Herpes labialis | |
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Synonyms | fever blisters, herpes simplex labialis, recurrent herpes labialis, orolabial herpes |
Herpes labialis of the lower lip. Note the blisters in a group marked by an arrow. | |
Classification and external resources | |
Specialty | Infectious disease |
ICD-10 | B00.1 |
ICD-9-CM | 054.9 |
MeSH | D006560 |
Herpes labialis, also known as cold sores, is a type of herpes simplex infection affecting the lips. An outbreak of herpes labialis is caused by infection of the lips by the herpes simplex virus (HSV) and typically causes small blisters or sores on or around the mouth. The sores typically heal within 2–3 weeks, but the herpes simplex virus remains dormant in the facial nerve branches. After infection of the facial nerve, the virus periodically reactivates to create sores in the same area of the mouth or face at the site of the original infection.
Cold sore recurrences range from rare episodes to 12 or more episodes per year. People with the condition typically experience one to three attacks each year. The frequency and severity of outbreaks generally decrease over time.
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 usually show no symptoms; when symptoms do appear they typically resolve within two weeks. 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.
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). Primary HSV infections in adults often results in pharyngitis similar to that observed in glandular fever (infectious mononucleosis), but gingivostomatitis is less likely.