A cold is an upper respiratory infection caused by a virus. They tend to occur most often in winter, although scientists aren't sure why. In the United States, adults usually have between two and four colds per year, and children have as many 10.

There is no foolproof way to prevent a cold – and no way to cure it – but you can treat the symptoms. Colds tend to last about a week, and can be accompanied by sore throat and cough. Unlike the flu, colds don't usually cause you to run a high fever (above 102 degrees Fahrenheit).

• Sneezing and runny nose from nasal congestion
• Sore throat
• Cough
• Hoarseness
• Low-grade fever (less than 102 degrees)
• Headache
• Fatigue

Colds are caused by more than 100 different viruses, although most colds are caused by rhinoviruses. You can get a cold by touching a person with a cold (for example, by shaking hands) and then touching your nose or eyes, or by touching a surface that a person with a cold has touched (such as telephone or keyboard). Colds are also transmitted through the air, when someone with a cold coughs or sneezes. Although you're more likely to get a cold in winter, exposure to cold outdoor air and fatigue do not increase your risk of getting sick (but stress may do so).

People more likely to get colds include:

• Children, especially those who attend day care or whose parents smoke
• Smokers and those exposed to second hand smoke
• Those exposed to industrial smoke, toxic fumes, or other air pollutants
• People with immune system disorders, such as HIV, AIDS, or cancer, or who take medications that suppress the immune system, such as corticosteroids
• People under a fair amount of stress

Most people treat colds without seeing a doctor. If you do see your doctor, the diagnosis will be made based on your symptoms and exam. He or she may take a throat culture to rule out strep throat. If you have an underlying lung condition, such as asthma or emphysema, you should let your doctor know right away when you get a cold.

Although anyone and everyone can get a cold, there are a few things that you can do that may help improve your immune system and make you less susceptible to getting colds:

• Wash your hands frequently
• Exercise regularly
• Eat a diet rich in fruits and vegetables and low in fat
• Get sufficient rest
• Minimize your stress and your reaction to stress. Yoga, tai chi, or other forms of relaxation may help.

With a cold, the goal of treatment is to improve your symptoms as quickly as possible. But even if you do nothing, they should go away within a week to 10 days. Antibiotics cannot help your cold. However, there are medications, herbs, supplements, and homeopathic remedies that may make you feel better while you have a cold.

Lifestyle

• Drink a lot of water to help loosen mucus.
• Rest to restore your energy and avoid complications such as bronchitis or pneumonia.
• Eat a diet rich in fresh fruits and vegetables. These foods provide lots of antioxidants (substances that may help boost your immune system), especially vitamins A and C.

Medications

A number of over-the-counter medications are available to help treat cold symptoms. Children under the age of six should not be given any over-the-counter cold or cough medicine.

Decongestants — help open your nasal passages so you can breathe easier. If decongestant nasal sprays or drops are used for more than three days, however, they can cause rebound congestion. Decongestants are often combined in cold medicines with antihistamines, cough suppressants, and pain relievers. People with heart disease, high blood pressure, diabetes, or glaucoma should not take decongestants. Popular brands of decongestants include Sudafed, Afrin, and Neo-Synephrine.

Antihistamines — can temporarily relieve a runny nose by drying up nasal secretions. Non-drowsy antihistamines available over the counter include loratadine (Claritin); others, such as fexofenadine (Allegra) and cetirizine (Zyrtec), are available by prescription.

Cough medicines — cough suppressants (for a dry cough) or expectorants (for a wet, productive cough that brings up mucous) are available over the counter and by prescription.

Pain relievers — such as aspirin, acetaminophen (Tylenol), and ibuprofen (Advil, Motrin) can be used for fever, body aches, and headaches. Children under the age of 16 should not take aspirin due to the risk of a rare but serious illness called Reye's syndrome.

Nutrition and Dietary Supplements

Because supplements may have side effects or interact with medications, they should be taken only under the supervision of a knowledgeable healthcare provider. Be sure to talk to your physician about any supplements you are taking or considering taking.

