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.

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.

The rhinovirus (magnified 100,000 times) causes between 30 and 50 percent of all colds. (© 1991

CHSP

. Reproduced by permission of

Custom Medical Stock Photo

.)

A runny nose is one of the earliest warning signs of a cold. (Reproduced by permission of

Custom Medical Stock Photo

)

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.