口唇疱疹为单纯性疱疹病毒所引起。单纯性疱疹病毒初次侵入人体发生感染时,大多发生在6个月至5岁的小儿。到了成人,由于绝大多数已受过感染,因此,他们绝大部分,(在90%以上)的血液中都存在有单纯性疱疹的抗体。初次感染时,病毒侵入人体的部位,大多数在口咽粘膜,少数在阴道、阴蒂、宫颈、包皮、龟头、冠状沟、角膜、食道粘膜及皮肤等处。患者大多无症状,少数可有轻或重的局部或全身症状。局 Cold sores are caused by herpes simplex virus. Herpes simplex virus first invaded the human body when an infection occurs, mostly in children from 6 months to 5 years of age. As adults, the vast majority of them are already infected, so most of them (more than 90%) have antibodies to herpes simplex. The first infection, the virus invades the body parts, most of the oropharyngeal mucosa, a few in the vagina, clitoris, cervix, foreskin, glans, coronal, corneal, esophageal mucosa and skin and so on. Most patients are asymptomatic, a few may have mild or severe local or systemic symptoms. Bureau