When is antiviral treatment recommended for cold sores?

Cold sores, also called herpes labialis or fever blisters, are caused by herpes simplex virus. A tingling, burning, or itching feeling can appear before blisters. Prescription antiviral medicine works best when used early, and a clinician may suggest treatment for a troublesome outbreak or a preventive plan when episodes keep returning. The medicine does not remove the virus from the body. Some sores heal with simple comfort measures, but a new or uncertain facial rash still deserves a proper diagnosis.

Use prescribed medicine according to the instructions and begin it at the first warning sign if your clinician has given you an episodic plan. Wash hands after touching the area, avoid kissing and oral sex while a sore is present, and do not share cups, towels, lip products, or razors. Protect cracked lips with a suitable balm and seek advice before treating a sore close to the eye.

Arrange medical review for sores that are unusually extensive, very painful, repeatedly returning, slow to heal, or accompanied by fever or feeling unwell. Seek urgent assessment for eye pain, light sensitivity, reduced vision, or blisters on the eyelid. Prompt advice is also needed when immune defenses are weakened or when the diagnosis is unclear.

Ask whether the sore is herpes simplex, when to start treatment, whether a preventive prescription is suitable, how to protect a partner or family member, and which symptoms mean the eye needs urgent assessment.