Cold Sores

A common viral infection that affects the skin. In most cases, people become infected with the virus in childhood. The first time a person (usually a child) is infected, symptoms may includes:

  • mouth sores
  • sore throat
  • fever
  • aching
  • tiredness
  • problems with eating
  • swollen glands.

The virus then stays inactive in the body (sometimes for months or years), until an active infection occurs and cold sores result

Frequent Signs and Symptoms

Cold sores usually involve the lips. In some cases, they occur on nostrils, cheeks, or fingers. Prior to a cold sore, the skin area may feel itchy, tingly, or sensitive.

A cluster of small, painful, fluid-filled blisters appear in the affected area. The blisters break and ooze. A yellow crust forms and sloughs off, leaving pink skin and no scarring.


Herpes simplex virus type 1, or, less often, herpes simplex type 2 (the cause of genital herpes). The virus is spread from person to person by contact with fluid from a cold sore, saliva, contact with an item that has the germs on it, or sharing food or drinks with an infected person. The blisters and open sores can spread the virus until they heal.

Risk factors (listed below) may trigger an outbreak of cold sores. Cold sores also recur for unknown reasons.

Risk Increases With

  • physical or emotional stress
  • illness, including a cold, flu, or fever from any cause
  • menstrual periods
  • dental treatment that stretches the mouth
  • weak immune system due to illness or drugs
  • exposure to the sun
  • certain foods or drugs
  • eczema (a skin infection)
  • in daycare settings, sharing toys that children put in their mouths

Preventative Measures

  • avoid contact (such as kissing or sharing food) with someone who has an active cold sore
  • wash your hands often when you have a cold sore; this can help prevent spreading the virus
  • use a sunscreen

Expected Outcomes

Recovery takes a few days to a week. Recurrence will vary for different people. Cold sores may recur often or rarely. Complications are unlikely.

Possible Complications

Rarely, infection spreads to other places in the body, such as the eyes and brain. Prompt treatment is vital.

Diagnosis & Treatment

General Measures

  • Most people will use self-care to treat cold sores:
    • Apply ice to the affected area, or use nonprescription products for cold sores, to ease discomfort.
    • Don’t squeeze or pick at the blisters. Avoid touching them except to apply cream or ointment. Then wash hands carefully. Be careful about touching other places in the body, especially the eyes and genital area, where the infection could spread.
    • Don’t share lip products, or cups and other utensils.
  • See your health care provider if you are concerned about the symptoms. An exam of the infected area can confirm the diagnosis. Rarely, a medical test may be done of fluid from the sore.
  • Medical treatment may include prescription drugs.


  • Use aspirin, acetaminophen, or ibuprofen to relieve minor pain. Don’t give aspirin to children under 18.
  • Nonprescription creams or ointments for cold sores may be used.
  • Antiviral drugs may be prescribed. They can be taken by mouth or applied to the skin.


No limits on physical activity. Avoid close contact with others, especially newborns and persons who have weak immune systems.


No special diet.

Notify Our Office If

The following occur with a cold sore:

  • the cold sore does not heal in a week
  • signs of infection, such as fever or pus, instead of clear fluid in the blister; sores develop on the genitals, or the eyes become infected
  • you have a weak immune system due to illness or drugs