Overview
Herpes simplex labialis—also known as cold sores or fever blisters—is a disorder caused by a virus of the family Herpesviridae. Herpes simplex virus 1 (HSV-1) is primarily associated with oral and labial lesions, whereas herpes simplex virus 2 (HSV-2) is usually involved in producing genital sores. However, preference of a specific HSV type for an anatomic site is changing, in part owing to varying sexual practices. Also, any of the human herpes viruses (cytomegalovirus, Epstein-Barr virus, and others)—not just HSV-1 and 2—can cause oral lesions.
Etiology
- HSV is contagious and is believed to be transmitted by direct contact (e.g., kissing or sharing utensils or drinks). The virus enters the host through a break in the skin or intact mucous membranes.
- Fluid from herpes vesicles contains live virus and may serve to transmit the virus from patient to patient.
- Because the virus remains viable on surfaces for several hours, contaminated objects also may be a source of infection.
- Fluid from herpes vesicles contains live virus and may serve to transmit the virus from patient to patient.
- Once the virus has infected a host, it remains in a latent state in the trigeminal ganglia. The virus can be reactivated upon exposure to a trigger such as ultraviolet radiation, stress, fatigue, cold, and windburn.
- Other possible triggers include fever, injury, menstruation, dental work, infectious diseases, and factors that depress the immune system (e.g., chemotherapy and radiation therapy).
- Although the virus can go through periods of dormancy and reactivation, the person is infected for life. Upon reactivation, the lesions often arise repeatedly in the same location.
Signs and Symptoms
- Herpes simplex labialis is so named because it commonly occurs on the lip or on areas bordering the lips; the usual site is at the junction of mucous membrane and skin of the lips or nose. However, these lesions may also occur intraorally (primarily involving keratinized mucosa such as hard palate or gingiva).
- Herpes simplex labialis lesions are recurrent, painful, and cosmetically objectionable.
- The lesion first becomes visible as small, red papules of fluid-containing vesicles 1–3 mm in diameter. Often, many lesions coalesce to form a larger area of involvement.
- An erythematous, inflamed border around the fluid-filled vesicles may be present.
- A mature lesion often has a crust over the top of many coalesced, burst vesicles; its base is erythematous.
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- The lesion first becomes visible as small, red papules of fluid-containing vesicles 1–3 mm in diameter. Often, many lesions coalesce to form a larger area of involvement.
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