唇疮，学名复发性唇疱疹，是出现于嘴唇或鼻孔边缘的感染，由具有传染性的单纯疱疹病毒一型病毒所引起。唇疮出现初期，患处会出现痕痒和灼热，然后出现水泡，之后会演变成溃疡。

• 口疮
• 单纯疱疹
• 疱疹

Herpes labialis, also called cold sores among other names, is a type of herpes simplex occurring on the lip, i.e. an infection caused by herpes simplex virus (HSV). An outbreak typically causes small blisters or sores on or around the mouth. The sores typically heal within 2–3 weeks, but the herpes virus remains dormant in the facial nerve branches, following orofacial infection, periodically reactivating (in symptomatic people) to create sores in the same area of the mouth or face at the site of the original infection.