to reduce their spread. These include:

• washing hands well and frequently, especially after touching the nose or before handling food
• covering the mouth and nose when sneezing
• disposing of used tissues properly

• avoiding close contact with someone who has a cold during the first two to four days of their infection
• not sharing food, eating utensils, or cups with anyone
• avoiding crowded places where cold germs can spread
• eating a healthy diet and getting adequate sleep

Resources

PERIODICALS

"Study: Echinacea Is Ineffective." Chain Drug Review February 16, 2004: 25.

Zepf, Bill. "Pleconaril for Treatment of the Common Cold?" American Family Physician February 1, 2004: 703.

KEY TERMS

Bronchial tubes— The major airways to the lungs and their main branches.

Coronavirus— a genus of viruses that cause respiratory disease and gastroenteritis.

Corticosteroids— A group of hormones produced naturally by the adrenal gland or manufactured synthetically. They are often used to treat inflammation. Examples include cortisone and prednisone.

Eustachian tube— A thin tube between the middle ear and the pharynx. Its purpose is to equalize pressure on either side of the ear drum.

Rhinovirus— A virus that infects the upper respiratory system and causes the common cold.

Cold, common

Dedicated researchers have searched for a cure or even an effective treatment for the common cold (rhinitis) for years. Discovering or constructing the agent that will be universally lethal to all the cold-causing viruses has been fruitless. A drug that will kill only one or two of the viruses would be of little use since the patient would not know which of the viruses was the one that brought on his cold.

The common cold differs in several ways from influenza or the flu. Cold symptoms develop gradually and are relatively mild. The flu has a sudden onset and has more serious symptoms the usually put the sufferer to bed, and the flu lasts about twice as long as the cold. Also influenza can be fatal, especially to elderly persons, though the number of influenza viruses is more limited than the number of cold viruses, and vaccines are available against certain types of flu.

Rhinoviruses, adenoviruses , influenza viruses, parainfluenza viruses, syncytial viruses, echoviruses, and coxsackie viruses—all have been implicated as the agents that cause the runny nose, cough, sore throat, and sneezing that advertise that you have a cold. More than 200 viruses, each with its own favored method of being passed from one person to another, its own gestation period, each different from the others, wait patiently to invade the mucous membranes that line the nose of the next cold victim.

Passing the cold-causing virus from one person to the next can be done by sneezing onto the person, by shaking hands, or by an object handled by the infected person and picked up by the next victim. Oddly, direct contact with the infected person, as in kissing, is not an efficient way for the virus to spread. Only in about 10% of such contacts does the uninfected person get the virus. Walking around in a cold rain will not cause a cold. Viruses like warm, moist surroundings, so they thrive indoors in winter. Colds are easily passed in the winter, because people spend more time indoors then than they do outdoors. However, being outdoors in cold weather can dehydrate the mucous membranes in the nose and make them more susceptible to infection by a rhinovirus.

In addition, cold-causing viruses mutate with regularity. Each time it is passed from one person to the next, the virus changes slightly, so it is not the virus the first person had. Viruses are obligate parasites , meaning that they can carry out their functions only when they invade another living cell.

The virus has a tough envelope surrounding its nucleic acids, the genetic material for any living thing. Once it invades the body, the virus waits to be placed in the location in which it can function best. Once there, it attaches to a cell by means of receptor areas on its envelope and on the cell membrane. The viral nucleic acid then is inserted into the cell nucleus and it takes over the functions of the nucleus, telling it to reproduce viruses.

Taking regular doses of vitamin C will not ward off a cold. However, high doses of vitamin C once a person has a cold may help to alleviate symptoms and reduce discomfort. Over-the-counter drugs to treat colds treat only the symptoms. They may dry up the patient's runny nose, but after a few days the nose will compensate and overcome the effects of the medication and begin to drip again. The runny nose is from the loss of plasma from the blood vessels in the nose. Some researchers assert the nose drip is a defensive mechanism to prevent the invasion of other viruses. Antibiotics such as penicillin are useless against the cold because they do not affect viruses.

Scientists agree that the old wives' remedy of chicken soup can help the cold victim, but so can any other hot liquid. The steam and heat produced by soup or tea helps to liquefy the mucus in the sinus cavities, allowing them to drain, reducing the pressure and making the patient feel better. The remedy is temporary and has no effect on the virus. Colds are usually self-limiting, and recovery usually occurs within a week.

