About Cold Sores

Cold Sore Image

Oral herpes is a viral infection characterized by outbreaks of mouth lesions commonly known as cold sores or fever blisters. The initial infection typically occurs in childhood. Although a large majority of the population has been infected by herpes, most do not show signs or symptoms.

People who do get sick with the initial infection develop painful sores inside the mouth, affecting the back of the throat, roof of the mouth, tongue, and sometimes the cheeks and inside of the lips. They may feel quite sick, with fever, enlarged lymph nodes, sore throat and bad breath. Though the symptoms completely subside within 10 to 21 days, the virus remains in the body and lies dormant (inactive) until reactivated by certain factors such as stress, menses, or sun exposure.

Subsequent flare-ups or reactivation of the virus, known as recurrent herpes simplex, affects the outside, as opposed to the inside, of the mouth, usually at the edge of one area of the lip. These recurrences are much milder and generally last for eight to 10 days.

What Causes Oral Herpes?

  • Herpes simplex virus type 1 (HSV-1) is the most common cause of cold sores.
  • Herpes simplex virus type 2 (HSV-2), the virus that commonly causes genital herpes, may also cause cold sores.
  • The reason some people get recurrent cold sores while others do not is unclear. However, in people who do develop recurrences, factors that seem to induce them include anxiety, stress, gastrointestinal disturbance, fatigue, cold, infection, wind, sunlight, menstruation, and fever.
  • People with weakened immune systems, such as those undergoing cancer treatment or who have HIV or AIDS, are at greater risk for more severe and more frequent recurrences.

Symptoms of Oral Herpes

Recurrent HSV infection:

  • A tingling sensation or discomfort one to two days prior to the appearance of the cold sore
  • Small, raw, open sores appearing on the outside edges of the lips
  • Scabbing of the sores within 48 hours. The sores usually heal completely within eight to 10 days.
  • Fever blisters
  • Red blisters on the lips, nostrils, cheeks or fingers
  • Eyes become red, painful, teary and sensitive to light if infected.
  • High fever
  • Swollen glands in the neck
  • Red, swollen, and sensitive gums
  • Difficulty swallowing
  • Headaches
  • Loss of appetite
  • Bad breath
  • Sores on the hands, face and sometimes genitals
  • Difficulty sleeping at night

Cold Sore Prevention

  • Avoid intimate contact with someone who has active sores, to prevent the transmission of the virus.
  • Try to determine which factors precipitate a flare-up and plan to avoid them or to lessen their severity. For example, if sunlight is a factor, apply sunblock to your lips before going outdoors or wear a wide-brimmed hat.
  • Avoid sharing eating utensils, cups, bedding, towels, or other items with an infected person.
  • Avoid touching the eyes after touching scabs and blisters.
  • Good health and hygiene can help decrease outbreaks of cold sores and herpes.
  • Wash your hands thoroughly after touching a cold sore.
  • Avoid touching your genitals after touching your cold sore, this might develop into genital herpes.
  • Change your toothbrush.
  • Take supplement, or eat foods high in lysine.
  • Lessen stress in your life as much as possible.
  • Keep your immune system healthy and working well and eat a well balanced diet.

Oral Herpes Diagnosis

  • Patient history and physical examination are needed.
  • Microscopic examination of scrapings from a lesion, or of a culture of fluid from blisters or sores, is sometimes required when the diagnosis cannot be made by history and physical examination alone.

Oral Herpes Treatment

  • Because open sores increase the risk of bacterial infection, a topical antibacterial ointment applied several times daily is prudent. If bacterial infection does develop, your doctor may prescribe an antibiotic.
  • The antiviral drugs acyclovir, famciclovir, or valacyclovir may be prescribed for persons with primary infection inside the mouth and also for persons with severe or prolonged recurrences. Antiviral medications help tremendously in relieving symptoms
  • Application of topical penciclovir cream, an antiviral drug, may speed the healing process in some people.
  • Application of lemon balm minimizes herpes outbreaks.

Sitavig (acyclovir) buccal tablet was approved by the U.S. Food and Drug Administration (FDA) in April 2013 to treat recurrent cold sores in adults with a healthy immune system. One tablet is applied as a single 50 mg dose to the upper gum region—above one of the incisors. The medication should be applied within an hour after the onset of symptoms (e.g., tingling sensation) on the same side as the tingling—before cold sores appear. It should be held in place for about 30 seconds to ensure adhesion. Side effects are usually minor and include pain at the site of application and headache.

When To Call a Doctor about Oral Herpes

  • Call your doctor if you have a primary infection (affecting the inside of the mouth and throat).


Johns Hopkins Symptoms and Remedies: The Complete Home Medical Reference

Simeon Margolis, M.D., Ph.D., Medical Editor

Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50

Updated by Remedy Health Media

Publication Review By: the Editorial Staff at Healthcommunities.com

Published: 16 Nov 2011

Last Modified: 13 Nov 2014