Cold Sores: Causes and Treatments

Close-up of man with two cold sores on his lip.
Cold sore outbreaks can be triggered by stress. See more pictures of skin problems.

It can happen at the worst possible times. You're stressed out about a speech you have to give at work, or maybe you're nervous about a first date, and you start to feel a prickling and burning in your lip. Soon, a hard bump that feels like a pimple forms under the skin's surface. But you know this isn't a zit; you're getting a cold sore.

You're not alone. Fifteen to 30 percent of the population suffers from cold sores, or fever blisters [source: McKinley]. Soon after those first symptoms show up, red blisters appear on or around the lips. After a few days, the painful blisters break, release a clear fluid and a scab forms. Cold sore sufferers may have to deal with fever, sore throat and mouth, or swollen lymph nodes in the neck [source: Web MD].


Cold sores can be unsightly and embarrassing. As you'll learn on the next page, they're caused by the same virus that causes genital herpes. The virus can be passed through sexual contact, which sometimes embarrasses those suffering from cold sores because the disease has a sexual or promiscuous stigma attached to it. But as you'll see, the virus is just as easily spread through saliva, so this association isn't particularly accurate [source: Mayo Clinic]. There is currently no cure for the virus that causes cold sores, and people who suffer from them generally experience a few outbreaks a year [source: McKinley]. But there are ways to reduce the number of outbreaks.

Read on to learn how cold sores are spread from person to person, what some of the known causes of cold sore outbreaks are and how you can get rid of cold sores once they do appear.


Cold Sore Causes

Cold sores are caused by the herpes simplex virus (HSV), an infection that attacks the skin and nervous system [source: McKinley]. There are two main strains of HSV, appropriately called HSV-1 and HSV-2. HSV-1 generally causes cold sores and HSV-2 is usually the cause of genital herpes, but each virus can cause both mouth and genital sores [source: Mayo Clinic].

Cold sores occur when HSV is passed from an infected person to an uninfected person. HSV is contained in the liquid that leaks out of a sore or blister when it breaks open. It is spread when an uninfected person comes in contact with this fluid, either by touching it directly or through the saliva of the infected person. HSV can be passed by sharing eating utensils, razors or towels, by kissing an infected person, or by directly touching the infected area. HSV can also be sexually transmitted [source: Mayo Clinic].


Once a person is infected with HSV, cold sores are likely to reappear a few times per year. However, cold sores are often triggered by specific events or conditions. By avoiding these circumstances, a person can minimize his or her cold sore outbreaks. Triggers include overexposure to sunlight, stress, fatigue, food allergies and hormonal changes -- particularly those of women during the menstrual cycle. Injury to the lips or gums -- or dental treatment that puts stress on areas around the mouth -- can also set off an outbreak. People with weak or impaired immune systems tend to have more cold sore outbreaks, and those cases are typically more severe [source: Web MD].

In the next section, discover different ways to get rid of cold sores.


How to Get Rid of Cold Sores

There is no cure for cold sores or herpes simplex -- the virus stays inside the infected person for the rest of his or her life. Even though there's no definite way to prevent or cure cold sore outbreaks, most will heal and go away on their own in a few days to two weeks [source: WebMD].

However, there are therapies available that can treat cold sore symptoms while helping the body heal more quickly. For the first outbreak of cold sores, there are certain over-the-counter cold sore medications that can reduce irritation and improve healing time. For those who have frequent outbreaks, oral medications can be prescribed to lessen cold sore frequency. When a person has a weakened immune system, an antibiotic may be prescribed as well to avoid additional complications from HSV [source: WebMD].


For more information about treating cold sores, read Treating Cold Sores: Fast Facts.

Even though there's no definite way to prevent cold sore outbreaks, there are certain methods that can be used to resist the triggers. For example, an infected person should always wear sunscreen or lip balm when going out in direct sunlight. Those who practice stress management techniques tend to have fewer outbreaks, as do those who exercise regularly and get enough sleep [source: McKinley].

Further steps can be taken to help eliminate the painful symptoms of cold sore outbreaks. Placing a cold wet towel on the sores for 20 minutes at a time, three times a day, can reduce redness and swelling. Mouth rinses with baking soda can reduce the pain inside the mouth, and avoiding acidic foods will prevent further irritation. And certain over-the-counter products -- such as Anbesol -- can numb sore areas on the lips [source: WebMD].

To read more about cold sores, look over the links on the next page


Lots More Information

Related HowStuffWorks Articles

  • Centers for Disease Control and Prevention. "Media Statement." February 26, 2009. (Aug.5, 2009).
  • Mayo Clinic Staff. "Cold sore: Causes." March 13, 2008. (Aug.5, 2009).
  • Mayo Clinic Staff. "Cold sore: Definition." March 13, 2008. (Aug.5, 2009).
  • Mayo Clinic Staff. "Genital herpes: Definition." May 22, 2009. (Aug.5, 2009).
  • McKinley Health Center. "Herpes Simplex (cold sores)." June 21, 2007.(Aug.5, 2009).
  • WebMD. "Canker Sores: Overview." February 8, 2009. (Aug.5, 2009).
  • WebMD. "Cold Sores - Home Treatment." March 13, 2008. (Aug.5, 2009).
  • WebMD. "Cold Sores - Symptoms." March 13, 2008. (Aug.5, 2009).
  • WebMD. "Cold Sores - Topic Overview." March 13, 2008. (Aug.5, 2009).
  • WebMD. "Cold Sores - Treatment Overview." March 13, 2008. (Aug.5, 2009).