See also Cold, viruses; Infection and resistance; Viruses and responses to viral infection

common cold acute viral infection of the mucous membranes of the nose and throat, often involving the sinuses. The typical sore throat, sneezing, and fatigue may be accompanied by body aches, headache, low fever, and chills. The congested and discharging mucous membrane may become a fertile ground for a secondary bacterial invasion that can spread to the larynx, bronchi, lungs, or ears. Uncomplicated infections usually last from three to ten days.

The cold is the most common human ailment. Most adult Americans suffer from one to four colds per year, but children ages one to five—who are the most susceptible—typically may contract as many as eight. Colds are spread by respiratory droplets or by contaminated hands or objects. Although the incidence of colds is higher in winter, exposure to chilling or dampness is considered to be of little significance.

Any one of up to 200 viruses (such as the rhinoviruses, coronaviruses, or respiratory syncytial virus [RSV]) can cause colds, to which it seems almost no one is immune. Infection with a viral strain confers only temporary immunity to that strain. Colds in infants and young children caused by RSV can progress to pneumonia and other complications, especially in those under a year old who were born prematurely or have chronic lung disease; RSV causes an estimated 4,500 deaths yearly in these groups in the United States.

Treatment for the common cold aims at relieving symptoms and keeping the body well-rested, -fed, and -hydrated. Because of the growing problem of drug resistance, doctors are discouraged from prescribing antibiotics (which do not affect viruses) for colds unless secondary bacterial infection makes them necessary. There is some evidence that zinc preparations, when taken within 24 hours of the first cold symptoms, can shorten the duration and moderate the symptoms of an infection, but there is no convincing evidence that vitamin C megadoses can prevent the common cold.

Researchers have reported reduction or prevention of cold symptoms in human tests of an experimental drug against rhinoviruses, which cause nearly half of all colds. The drug acts by imitating a molecule in the body called ICAM-1, to which the rhinovirus attaches to produce colds. As rhinoviruses attach to the decoy molecules instead, the likelihood or severity of infection is decreased.

COMMON COLD

DEFINITION

The common cold is a viral infection of the upper respiratory system. The upper respiratory system includes the nose, throat, sinuses, eustachian (pronounced yoo-STA-shuhn) tubes, trachea (pronounced TRAY-kee-uh), larynx, and bronchial tubes. More than two hundred different viruses can cause a cold. A group of viruses known as the rhinoviruses, however, causes about 30 to 50 percent of all colds. Almost all colds clear up in less than two weeks without complications.

Common Cold: Words to Know

Bronchial tubes:

The major airways that lead to the lungs.

Coronavirus:

A type of virus that can cause the common cold.

Eustachian tube:

A thin tube between the middle ear and the pharynx at the back of the mouth.

Rhinovirus:

A type of virus that can cause the common cold.

DESCRIPTION

Colds are sometimes called rhinovirus or coronavirus (pronounced kuh-RO-nuh-vie-russ) infections. They are the most common infections to affect any part of the body. Experts estimate that the average person has more than fifty colds during a lifetime. Anyone can catch a cold. The disease is most common, however, among children. Repeated exposure to the viruses that cause colds helps to prevent against future occurrences of the disease.

An individual who has a cold usually recovers without special treatment. Still, colds are the leading cause of visits to doctors and of time lost from work and school. Americans spend millions of dollars each year for over-the-counter medications designed to treat cold symptoms.

Cold season in the United States begins in early fall and extends through early spring. Some people think, incorrectly, that becoming cold or wet can cause a cold. Only exposure to a cold virus can bring on the disease. Some factors can, however, increase the likelihood of catching a cold. These include:

• Fatigue and overwork
• Emotional stress
• Poor nutrition
• Smoking
• Living or working in crowded conditions

Colds make the upper respiratory system less resistant to bacterial infections. Some of these infections include middle ear infection, bronchitis (see bronchitis entry), pneumonia (see pneumonia entry), sinus infection, and strep throat (see strep throat entry).

CAUSES

Colds are caused by more than two hundred different viruses. The most common groups of viruses are rhinoviruses and coronaviruses. Knowing which virus has caused a cold is not important because treatment does not depend on the type of virus.

People with colds are contagious (can pass on the virus) during the first two to four days of infection. The virus can be passed in various ways. When an infected person coughs, sneezes, or speaks, for example, fluid droplets containing the virus are discharged. People nearby may breathe in the droplets and may then become infected.

Cold viruses can be passed from person to person through direct contact, such as shaking hands. The viruses can also be spread through nonliving objects, such as doorknobs, telephones, and toys. This method of transmission is common in day-care centers. A child with a cold may transfer the cold virus to a toy with which he or she is playing. When another child picks up the same toy, he or she may also pick up the cold virus.

