Herpes simplex is caused by human herpes simplex virus infection, which often occurs after fever. At first, it was erythema, and then on the basis of erythema, groups of blisters the size of needles appeared, usually one group, but also two or three groups. After rupture, the surface rotted and gradually dried and scabbed.

Herpes simplex occurs at the junction of skin and mucosa, especially on the face and genitals. Recurrent patients tend to be in the same place. The patient felt a local burning sensation and itching. When the rash appears, the local lymph nodes are swollen. The course of disease is usually 1~2 weeks, which can heal itself. But it is easy to relapse, and there is no scar after cure.