(Fever Blisters; Herpes Labialis; Herpes Stomatitis; Herpes Simplex)
by Rick Alan
Cold sores are small, painful, fluid-filled blisters. They are usually found at the border of the lip.
Cold sores are caused by 2 types of herpes simplex viruses. Cold sores are common. In most cases, people contract the virus as young children.
You may get the virus from:
The first episode of illness with herpes virus can cause a body-wide illness. After that, the virus lies quietly in the skin until it is reactivated. The reactivated virus causes a cold sore to appear.
Risk Factors TOP
Factors that can reactivate the virus and lead to an outbreak of cold sores:
It is not always clear what triggers a cold sore.
A cold sore occurs most often on the lips, but can occur in the mouth or other areas of the skin. They are small, painful sores that are fluid filled and red-rimmed blisters.
You may notice some itching, tingling, or burning the day before a cold sore appears. The sores will dry up with a crust and shallow sore after a few days.
You will be asked about your symptoms and medical history. The blisters will be examined.
A cold sore can usually be diagnosed with a visual exam. In rare cases, a sample of the blister may be taken. The sample will be sent to a lab to be tested.
A blood sample may also be taken for testing.
Cold sores will usually heal within 2 weeks even without treatment. However, certain treatments may help decrease symptoms. They may also shorten the time that you have a cold sore. Treatment options include:
To help reduce pain consider:
Prescription antiviral creams or ointments, may also help decrease pain.
Oral antiviral medications may be prescribed to suppress frequent outbreaks. These are taken the moment you feel a cold sore coming.
Avoid rubbing or scratching blisters. This can delay healing and cause an infection.
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.
To reduce help reduce your chances of a viral infection:
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:
American Academy of Dermatology
Family Doctor—American Academy of Family Physicians
Canadian Dermatology Association
Arduino PG, Porter SR. Oral and perioral herpes simplex virus type 1(HSV-1) infection: review of its management. Oral Diseases. 2006;12(3):254-270.
Emmert DH. Treatment of common cutaneous herpes simplex virus infections. Am Fam Physician. 2000;61(6):1697-1706.
Groves MJ. Transmission of herpes simplex virus via oral sex. Am Fam Physician. 2006;73(7):1153.
Herpes simplex. American Academy of Dermatology website. Available at: https://www.aad.org/public/diseases/contagious-skin-diseases/herpes-simplex. Accessed February 15, 2018.
Herpes. Family Doctor—American Academy of Family Physicians Family Doctor website. Available at: https://familydoctor.org/condition/herpes. Updated October 2017. Accessed February 15, 2018.
Herpes simplex. DermNet NZ website. Available at: hhttps://www.dermnetnz.org/topics/herpes-simplex. Updated October 2015. Accessed February 15, 2018.
Oral herpes. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T115104/Oral-herpes . Updated October 5, 2015. Accessed February 15, 2018.
Schmid-Wendtner MH, Korting HC. Penciclovir cream—improved topical treatment for herpes simplex infections. Skin Pharmacol Physiol. 2004;17(5):214-218.
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(1):47-53.
Spruance SL, Jones TM, Blatter MM, 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;47(3):1072-1080.
Last reviewed March 2018 by EBSCO Medical Review Board David L. Horn, MD, FACP
Last Updated: 5/2/2014
EBSCO Information Services is fully accredited by URAC. URAC is an independent, nonprofit health care accrediting organization dedicated to promoting health care quality through accreditation, certification and commendation.
This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.
To send comments or feedback to our Editorial Team regarding the content please email us at email@example.com. Our Health Library Support team will respond to your email request within 2 business days.