SYMPTOMS

Once acquired, the cold virus attaches itself to the lining of the nasal (nose) passages and sinuses. Infected cells begin to give off a chemical called histamine (pronounced HISS-tuh-meen). Histamine causes swelling, congestion (stuffiness), and increased production of mucus. One to three days after infection, a person begins to feel cold symptoms caused by these changes.

The first of these symptoms include a tickle in the throat, runny nose, and sneezing. Initially, discharge from the nose is clear and thin. Later it changes to a thick, yellow or greenish discharge. Young children often develop a fever of up to 102°F (39°C). Adults are less likely to have a fever with a cold.

Other signs of a cold are coughing, sneezing, nasal congestion, headache, muscle ache, chills, sore throat, hoarseness, watery eyes, tiredness, and lack of appetite. The cough that accompanies a cold is usually intermittent (it comes and goes) and dry.

Most people begin to feel better four or five days after cold symptoms first appear. All symptoms are usually gone within ten days. Sometimes a dry cough can linger for up to three weeks.

Colds make people more open to bacterial infections, such as strep throat, middle ear infection, and sinus infections. Some warning signs of a bacterial infection include chest pain, fever for more than a few days, difficulty breathing, bluish lips or fingernails, skin rash, and swollen glands. A person with these symptoms should see a doctor for possible treatment.

For some people, colds can cause more serious health problems. Anyone with complications of the respiratory (breathing) system, such as emphysema (pronounced em-fi-SEE-muh; see emphysema entry), chronic lung disease, diabetes (see diabetes entry), or with a weakened immune system (as caused by AIDS) should see a doctor if they catch a cold.

DIAGNOSIS

Colds are diagnosed by observing a person's symptoms. There are no laboratory tests to detect the cold virus. However, doctors sometimes do a throat culture or blood test to make sure the patient's symptoms are not caused by some other disease.

Influenza (or the flu; see influenza entry) is sometimes confused with the common cold. But the flu is accompanied by more severe symptoms, including a fever. Allergies (see allergies entry) often cause cold-like symptoms also. But allergy symptoms last much longer than cold symptoms. Exposure to cold air can also sometimes cause cold-like symptoms. However, these symptoms do not indicate the presence of a viral infection.

TREATMENT

There are no medicines that will cure the common cold. Given time, the body's immune system will make antibodies to fight the infection and the cold will get better on its own. Antibiotics have no effect on colds because they do not kill viruses.

A very large number of medications are available for the treatment of cold symptoms. These include antihistamines, decongestants, and pain relievers. Antihistamines block the action of histamine. They relieve sneezing, runny nose, itchy eyes, and congestion. Side effects include a dry mouth and drowsiness. For this reason, antihistamines should not be taken by people who must drive or operate heavy machinery. Some common trade name antihistamines include Chlor-Trimeton, Dimetapp, Tavist, and Actifed. The generic (family) name for these drugs are chlorpheniramine (pronounced KLOR-fen-eruh-meen) and diphenhydramine (pronounced DIE-fen-HI-druh-meen).

Decongestants reduce blood flow and shrink tissues in the nose and make it easier to breathe. A side effect is nervousness and an inability to sleep. People with heart disease, high blood pressure, or glaucoma (an eye disorder; see glaucoma entry) should not use decongestants. Some common trade name decongestants are Neo-Synepherine, Novafed, and Sudafed. The generic names of common decongestants include phenylephrine (pronounced fenuhl-EF-reen), phenylpropanolamine (pronounced FEN-uhl-PRO-puh-NOL-uh-meen), pseudoephedrine (pronounced soo-doe-i-FED-run), and, in nasal sprays, naphazoline (pronounced nuh-FAZ-uh-leen), oxymetazoline (pronounced OX-si-muh-TAZ-uh-LEEN), and xylometazoline (pronounced ZIE-luh-met-uh-ZOE-leen).

Many over-the-counter medications are combinations of two or more drugs. They may contain an antihistamine, decongestant, pain reliever, and/or cough suppressant. Some common pain relievers include acetaminophen (pronounced uh-see-tuh-MIN-uh-fuhn, trade names Datril, Tylenol, Panadol) and ibuprofen (pronounced i-byoo-PRO-fuhn, trade names Advil, Nurpin, Motrin, Medipren). The most common cough suppressant is dextromethorphan (pronounced dek-struh-mi-THOR-fan). Medications that include combinations of drugs are Tylenol Cold and Flu, Triaminic, Sudafed Plus, and Tavist D. Aspirin should not be given to children with a cold. It may cause a serious condition known as Reye's syndrome (see Reye's syndrome entry).

