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Alternative Names: Cold sore; Fever blister; Herpes simplex - oral; Oral herpes simplex
Causes of Herpes labialis
Herpes labialis is a common disease caused by infection of the mouth area with herpes simplex virus type 1. Most people in the United States are infected with this virus by age 20.
The initial infection may cause no symptoms or mouth ulcers. The virus then remains dormant (asleep) in the nerve tissue of the face. In some people, the virus reactivates and produces recurrent cold sores that are usually in the same area, but are not serious.
Herpes virus type 2, which usually causes genital herpes and can infect babies during birth to infected mothers, can also cause herpes labialis.
Herpes viruses are contagious. Spread may occur through intimate and personal contact, or through contact with infected razors, towels, dishes, and other shared articles. Occasionally, oral-to-genital contact may spread oral herpes to the genitals (and vice versa).
Herpes labialis Symptoms
The first episode may be mild or severe. It usually occurs in children between 1 and 5 years old.
- First symptoms usually appear within 1 or 2 weeks, and as long as 3 weeks, after contact with the virus. Sore throat and fever that can last up to 5 days may occur before the blisters appear. There may also be swollen glands in the neck.
- First episode may last 2 to 3 weeks. The lesions may be on the gums, in the mouth and throat, or on the face. It may hurt to swallow.
Later episodes are usually milder.
- May be triggered by menstruation, sun exposure, fever, stress, or various other unknown causes.
- Warning symptoms of itching, burning, increased sensitivity, or tingling sensation may occur about 2 days before lesions appear.
An outbreak usually involves:
- Skin lesions or rash around the lips, mouth, and gums
- Small blisters (vesicles) filled with clear yellowish fluid
- Blisters on a raised, red, painful skin area
- Blisters that form, break, and ooze
- Yellow crusts that slough to reveal pink, healing skin
- Several smaller blisters that merge to form a larger blister
Tests and Exams
Diagnosis is made on the basis of the appearance or culture of the lesion. Examination may also show enlargement of lymph nodes in the neck or groin.
Viral culture, viral DNA test, or Tzanck test of the skin lesion may reveal the herpes simplex virus.
Treatment of Herpes labialis
Untreated, the symptoms will generally go away in 1 to 2 weeks. Antiviral medications taken by mouth may help the symptoms go away sooner and decrease pain. Acyclovir, famciclovir, and valacyclovir are the three oral treatments currently available.
Herpes sores often come back again and again. The antiviral medicines work best if you take them when the virus is just starting to come back -- before you see any sores. If the virus returns frequently, your doctor may recommend that you take the medicines all the time.
Topical (rubbed onto the skin) antiviral cream (penciclovir andaacyclovir) may be used, but must be applied every 2 hours while you're awake. They are expensive and often only shorten the outbreak by a few hours to a day.
Wash blisters gently with soap and water to reduce the spread of the virus to other areas of skin. An antiseptic soap may be recommended. Applying ice or warmth to the area may reduce pain.
Tips to prevent future outbreaks include applying a sunblock or lip balm containing zinc oxide to the lips when you're outdoors. A moisturizing balm to prevent the lips from becoming too dry may also help.
Herpes labialis usually goes away by itself in 1 to 2 weeks. It may come back. Infection may be severe and dangerous if it occurs in or near the eye, or if it happens in immunosuppressed people.
- Recurrence of herpes labialis
- Spread of herpes to other skin areas
- Secondary bacterial skin infections
- Generalized infection -- may be life-threatening in immunosuppressed people, including those with atopic dermatitis, cancer, or HIV infections
Herpes infection of the eye is a leading cause of blindness in the United States, causing scarring of the cornea.
When to Contact a Health Professional
Call for an appointment with your health care provider if you have :
- Symptoms of herpes labialis that are severe or that don't go away after 2 weeks
- Cold sores near your eyes
- Herpes symptoms and have a weakened immune system (immunosupression) due to disease or certain medications
Prevention of Herpes labialis
Avoid direct contact with herpes sores. Minimize the risk of indirect spread by thoroughly washing items such as towels in hot (preferably boiling) water before reuse. Do not share items with an infected person, especially when they have herpes lesions. Avoid triggers (especially sun exposure) if you are prone to oral herpes.
Avoid performing oral sex when you have active herpes lesions on or near your mouth and avoid receiving oral sex from someone who has oral or genital herpes lesions. Condoms can help reduce, but do not entirely eliminate, the risk of catching herpes from oral or genital sex with an infected person.
Both oral and genital herpes viruses can sometimes be transmitted even when the person does not have active lesions.
Haile-Mariam T, Polis MA. Viral illnesses. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, Pa: Mosby Elsevier; 2009:chap 128.
Habif TP. Warts, herpes simplex, and other viral infections. In: Habif TP, ed. Clinical Dermatology. 5th ed. Philadelphia, Pa: Mosby Elsevier; 2009: chap 12.
Reviewed By: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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