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Herpes Labialis (Cold Sore)

This is an infection, which is produced by the Herpes Simplex Virus. It is characterised by an eruption of small and usually painful blisters on the skin of the lips, mouth, gums, or the skin around the mouth.

Causes
Infection of the mouth with Herpes Simplex Type 1 virus. The virus is very contagious. Contact can occur directly, through contact with towels, dishes, etc. It can also produce congenital abnormalities in the foetus.

Incidence
It has been estimated that 80% of the population have been infected by HSV type 1 by the age of 20.

Symptoms
The initial infection may produce no symptoms or may produce mouth ulcers. The virus remains in the sensory ganglion and is latent.

In some people the virus reactivates and produces recurrent cold sores at or near the original site of the infection.

Recurrence may be triggered by:

• Common Cold
• Mechanical Trauma
• Stress
• Menstruation
• Sun exposure, UV light

Warning Symptoms of itching, burning, or tingling may occur about 2 days before lesions appear.

Skin lesions form around the lips, mouth.

Small blisters fill with a clear yellowish fluid. These blisters form on red, painful skin areas. They break and ooze. Yellow crusts slough to reveal pink’ healing skin.

The lesions of Herpes Labialis last for 7 to10 days, then begin to resolve.

Prevention
Avoid contact with cold sores. Do not share items with infected persons. Avoid sun exposure if prone to oral herpes.

Tests
Diagnosis is made on appearance &/or culture.

Viral culture on baby hamster kidney (BHK) cells or Tzanck test of skin lesion can be used.

Electron microscopy is also useful.

Treatment
Untreated symptoms will reside in 1 to 2 weeks.

Acyclovir (5%) may reduce the duration if applied topically (every 4 hours for 5 days) during the prodromal phase.

Complications
Generalised infection may be life threatening in the immunocompromised eg. Cancer, HIV, atopic dermatitis.

Other problems include secondary skin infections, blindness or spread to other skin areas.