Nasal sprays and nose drops can also help to reduce nasal congestion. These products are used to apply a decongestant directly to the nose. It can take effect and act more strongly, therefore, than decongestants in pills or liquids. One problem with nasal sprays and nose drops is that people may become dependent on them. Once an individual stops using the products, he or she may experience withdrawal symptoms. For that reason, nasal sprays and nose drops should not be used for more than a few days.

People react differently to various cold medications, therefore each person needs to find the medication that works best for himself or herself. The effectiveness of medications can also change over time. It should be especially noted that children sometimes react differently from adults to medications. Over-the-counter cold remedies should not be given to infants without first consulting a doctor.

Care should always be taken not to exceed the recommended dosage for any cold medication. People need to remember that cold remedies do not cure a cold or shorten its duration. They can only relieve symptoms. Pharmacists can often advise a cold-sufferer about the best medications to try.

Cold symptoms can also be relieved by some simple self-care steps. These include:

• Drinking plenty of fluids, but avoiding acidic juices (such as grapefruit juice) that may irritate the throat
• Gargling with warm salt water for a sore throat
• Not smoking
• Getting plenty of rest
• Using a cool-mist room humidifier to ease congestion and sore throat
• Rubbing a lubricant such as Vaseline under the nose to prevent irritation from frequent nose-blowing
• Removing mucus from the nose of infants who are too young to blow their noses. Infant nasal aspirators are available for this purpose

Alternative Treatment

The goal of many alternative treatments for colds is to strengthen a person's immune system. Alternative practitioners point out that everyone is exposed to cold viruses, but only some people get sick. Those people, they argue, are more likely to have weak immune systems. Practitioners recommend strengthening the immune system by eating a healthy diet low in sugars and high in fresh fruits and vegetables, practicing meditation to reduce stress, and getting regular, moderate exercise.

Some practitioners do not believe in treating the symptoms of a cold. They say the infection should be allowed to run its course naturally. Others suggest a variety of treatments, such as:

• Inhaling a steaming mixture of lemon oil, thyme oil, eucalyptus (pronounced yoo-kuh-LIP-tus), and tea tree oil
• Gargling with a mixture of water, salt and turmeric powder or other astringent (drying-out agent), such as alum, sumac, sage, and bayberry to ease a sore throat
• Taking one of a variety of herbs, such as echinacea. (ek-i-NAY-see-uh), goldenseal, yarrow, eyebright, garlic, or onion to relieve symptoms
• Taking one of a variety of Chinese herbal medicines, such as loquat syrup (for coughs and sinus congestion), or Chinese ephedra (for runny nose)
• Using zinc throat drops along with high doses of vitamin C

PROGNOSIS

Given time, the body's natural immune system will cure a cold. Most colds last a week to ten days. People usually start feeling better within four or five days. Colds sometimes lead to bacterial infections, including strep throat, bronchitis, pneumonia, sinus infection, or a middle ear infection. These conditions can be treated with antibiotics.

PREVENTION

Colds cannot be prevented because the viruses that cause them are very common and highly infectious. However, their spread can be reduced by some simple steps:

• Washing hands well and frequently, especially after touching the nose or before handling food.
• Covering the mouth and nose when sneezing.
• Disposing of used tissues properly.
• Avoiding close contact with anyone who has a cold during the first two to four days after infection.
• Not sharing food, eating utensils, or cups with anyone.
• Avoiding crowded places where cold germs can spread.
• Eating a healthy diet and getting adequate sleep.

FOR MORE INFORMATION

Books

Brody, Jane E. Jane Brody's Cold and Flu Fighter. New York: W. W. Norton & Company, 1995.

Burton Goldberg Group. "Colds and Flu," in Alternative Medicine: The Definitive Guide, edited by James Strohecker. Puyallup, WA: Future Medicine Publishing, 1994.

Inlander, Charles B., and Cynthia K. Moran. 77 Ways to Beat Colds and Flu. New York: Walker and Company, 1994.

Silverstein, Alvin, Virginia B. Silverstein, and Laura Silverstein Nunn. Common Colds. New York: Franklin Watts, Inc., 1999.

Silverstein, Alvin, et al. Common Cold and Flu. Springfield, NJ: Enslow Publishers, 1996.