• Chicken soup — It’s about as traditional a remedy for a cold as you can find (at least in modern history). In fact, chicken soup and warm liquids (broth, tea) can help soothe a sore throat and loosen mucus, which in turn helps ease congestion from a cold.
• Probiotics (Lactobacillus) — So-called “good” bacteria or probiotics help prevent infections in the intestines, and there is preliminary evidence that they might help prevent colds, too. One study found that children in daycare centers who drank milk fortified with Lactobacillus had fewer and less severe colds. Several studies that examined probiotics combined with vitamins and minerals also found a reduction in the number of colds caught by adults, although it’s not possible to say whether the vitamins, minerals, or probiotics were most responsible for the benefit.
• Vitamin C — Despite the popular belief that vitamin C can cure the common cold, the scientific evidence hasn't found that to be true. Only a small reduction in the duration of a cold (about 1 day) has been found when some people take vitamin C supplements regularly (not just at the beginning of a cold). The only other piece of evidence supporting vitamin C for preventing colds comes from studies examining people exercising in extreme environments (athletes such as skiers and marathon runners, and soldiers in the Arctic). In these studies, vitamin C did seem to reduce the risk of getting a cold. Talk to your doctor about any pros and cons with regards to using vitamin C during cold and flu season. Some people believe that you have to take very high doses of vitamin C to get any benefit, and they suggest taking enough to cause diarrhea and then reducing the dose. You should only use such high doses of vitamin C under your doctor’s supervision.
• Zinc — Your body needs zinc for its immune system to function properly, so it has long been thought that zinc could help protect against catching a cold. But the evidence has been decidedly mixed, with some studies finding a benefit from zinc lozenges but others showing no effect. Recently, a review of studies that compared zinc to placebo found that most of them had flaws that made any positive results unreliable. Only four studies were deemed reliable, and three found no benefit from zinc lozenges. The remaining positive study suggested that zinc nasal sprays might help reduce nasal stuffiness. If you do decide to try zinc lozenges for a cold, remember that getting too much zinc (more than 50 mg per day over a long period of time) can be dangerous.

Herbs

The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, can trigger side effects and can interact with other herbs, supplements, or medications. For these reasons, herbs should be taken with care, under the supervision of a healthcare practitioner. Before giving any herbs to a child to treat a cold, talk to your pediatrician.

Echinacea (Echinacea purpurea, 300 mg three times per day) – Although evidence on whether echinacea works to prevent or treat colds has gone back and forth, recent evidence is encouraging. An analysis of 14 scientific studies found that people who took echinacea reduced their risk of getting a cold by 58 percent and reduced the duration of a cold by an average of a day and a half. However, many of the studies used echinacea in combination with another herb or vitamin, so it’s impossible to say which one was responsible for the benefit. Echinacea should not be used by women who are pregnant or breastfeeding, or by anyone taking drugs that suppress the immune system (such as corticosteroids or methotrexate).

Preventing colds

In addition to echinacea, several other herbs that are used to strengthen the immune system may also be beneficial in preventing you from catching a cold. As is true with echinacea, these herbs should be avoided by anyone taking drugs to suppress their immune system.

• Andrographis (Andrographic paniculata) — One study found that andrographis, an herb used in Ayurvedic medicine, combined with eleuthero or Siberian ginseng (Eleutherococcus senticosus) in a formula called Kan Jang, helped reduce cold symptoms.
• Garlic (Allium sativum) — In one study, people who took garlic for 12 weeks between November and February had 63 percent fewer colds than people who took placebo. Those who did get a cold recovered about one day faster. Because garlic can increase the risk of bleeding, people who take anticoagulants (blood-thinners, such as aspirin or warfarin) should not take garlic. Women who are pregnant or breastfeeding should talk to their doctor before taking garlic supplements.
• Ginseng (Panax quinquefolius, 400 mg per day) — At least two studies suggest that taking American ginseng may help prevent colds, as well as reduce the number of colds experienced and the severity of symptoms.

Treating colds

• Elder or elderberry (Sambucus nigra) — By lessening congestion and possibly helping you sweat, elder may help reduce the symptoms of colds and flu. One study suggested that using a standardized elderberry extract, Sambucol™, could shorten the duration of flu by about three days. Sambucol™ also contains other herbs plus vitamin C, so it isn’t known whether elder by itself would have the same effect. Pregnant and breast-feeding women should not take elder.
• Eucalyptus (Eucalyptus globulus) — Eucalyptus is used in many remedies to treat cold symptoms, particularly cough. It can be found in many lozenges, cough syrups, and vapor baths throughout the United States and Europe. Fresh leaves can be used in teas and gargles to soothe sore throats. Ointments containing eucalyptus leaves are also applied to the nose and chest to relieve congestion and loosen phlegm.
• Goldenseal (Hydrastis canadensis) — Goldenseal is often combined with echinacea in herbal cold remedies, although scientific evidence that it works is lacking. Women who are pregnant or breast-feeding should talk to their doctor before taking goldenseal.
• Licorice (Glycyrrhiza glabra) — Licorice root is a traditional treatment for sore throat, although scientific evidence is lacking. Licorice interacts with a number of medications, so ask your doctor before taking it. People with high blood pressure or heart disease, women who are pregnant or breast-feeding, and those who take anticoagulants (blood thinners) should not take licorice.
• Marshmallow (Althea officinalis) — Although there isn’t any scientific evidence that it works, marshmallow has been used traditionally to treat sore throat and cough.
• Peppermint (Mentha x piperita) — Like eucalyptus, peppermint is widely used to treat cold symptoms. Its main active agent, menthol, is a good decongestants. Menthol also thins mucus and works as an expectorant, meaning that it helps loosen and break up phlegm. It is soothing and calming for sore throats and dry coughs as well.
• Slippery elm (Ulmus fulva) — Slippery elm may help ease sore a sore throat and has been used traditionally for this purpose, although scientific evidence is lacking.

