Oral Disease: Herpes Labialis

What Causes Herpes Labialis?

Herpes simplex virus (HSV), after primary oral or perioral infection, remains latent in the trigeminal ganglion. HSV moves down the trigeminal nerve to produce mucocutaneous lesions if reactivated by factors such as:

• fever
• sunlight
• trauma or
• immunosuppression.

Labial or perioral herpes labialis (cold sores) affect up to 15% of the normal population.

What are the Symptoms?

Lesions are seen typically at the mucocutaneous junction, starting as macules which rapidly become papular, vesicular, then pustular over a few days and crust and heal usually without scarring. Any  mucocutaneous site can be affected, including the anterior nares.

Patients with T-cell immune defects in particular are predisposed to recurrent herpes with widespread and persistent lesions. Haemorrhage into lesions produces a deceptive appearance in a leukaemic or other patient with thrombocytopenia.

Impetigo can mimic (or complicate) herpes labialis.

How is Herpes Labialis Diagnosed?

Differential diagnosis of herpes labialis is mainly from primary HSV infection, herpes zoster, impetigo or carcinoma (rarely). Diagnosis is largely clinical, though polymerase chain reaction DNA detection, immunodetection, electron microscopy or viral culture is occasionally needed.

How is Herpes Labialis Treated?

Most patients will have spontaneous remission within 1 week to 10 days but, as the condition is both uncomfortable and unsightly, antiviral treatment is indicated from as early in the disease as possible. Penciclovir 1% cream applied in the prodrome may help abort or control lesions in healthy patients,
and appears more effective than aciclovir 5% cream.

Systemic antivirals (aciclovir, valaciclovir and famciclovir) may be needed for more severe cases, especially immunocompromised patients, in whom the lesions may otherwise spread or persist. Antiviral resistance is becoming a significant problem to immunocompromised persons, especially those with severe immune defects: alternative therapies then include foscarnet, n -docosanol, idoxuridine or tromantadine hydrochloride.

Reference : Scully R. 2010. Oral and Maxillofacial Disease. Informa Healthcare. UK