Common Cold

What Is the Common Cold?

How Common Is the Common Cold?

Is the Common Cold Contagious?

What Happens to Someone Who Has a Cold?

Can Colds Be Prevented?

Resources

The “common cold” is a nickname for the commonly occurring viral infections of the upper respiratory tract*.

*respiratory tract

includes the nose, mouth, throat, and lungs. It is the pathway through which air and gases are transported down into the lungs and back out of the body.

KEYWORDS

for searching the Internet and other reference sources

Adenovirus

Coronavirus

Coxsackievirus

Echovirus

Influenza virus

Parainfluenza virus

Respiratory infection

Respiratory syncytial virus (RSV)

Rhinovirus

What Is the Common Cold?

More than 200 different viruses can cause colds. Rhinoviruses are responsible for up to a third of all upper respiratory infections. Other common viruses that lead to stuffy heads and runny noses include adenoviruses (ah-deh-no-VY-rus-sez), coronaviruses (ko-ro-nuh-VY-rus-sez), parainfluenza (pair-uh-in-floo-EN-zuh) viruses, respiratory syncytial (RES-puh-ruh-tor-e sin-SIH-she-ul) virus, coxsackieviruses (kok-SAHkee-vy-ruh-sez), echoviruses (EH-ko-vy-rus-sez), and influenza (in-flooEN-zuh) viruses (although influenza may also trigger more serious complications). Children get colds most frequently, in part because of their close contact with so many other children in daycare or school. Younger children also tend to cough without covering their mouths and do not regularly wash their hands.

In North America, young children in daycare may catch several (sometimes as many as 10 or more) colds each year. People tend to get fewer colds as they grow older because they develop immunity* to some of these viruses after being infected with them. For this reason, healthy adults average 2 to 4 colds a year, and those over age 60 tend to get even fewer (maybe 1 cold a year, or less).

*immunity

(ih-MYOON-uh-tee) is the condition of being protected against an infectious disease. Immunity often develops after a germ is introduced to the body. One type of immunity occurs when the body makes special protein molecules called antibodies to fight the disease-causing germ. The next time that germ enters the body, the antibodies quickly attack it, usually preventing the germ from causing disease.

Common Cold Myths

Colds are so common that everyone seems to have a theory on what brings them on and how to cure them. Just consider these common cold myths (and some myth-busting explanations):

MYTH: Running around in the cold and having a wet head or wet feet can bring on a cold.

REALITY: These two beliefs probably stem from the accurate observation that more colds seem to occur in the cold, wet weather that often accompanies winter months in the United States. In reality, though, it is not the cold or wet that brings on the illness. Colder weather drives people indoors, which means increased and closer contact with others and a higher risk for colds.

MYTH: “Feed a cold (and starve a fever).”

REALITY: A recent study found that eating might actually boost the power of the immune system against certain illnesses, such as long-lasting colds, whereas decreased food intake may stimulate immune system chemicals that keep fever away. Until more studies are done, many doctors continue to urge patients with colds to down warm soup and other light fare.

MYTH: Taking large doses of vitamin C prevents colds.

REALITY: Vitamin C may have other body-boosting benefits, but there is no scientific proof that it prevents the common cold. Although garlic (which may have antiviral properties) and chicken soup appear to have some beneficial effects, studies of other widely touted cold remedies such as echinacea (eh-kih-NAY-see-uh), a plant product, and zinc supplements have mostly yielded negative, inconsistent, or unconvincing results.

Cold season in the United States generally occurs during the fall and winter months, although people can get sick from viral respiratory infections year round. Many people believe the cold air is responsible for catching a cold, but there is no evidence that viruses spread more easily or that our immune system is weaker in the cold. However, winter is the time of year when more people stay inside, bringing them into closer contact with others and their germs.

How Common Is the Common Cold?

As many as a billion colds occur each year in the United States. The U.S. Centers for Disease Control and Prevention’s National Center for Health Statistics notes that on a yearly basis close to 22 million school days are lost due to illness from colds, and 45 million days are spent resting while recovering from colds.

Is the Common Cold Contagious?

Colds are very contagious. In general, they are most contagious during the first few days of illness, when symptoms like congestion (stuffy nose) and sneezing are starting. Cold viruses often spread through direct contact. Shaking the unwashed hand of someone with a cold (who has just touched his or her face) can easily spread the virus. When an infected person laughs, sneezes, or coughs, virus-packed droplets of moisture from the person’s mouth and nose can become suspended in the air, where they can be inhaled by others. Sometimes these drops of respiratory secretions land on a surface such as a kitchen or bathroom counter, where they can infect the next person who comes along and touches the surface.

