• Cold Sores

    (Fever Blisters; Herpes Labialis; Herpes Stomatitis; Herpes Simplex)


    Cold sores are small, painful, fluid-filled blisters. They are usually found at the border of the lip.
    Herpes Simplex on the Lips
    Copyright © Nucleus Medical Media, Inc.


    Cold sores are usually caused by the herpes simplex 1 virus. Rarely, cold sores are caused by the herpes 2 virus. The herpes 2 virus causes genital herpes. The two viruses are related, but different.
    In most cases, people contract the virus as young children. The first episode of illness with herpes simplex 1 virus can cause a body-wide illness. After that, the virus lies quietly in the skin until it is reactivated. This is when the virus causes cold sores.
    You may get the virus from:
    • Contact with the fluid from a cold sore of another person, or genital herpes sores
    • Contact with the eating utensils, razors, towels, or other personal items of a person with active cold sores
    • Sharing food or drink with a person with active cold sores
    • Contact with the saliva of a person who has the herpes simplex virus

    Risk Factors

    Infection with the herpes virus is very common. Everyone is considered at risk for a herpes infection.
    If you have a herpes infection, factors that can trigger cold sores include:
    • Infection, fever, cold, or other illness
    • Exposure to sun
    • Physical or emotional stress
    • Certain drugs
    • Weakened immune system
    • Menstruation
    • Physical injury or trauma
    • Dental or other oral surgery
    Cold sores often form without a known trigger.


    The initial herpes simplex 1 infection can cause flu-like symptoms. The recurring infections will result in cold sores.
    A cold sore occurs most often on the lips, but can occur in the mouth or other areas of the skin. You may have some symptoms the day just before a cold sore appears. You may notice some itching, tingling, burning, or pain in the area the cold sore appears. Cold sore blisters:
    • Are small, painful, fluid-filled, red-rimmed blisters
    • Will dry up with a crust and a shallow sore after a few days


    The doctor will ask about your symptoms and medical history and examine the blisters. Usually, the doctor can easily diagnose a cold sore by looking at it. In rare cases, the doctor may need to take a piece of the blister to be analyzed. A blood sample may also be taken for testing.


    Cold sores will usually heal within two weeks even without treatment. However, certain treatments may help decrease symptoms. They may also shorten the time that you have a sore. Treatment options include:
      To reduce pain consider:
      • Nonprescription cold sore/fever blister cremes and ointments
      • Putting ice on blisters to lessen pain
      • Mouthwash with lidocaine—To treat cold sores in the mouth
    • Medications that may shorten the outbreak include:
    • Antiviral creams or ointments—May also help decrease pain
    • Oral antiviral medications—May be given the moment you feel a cold sore coming or can be taken on a regular basis to suppress frequent outbreaks. Examples include:
      • Acyclovir (Zovirax)
      • Valacyclovir (Valtrex)
      • Famciclovir ( Famvir)
    • Avoid rubbing or scratching blisters, which can delay healing. It can also increase your chance of a second infection.


    To prevent the oral spread of the herpes simplex 1 or 2 virus:
    • Be careful around people who have active cold sores. Avoid skin contact and kissing. Do not share food, drink, or personal items.
    • Avoid performing oral sex on a person with active genital herpes.
    • If you have an active cold sore, avoid touching the infected area. This will help keep you from spreading the virus to other people and/or other parts of your body. If you do touch the area, wash your hands.
    The herpes virus will never leave your body once you have it. There is no cure for the infection. If you already have a herpes infection, to prevent future outbreaks of cold sores or blisters:
    • Avoid long periods of time in the sun.
    • Use sun block on lips and face when in the sun.
    • Get adequate rest and relaxation. Try to minimize stress.
    • If you have outbreaks often, talk to your doctor about taking antiviral medicines.


    American Academy of Dermatology http://www.aad.org

    FamilyDoctor.org http://familydoctor.org


    Canadian Family Physician http://www.cfpc.ca/

    SkinCareGuide.ca http://www.skincareguide.ca/


    Herpes labialis. EBSCO DynaMed website. Available at: https://dynamed.ebscohost.com/about/about-us. Updated March 27, 2011. Accessed August 12, 2012.

    Arduino PG, Porter SR. Oral and perioral herpes simplex virus type 1(HSV-1) infection: review of its management. Oral Diseases. 2006;12:254-270.

    Cold sore. Mayo Clinic website. Available at: http://www.mayoclinic.com/health/cold-sore/DS00358/DSECTION=treatments-and-drugs. Updated May 23, 2012. Accessed August 9, 2012.

    Emmert DH. Treatment of common cutaneous herpes simplex virus infections. Am Fam Physician. 2000;61:1697.

    Groves MJ. Transmission of herpes simplex virus via oral sex. Am Fam Physician. 2006;1;73:1153; discussion 1153.

    Herpes simplex. American Academy of Dermatology website. Available at: http://www.aad.org/public/publications/pamphlets/viral%5Fherpes%5Fsimplex.html. Accessed August 9, 2012.

    Herpes. American Academy of Family Physicians. Family Doctor.org website. Available at: http://familydoctor.org/online/famdocen/home/common/sexinfections/sti/091.html. Updated October 2009. Accessed November 15, 2010.

    Herpes simplex. DermNet NZ website. Available at: http://dermnetnz.org/viral/herpes-simplex.html. Updated June 2008. Accessed August 12, 2012.

    Schmid-Wendtner MH, Korting HC. Penciclovir cream—improved topical treatment for herpes simplex infections. Skin Pharmacol Physiol. 2004;17:214-8.

    Spruance S, Bodsworth N, Resnick H, et al. Single-dose, patient-initiated famciclovir: a randomized, double-blind, placebo-controlled trial for episodic treatment of herpetic labialis. J Am Acad Dermatol. 2006;55:47-53.

    Spruance SL, Jones TM, Blatter MM, Vargas-Cortes M, et al. High-dose, short-duration, early valacyclovir therapy for episodic treatment of cold sores: results of two randomized, placebo-controlled, multicenter studies. Antimicrobial Agent Chem. 2003;1072-1080.

    Revision Information

  • Can we help answer your questions?

    Wellmont Nurse Connection is your resource for valuable health information any time, 24 hours a day, seven days a week. Speak to a Nurse any time, day or night, at (423) 723-6877 or toll-free at 1-877-230-NURSE.