Encyclopedia / C / Common Cold

Common Cold

What Is A Common Cold?

“Common cold” is a general term for a group of minor, highly contagious viral infections that cause inflammation of the mucous linings of the nose and throat. Cold symptoms generally develop one to three days after exposure to the virus, and the virus is contagious for the first two to three days of symptoms. Colds tend to be more frequent in the winter than in the summer, and they’re more common among children than adults, since immunity to many cold viruses develops with age.

No cure for the common cold exists, but spontaneous recovery generally occurs within a week to 10 days. Colds can cause serious complications in people who suffer from chronic respiratory disorders and other medical conditions.

Who Gets A Common Cold?

Anyone can catch a cold. Adults average about two colds a year, and children typically get them more often.


  • Symptoms of the common cold usually appear 24 to 72 hours after exposure to the virus.
  • Often, the first symptom to develop is irritation in the nose and throat, followed by nasal congestion, sore throat (pharyngitis), sneezing, coughing, and runny nose (rhinorrhea).
  • Nasal secretions are thin and profuse initially, but become thick and yellow as infection progresses.
  • Headache, body pain, and malaise (generally feeling unwell) also may occur.
  • Fever is rare.
  • Cold symptoms can be intensified by the following factors: allergies, excessive fatigue, emotional stress, and a weakened immune system.
  • Symptoms usually last 5 to 10 days. Persistent, mild coughing is common following the resolution of acute symptoms and may last 2 weeks.
  • Complications of a cold include acute viral sinusitis (inflammation of the sinuses), coexistent bacterial infection, and lower respiratory infection (bronchitis).

Causes/Risk Factors

  • Over 200 different strains of viruses (predominantly rhinoviruses and coronaviruses) cause colds. Rhinoviruses tend to infect people in late summer and early autumn. Other types of viruses are more likely to cause winter and early spring colds.
  • Infected persons may spread cold viruses by direct contact—such as shaking hands or kissing—or through the air—by coughing or sneezing. The virus may also spread via contaminated objects, such as drinking glasses or playing cards.
  • Three factors that influence transmission include the amount of time spent around the cold sufferer, the volume of the secretions, and the amount of virus in the secretions. Often, members of the same household tend to share their colds.
  • Contrary to popular belief, colds are not caused by fatigue, cold air, wet hair, or wet clothes.

What If You Do Nothing?

The common cold seldom causes serious complications. Although acute cold symptoms can be debilitating‚ colds are temporary and self-limiting. Most colds last a week or less, but symptoms can last 2 weeks.

Common Cold Diagnosis

  • Diagnosis of the common cold is typically made by observing symptoms and their course.
  • Examination of the throat and nasal passages often reveals characteristic irritation—swelling and redness. Lung examination performed with a stethoscope usually reveals normal function.
  • A throat culture can differentiate the common cold from a bacterial infection, such as strep throat. Cultures usually are performed if the throat or tonsils are red, swollen, and/or have white spots of purulent exudate (pus); if fever is present; if the lymph nodes in the neck are swollen and tender; or if cold symptoms persist longer than expected.

Treatment for the Common Cold

  • Over-the-counter (OTC) nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen may be used to relieve headaches and muscle aches and reduce fever. Acetaminophen is recommended for children under 12.
  • Use cold medications sparingly. Avoid “shotgun” remedies that claim to treat all cold symptoms—they are often ineffective. Instead, choose a product made to relieve your most bothersome symptoms.
  • Nasal decongestant sprays and drops should not be used for more than a few days, as they may actually aggravate congestion with extended use. If you are coughing up mucus, avoid cough suppressants, since they will permit mucus to accumulate in the lungs.
  • Drink plenty of fluids to help loosen mucus secretions in the lungs. Hot drinks are comforting and their vapor may help increase the flow of nasal secretions. Although warm alcoholic beverages may sound tempting, it’s best to avoid alcohol as it dilates blood vessels and may produce more congestion.
  • Gargle with warm, salt water several times a day to soothe a sore throat. Hard candy or lozenges can help keep the throat lubricated.
  • Rest at home for the first day or two to aid recovery and to prevent spreading the cold to others. Exercise if you feel up to it, but avoid strenuous physical activity if you feel too tired or unfit, or if you have a fever.
  • A humidifier can increase moisture in the air you breathe and sometimes make you feel better—at least temporarily. But humidifiers can harbor molds, which may cause allergic reactions. Clean the tank daily, rinsing with a mild solution of chlorine bleach, and refill it with fresh water.
  • Antibiotics do not help treat a cold, but they may be prescribed if you develop a secondary bacterial infection.
  • Several dietary supplements are promoted as cold remedies, including vitamin C, echinacea, and zinc. Research on their effectiveness is mixed—but at most, it appears these supplements may ease symptoms or shorten the duration of a cold.


  • Wash hands frequently with soap and warm water, especially after visiting public places.
  • Avoid touching the face with unwashed hands.
  • Don’t share towels or drinking glasses.
  • Try to limit exposure to people with colds.
  • There is no evidence that vitamin C or any other supplement can prevent a cold.

When to Call Your Doctor

  • Call a doctor if cold symptoms persist for more than two weeks, especially if they increase in severity.
  • Call a doctor if you suffer from a chronic respiratory disorder and you catch a cold.

Reviewed by Michael S. Soliman, M.D., family medicine physician in private practice and hospitalist at Mount Holyoke Medical Center, Mount Holyoke, MA.