Homeopathy

Although very few studies have examined the effectiveness of specific homeopathic therapies, professional homeopaths may consider the following remedies for the treatment of the common cold based on their knowledge and experience. It is important to note, however, that cold symptoms are viewed in homeopathic medicine as the body's natural way of eliminating a virus. For this reason, homeopathic doctors may recommend no treatment at all. If a remedy is selected, usually it is intended to boost the body's natural immune response. Before prescribing a remedy, homeopaths take into account a person's constitutional type. A constitutional type is defined as a person's physical, emotional, and psychological makeup. An experienced homeopath assesses all of these factors when determining the most appropriate treatment for each individual.

• Aconitum — for symptoms including fever, anxiety, and thirst, that start abruptly, often following exposure to a cold climate or draft; most effective during the first 24 hours of the illness
• Allium cepa — for colds with clear watery discharge that burns and/or irritates the nostrils; red, burning eyes; and symptoms that worsen in warm rooms and in the evening
• Arsenicum album — for colds with watery, burning discharge from the eyes and nose, throbbing headache, nasal congestion that is not relieved by sneezing, dry mouth, sensitivity to cold, and a thirst for small sips of fluid
• Belladonna — for colds with sudden onset of high fever, flushed face, watery nasal discharge, sore throat, throbbing headache, earache, and cough that tends to worsen at night; this remedy is most appropriate for individuals who are often agitated and sometimes delirious; these symptoms may cause children to cry
• Bryonia — for chest colds with spastic cough that produces only a small amount of mucus and sharp chest pain that worsens with inhalation and while coughing; a dull headache, little to no nasal discharge, and sneezing may also be present
• Euphrasia — for colds with excessive, non-irritating watery discharge that tends to worsen in the morning and when the person is lying down
• Ferrum phosphoricum — for the early stages of a cold with slight fever, flushed face (redness may be patchy), and fatigue; may also be used in children with nosebleeds or bloody nasal discharge
• Gelsemium — for colds that have gradual onset with watery nasal discharge that causes irritation, a feeling of fullness or tickling in the nose and/or the back of the throat, muscle aches, fatigue, lack of energy, lightheadedness or spaciness, and a headache with pain in the back of the head
• Hepar sulphuricum — for late stages of a cold when nasal discharge turns from watery to thick, yellow, and foul smelling; symptoms tend to worsen in the evening and with cold and wind
• Mercurius — for fluctuating body temperature and thick, yellow nasal discharge with a foul odor; symptoms may also include bad breath and a swollen tongue
• Pulsatilla — for coughs and nasal congestion with thick, yellow-green mucus that does not burn the skin; symptoms tend to worsen in warm, stuffy rooms and when the person is lying on his or her back; this remedy is most appropriate for children (even newborns) and adults who are weepy, have mood swings, and are easily influenced by others

Mind-Body Medicine

A study of a small number of university students suggests that practicing relaxation techniques on a regular basis may help reduce the duration of a cold or the flu. A similar study of children reached the same conclusion. Some good stress reduction techniques include meditation, deep relaxation, yoga, tai chi, and breathing exercises.

Pregnancy

Tell your healthcare provider if you are pregnant or think you are pregnant. Some medications, herbs, and supplements may be harmful to your baby and should not be taken if you are pregnant or trying to become pregnant.

Special Populations

If you have asthma, emphysema, or any other respiratory disease, you should talk to your doctor as soon as you develop cold symptoms.

Warnings and Precautions

If your symptoms aren’t better in 7 to 10 days, you should call your doctor. Other reasons to see your doctor include high fever (above 102° Fahrenheit), thick, green nasal discharge, or development of a productive cough (cough with phlegm), especially if it is thick and green as well.

Prognosis and Complications

Colds usually get better within 7 to 10 days. Some potential complications include:

• Worsening of a pre-existing respiratory condition, such as asthma or emphysema
• Bronchitis
• Pneumonia
• Ear infection
• Sinusitis

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