Cold Sores & Oral Herpes — Outbreaks, Triggers & Treatment

Primary vs recurrent infection

Primary HSV infection (usually in childhood) presents as primary herpetic gingivostomatitis — fever, lymphadenopathy and multiple painful intra-oral and perioral ulcers — and is treated supportively with oral acyclovir within the first 72 hours. Once the primary infection resolves, the virus lies latent in the trigeminal ganglion and recurs as cold sores under specific triggers.

Treatment

Antivirals shorten outbreaks if started early; suppressive therapy is offered to patients with frequent recurrences.

• Topical acyclovir / penciclovir cream at first tingle
• Oral acyclovir, valacyclovir or famciclovir for severe / frequent outbreaks
• Suppressive valacyclovir 500 mg daily for >6 episodes/year
• Sunscreen lip balm to prevent UV-triggered recurrences
• Avoid touching the lesion; cold sores are highly contagious

Why timing of antivirals is everything

Antivirals work by interrupting viral replication. Maximal benefit is in the prodrome — the tingle or burn 12–24 hours before any blister appears. Once blistering is established, antivirals still shorten the episode but by less. Patients with frequent outbreaks should carry the prescription with them.

Protecting others — and yourself — during an outbreak

Cold sores are highly contagious from the prodrome until the lesion crusts. Avoid kissing, oral sex (HSV-1 increasingly causes genital herpes), sharing utensils, lip balm or towels. Wash hands after touching the lesion to avoid autoinoculation to the eye (herpetic keratitis is an ophthalmic emergency).