For today’s morninghuddle, we’ll back track to some information that you learned in dental school. Our hot topic: recurrent herpes labialis or more commonly known as cold sores. Caused by HSV-1 (herpes simplex virus type-1 and less frequently type 2), herpes labialis is characterized by it’s eight stages: Prodrome, erythema, papule, vesicle, ulcer/soft crust, hard crust, dry flake, and residual swelling.
Recurrent herpes labialis is common occuring in 20-40% of the population and can be quite the nuisance with symptoms of pain and unsightly blisters that episodically reoccur numerous times a year. After primary infection the virus can remain dormant in sensory ganglion or skin epithelium, evading immune surveillance. Viral replication can be triggered by sunlight, stress, menses, trauma, or illness. Vesicles develop within hours and present the highest infectivity period within the first 24 hours of the appearance of the lesion.
Management
Topical Acyclovir came into use in the 1980’s. ACV distrupts viral DNA synthesis by terminating chain elongation and replication of HSV. Acyclovir has a high selectivity and is only active in virally infected cells, minimizing toxicity to other cells. 5% acyclovir cream may be efficacious in reducing the duration of lesions especially if applied early in the prodrome stage. Additional anti-inflammatory agents may enhance it’s effectiveness.
Oral Acyclovir may be taken at 200 – 400mg daily over the course of 5 days to treat RHL, and may reduce healing time and pain by 1-1.5 days especially if started in early stages.
Valacyclovir is a acyclovir with an addition of an ester group. It is well absorbed by the GI tract and thus has a higher bioavailability as compared to acyclovir. Valacyclovir at 1000mg twice a day may abort leisons.
Penciclovir also works by inhibiting viral DNA polymerase by acting on the viral thymidine kinase. It’s high specificity for virally infected cells and prolonged half life in the HSV infected cell makes it an attractive remedy for RHL. 1% penciclovir cream is effective in reducing the pain and duration of the lesion.
Topical docosanol inhibits viral replication by interfering with viral entry into target cells. Mechanisms is poorly understood. 10% docosanol cream is effective in reducing healing time and pain of RHL.
Other forms of antivirals commonly used for treatment of RHL is famcicylovir. Lysine supplementation has little effect compared to placebos. Zinc deficiency may be linked to longer duration and exasperation of symptoms experienced with RHL. Sun screen alone can reduce the incidences of RHL. Herpes labialis is irritating (really!), but with proper management we can help our patients get over it.
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