| Herpes labialis | |
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| Classification and external resources | |
Herpes labialis of the lower lip. Note the blisters in a group marked by an arrow. |
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| ICD-10 | B00.1 |
| ICD-9 | 054.9 |
| MeSH | D006560 |
Herpes labialis or "orolabial herpes"[1]:368 is an infection of the lip by herpes simplex virus (HSV-1). An outbreak typically causes small blisters or sores on or around the mouth commonly known as cold sores or fever blisters. The sores typically heal within 2–3 weeks, but the herpes virus remains dormant in the facial nerves, following orofacial infection, periodically reactivating (in symptomatic people) to create sores in the same area of the mouth or face at the site of the original infection.
HSV-1 affected 57.7% of Americans tested in a 1999-2004 study.[2] By age 50, 80%–90% of adults have the virus.[3] More than 50 million adults in the U.S. develop symptomatic episodes every year.[4] Cold sore has a rate of frequency that varies from rare episodes to 12 or more recurrences per year. People with the condition typically experience one to three attacks annually. The frequency and severity of outbreaks generally decreases over time.[5]
The virus is transmitted from cold sores and also when there are no symptoms, as it can make copies of itself on the skin in the absence of a blister.
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In medical contexts, "labia" is a general term for "lip"; "herpes labialis" does not refer to the labia of the genitals, though the etymology is the same. When the viral infection affects both face and mouth, the broader term "orofacial herpes" is used to describe the condition, whereas the term "herpetic stomatitis" is used to specifically describe infection of the mouth; "stomatitis" is derived from the Greek word stoma that means "mouth".
Herpes infections often show no symptoms;[6] when symptoms do appear they typically resolve within two weeks.[7] The main symptom of oral infection is inflammation of the mucosa of the cheek and gums—known as acute herpetic gingivostomatitis—which occurs within 5–10 days of infection. Other symptoms may also develop, including headache, nausea, dizziness and painful ulcers—sometimes confused with canker sores—fever, and sore throat.[7] Primary HSV infection in adolescents frequently manifests as severe pharyngitis with lesions developing on the cheek and gums. Some individuals develop difficulty in swallowing (dysphagia) and swollen lymph nodes (lymphadenopathy).[7] Primary HSV infections in adults often results in pharyngitis similar to that observed in glandular fever (infectious mononucleosis), but gingivostomatitis is less likely.
Recurrent oral infection is more common with HSV-1 infections than with HSV-2. Symptoms typically progress in a series of eight stages (see viral life cycle):
The recurrent infection is thus often called herpes simplex labialis. Rare reinfections occur inside the mouth (intraoral HSV stomatitis) affecting the gums, alveolar ridge, hard palate, and the back of the tongue, possibly accompanied by herpes labialis.[7]
Herpes labialis infection occurs when the herpes simplex virus comes into contact with oral mucosal tissue or abraded skin of the mouth. Infection by the type 1 strain of herpes simplex virus (HSV-1) is most common; however, cases of oral infection by the type 2 strain are increasing.[7]
Cold sores are the result of the virus's reactivating in the body. Once HSV-1 has entered the body, it never leaves. The virus moves from the mouth to quietly reside (“remain latent”) in the central nervous system. In approximately one-third of people, the virus can “wake up” or reactivate to cause disease. When reactivation occurs, the virus travels down the nerves to the skin where it may cause blisters (cold sores) around the lips, in the mouth or, in about 10% of cases, on the nose, chin, or cheeks. Cold sore outbreaks may be influenced by stress, menstruation, sunlight, sunburn, fever, or local skin trauma. Surgical procedures such as dental or neural surgery, lip tattooing, or dermabrasion are also common triggers. HSV-1 can in rare cases be transmitted to newborn babies by family members or hospital staff who have cold sores; this can cause a severe disease called Neonatal herpes simplex.
People can transfer the virus from their cold sores to other areas of the body, such as the eye, skin, or fingers; this is called “autoinoculation." Eye infection, in the form of conjunctivitis or keratitis, can happen when the eyes are rubbed after touching the lesion. Finger infection (herpetic whitlow) can occur when a child with cold sores or primary HSV-1 infection sucks his/her fingers.
Docosanol, a saturated fatty alcohol, is a safe and effective topical application that has been approved by the United States Food and Drug Administration for herpes labialis in adults with properly functioning immune systems. It is comparable in effectiveness to prescription topical antiviral agents. Due to its mechanism of action, there is little risk of drug resistance.[11] The duration of symptoms can be reduced by a small amount if an antiviral, anaesthetic or non-treatment cream (such as zinc oxide or zinc sulfate) is applied promptly.[12] Effective antiviral medications include acyclovir[13] and penciclovir, which can speed healing by as much as 10%.[14] Famciclovir or valaciclovir, taken in pill form, can be effective using a single day, high-dose application and is more cost effective and convenient than the traditional treatment of lower doses for 5–7 days.[15]
Lysine has been suggested as a treatment for herpes labialis based on in vitro studies, but the evidence is inconclusive in humans.[16]
Avoiding touching an active outbreak site, washing hands frequently while the outbreak is occurring, not sharing items that come in contact with the mouth, and not coming into contact with others (by avoiding kissing, oral sex, or contact sports) can reduce the likelihood of the infection being spread to others.[5]
Because the onset of an infection is difficult to predict, lasts a short period of time and heals rapidly, it is difficult to conduct research on cold sores. Though famciclovir improves lesion healing time, it is not effective in preventing lesions; valaciclovir and a mixture of acyclovir and hydrocortisone are similarly useful in treating outbreaks but may also help prevent them.[14]
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