Common Cold


The common cold is a set of symptoms that result from a viral infection. Symptoms commonly include sneezing, runny nose, congestion, and cough. Symptoms of the common cold may be treated with an antihistamine, decongestant, or acetaminophen. Some newer antiviral drugs may reduce the duration and/or severity of symptoms from the common cold. However, the best treatment is often rest and time so that your immune system can eradicate the infection. Prolonged cold symptoms may indicate that you don’t have enough white blood cells to fight the infection.

What causes the common cold?

There are many different viruses that can cause the common cold, but often it is caused by a class called rhinoviruses. The virus is passed from other people; it is not cold weather that causes a cold, but the fact that cold weather causes people to gather together indoors, making transmission of the virus easier during the winter. The virus generally moves from someone else's hands to your hands (either directly or through some intermediate surface such as a door knob), and from your hands into your nose or eyes. It can also be passed via airborne particles, (e.g., inhaling the virus when someone who has it coughs or sneezes near you). The rhinovirus gets into the cells lining your nose and starts reproducing.

To fight the infection, your body’s immune system reacts to the presence of the virus by opening up blood vessels, resulting in inflammation and the feeling of congestion, and by increasing mucus secretions, causing a runny nose. The irritation caused by the virus and all of the fluid causes sneezing. If the virus makes it into the cells lining the lungs, then mucus is also produced in the lungs, which results in a cough. A cough can also be produced by leaking mucous from the upper respiratory track into the trachea.

There are possible causes of cold symptoms other than the common cold. For example:

  • A runny nose, irritated nose, or blocked sinuses may be caused by allergies.
  • A sore throat may be caused by allergies with postnasal drip.
  • A sore throat may be caused by bacteria, including streptococcal bacteria, a potentially serious infection.
  • Nasal congestion and irritation may occur due to irritants, such as smoke and pollution.
  • Worsening congestion and runny nose may be caused by overuse of nasal sprays, such as Afrin, to clear your nasal passages. Nasal spray should not be used longer than 3 to 5 days in a row.
  • Congested sinuses may be caused by a deviated septum, where the membrane that separates the nostrils is off-center, which is usually congenital or due to a broken nose or trauma to the face.

What are symptoms of the common cold?

Symptoms of the common cold may include one or more of the following:

  • Sore throat                                                                                            
  • Cough
  • Swollen or irritated nose
  • Sneezing
  • Runny nose
  • Chills
  • Congested nose and/or sinuses
  • Headache
  • Postnasal drip (mucus running down the back of your throat)   

Why is the common cold important for cancer patients?

The body’s primary defense against the common cold is the white blood cells that make up the immune system. Not everyone gets every cold.  If you have a strong immune system, you are less likely to contract a cold virus, even if you are exposed to it.

Many cancer patients have weakened immune systems. Specifically, cancer patients may have abnormally low levels of neutrophils in the circulating blood, a condition called neutropenia. Neutrophils are a kind of white blood cell that helps prevent and fight infections. The most common reason that cancer patients experience neutropenia is as a side effect of chemotherapy. Chemotherapy-induced neutropenia increases a patient’s risk of infection and disrupts cancer treatment.

Fortunately, neutropenia can be prevented. Prevention of neutropenia allows patients to receive their scheduled treatment and reduces the risk of infection and hospitalization. Currently, the two drugs approved by the U.S. Food and Drug Administration for the prevention of chemotherapy-induced neutropenia are Neupogen® (filgrastim) and Neulasta® (pegfilgrastim), a longer-lasting drug requiring less frequent injections. Leukine® (sargramostim) is another drug used for this purpose.


For more information, go to the section on low white blood cell counts (neutropenia).

How is the common cold treated?

Antibiotics are not a treatment for viral infections, but you may be prescribed an antibiotic if you have the streptococcus bacteria (strep) or other bacterial infection or if your doctor wants to protect you against developing a bacterial infection. The main reason to treat a possible strep infection is to prevent rheumatic fever. Rheumatic fever can develop from a strep infection and may involve the heart, joints, skin, and brain. Rheumatic fever is responsible for many cases of damaged heart valves.

The most common antibiotics prescribed for a strep infection are penicillin V or amoxicillin. These antibiotics are prescribed for at least 10 days. Although these are the most common antibiotics prescribed, you may receive another depending on your overall health status.

If you have had a prolonged illness and postnasal drip, you may develop a sinus infection (sinusitis). The antibiotic amoxicillin is usually prescribed for a sinus infection. Dosage is 500 milligrams by mouth, 3 times a day, for 10 to 14 days. There are, however, several other antibiotics that your doctor may prescribe.

Antihistamines may relieve sneezing, watery eyes, and itching, particularly due to allergies, and can prevent nasal congestion. The most common nonprescription antihistamines include Benadryl and Chlor-Trimeton. Side effects of these drugs may leave you drowsy and with a dry mouth.  Newer prescription antihistamines are available that do not cause these side effects. These include Claritin and Allegra. You can take one of these pills daily, every other day, or whenever you have symptoms. These medications may be prescribed alone, or in combination with a decongestant, such as Claritin-D.

Corticosteroids (steroids) are often administered as a nasal spray and work locally to decrease nasal irritation and inflammation. With local administration, only a small amount of the steroid is distributed through your body, reducing the risk of unfavorable long-term side effects of steroids. Common topical nasal steroids include Rhinocort® (budesonide) and Flonase® (fluticasone propionate).

Decongestants are used to treat congestion or relieve “blockage” in the nose or sinuses, or to relieve symptoms of a runny nose. The most commonly prescribed pill to treat congestion is pseudoephedrine. A commonly used nasal spray decongestant is Astelin® (azelastine).

Acetaminophen may relieve joint or throat pain. Standard dosage is two extra-strength tablets every 6 hours as needed, up to 4,000 milligrams per day. It is important not to exceed the recommended daily dose of acetaminophen, as it may cause liver damage.

If you have a bleeding disorder, such as thrombocytopenia, or are on active chemotherapy, you should avoid nonsteroidal antiinflammatory (NSAID) drugs, such as ibuprofen, as well as aspirin because these drugs may interfere with blood platelets and prolong bleeding.

This content was last reviewed August 15, 2010 by Dr. Reshma L. Mahtani.
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