What Happens to Someone Who Has a Cold?

Signs and symptoms

Cold symptoms usually appear within 2 to 3 days after the person becomes infected. They often include a runny or stuffy nose, watery eyes, coughing, mild muscle aches, tiredness, headache, low fever, and a scratchy, sore throat. Sneezing and coughing up mucus* are also common.

*mucus

(MYOO-kus) is a thick, slippery substance that lines the insides of many body parts.

Diagnosis

Doctors diagnose colds based on a history of symptoms and findings from a physical examination. Cultures* and other tests for the viruses are available but are not done in most situations. However, the doctor will want to distinguish a cold, caused by a virus, from bacterial infections of the sinuses or throat, such as strep throat.

*culture

(KUL-chur) is a test in which a sample of fluid or tissue from the body is placed in a dish containing material that supports the growth of certain organisms. Typically, within days the organisms will grow and can be identified.

This high-speed photograph captures a sneeze in action. Virus-packed droplets are expelled from the respiratory system and can spread widely to contaminate surfaces. Custom Medical Stock Photo, Inc.

Treatment

At the present time, there remains no true medical “cure” for the common cold. People who come down with colds can help themselves feel better by taking care of themselves at home until the infection goes away on its own. Bed rest helps tiredness, and inhaling mist in a steamy bathroom or running a humidifier in the bedroom to moisten dry air can relieve congestion and make it easier to breathe. Drinking plenty of clear or warm fluids may also reduce congestion, and tea with honey can soothe a scratchy throat. Over-the-counter medicines such as acetaminophen (uh-see-teh-MIH-noh-fen) can ease headaches and body aches and lower fever. Over-the-counter cold medicines may also help relieve symptoms. Symptoms of a cold can last up to a couple of weeks, but most people recover within a few days.

Because viruses cause colds, antibiotics are not useful in fighting these infections. Scientists are studying newer antiviral drugs that may be effective in fighting some cold-causing viruses (such as rhinoviruses). These medicines might change the treatment of colds in the future.

Complications

Sometimes colds can cause swelling and irritation in the nasal passages, eustachian tubes*, and airways leading to the lungs. Bacteria that invade the body can flourish in these areas, causing additional infections. This is why it is not uncommon for someone to develop sinusitis*, an ear infection (otitis, o-TIE-tis), or bronchitis at the end of a bad cold. For those with weaker immune systems, such as the very young, the elderly, or those with chronic illnesses, these secondary infections can lead to breathing problems from severe bronchitis or pneumonia, which may sometimes be life threatening. Colds also can trigger flare-ups or worsening of respiratory symptoms in people who have asthma.

*eustachian

(yoo-STAY-she-un) tubes are the tiny channels that connect and allow air to flow between the middle ears and the throat.

*sinusitis

(sy-nyoo-SY-tis) is an infection in the sinuses, which are hollow cavities in the facial bones near the nose.

Can Colds Be Prevented?

To lower the risk of catching (or spreading) a cold, experts advise that people wash their hands frequently and cover the mouth with a tissue when coughing or sneezing. Avoiding touching the eyes or nose as much as possible, regularly cleaning bathroom and kitchen surfaces to get rid of germs, and avoiding close, extended contact with anyone who has a cold are also helpful.

Researchers have explored the idea of a cold vaccine, but many different viruses can cause colds, making the development of a single, effective vaccine a great challenge.

See also

Bronchiolitis

Bronchitis, Infectious

Croup

Influenza

Laryngitis

Pneumonia

Sinusitis

Resources

Organization

U.S. National Institute of Allergy and Infectious Diseases (NIAID), Building 31, Room 7A-50, 31 Center Drive MSC 2520, Bethesda, MD 20892. The NIAID, part of the National Institutes of Health, posts information about viral infections that cause colds at its website. http://www.niaid.nih.gov

Website

KidsHealth.org. KidsHealth is a website created by the medical experts of the Nemours Foundation and is devoted to issues of children’s health. It contains articles on a variety of health topics, including the common cold.

http://www.KidsHealth.org

cold, common Minor disease of the upper respiratory tract caused by viral infection. Symptoms include inflammation of the nose, headache, sore throat and a cough. A cold usually disappears within a few days. Fever-reducing and pain-relieving drugs, as well as decongestants, may relieve symptoms; rest is recommended for heavy colds. Antibiotics may be prescribed where a bacterial infection is also present.