Oral herpes is an infection of the lips, mouth, or gums due to the herpes simplex virus. It causes small, painful blisters commonly called cold sores or fever blisters. Oral herpes is also called herpes labialis.
Oral herpes is a common infection of the mouth area. It is caused by the herpes simplex virus type 1 (HSV-1). Most people in the United States are infected with this virus by age 20.
After the first infection, the virus goes to sleep (becomes dormant) in the nerve tissues in the face. Sometimes, the virus later "wakes up" (reactivates), causing cold sores.
Herpes virus type 2 (HSV-2) most often causes genital herpes. However, sometimes HSV-2 is spread to the mouth during oral sex, causing oral herpes.
Herpes viruses spread easily. You can catch this virus if you:
Parents may spread the virus to their children during regular daily activities.
Some people get mouth ulcers when they first come into contact with HSV-1 virus. Others have no symptoms. Most of the time, symptoms usually occur in children between 1 and 5 years old.
Symptoms may be mild or severe. They often appear within 1 to 3 weeks after you come into contact with the virus. They may last up to 3 weeks.
Warning symptoms include:
Before blisters appear, you may have:
Blisters or a rash may form on your:
Many blisters are called an "outbreak." You may have:
Symptoms may be triggered by:
If the symptoms return later, they are often less severe.
Your health care provider can diagnose oral herpes by looking at your mouth area. Sometimes, a sample of the sore is taken and sent to a laboratory for closer examination. Tests may include:
Symptoms may go away on their own without treatment in 1 to 2 weeks.
Your health care provider can prescribe medicines to fight the virus. This is called antiviral medicine. It can help reduce pain and make your symptoms go away sooner. Medicines used to treat mouth sores include:
These medicines work best if you take them when you have warning signs of a mouth sore, before any blisters develop. If you get mouth sores frequently, you may need to take these medicines all the time.
Antiviral skin creams may also be used. However, they are expensive and often only shorten the outbreak by a few hours to a day.
The following steps can also help make you feel better:
Oral herpes usually goes away by itself in 1 to 2 weeks. However, it may come back.
Herpes infection may be severe and dangerous if:
Herpes infection of the eye is a leading cause of blindness in the United States. It causes scarring of the cornea.
Other complications of oral herpes may include:
Call for an appointment with your health care provider if you have:
Here are some tips to prevent mouth sores:
Do not have oral sex if you have oral herpes, especially if you have blisters. You can spread the virus to the genitals. Both oral and genital herpes viruses can sometimes be spread even when you do not have mouth sores or blisters.
Cold sore; Fever blister; Oral herpes simplex; Herpes labialis; Herpes simplex
Habif TP. Warts, herpes simplex, and other viral infections. In: Habif TP, ed. Clinical Dermatology. 5th ed. Philadelphia, PA: Elsevier Mosby; 2009:chap 12.
Whitley RJ. Herpes simplex virus infections. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 382.
Updated by: Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.
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