Serpiginous pemphigus, also known as herpes zoster, is caused by varicella-zoster virus infection. If there is a breakout, bathing is not recommended so as not to induce infection when the trauma comes in contact with water and cause the rash to worsen. If there is no trauma and the lesions have dried, you can take a bath, because serpiginous herpes is mainly a viral invasion of the nerves. Treatment can be oral antiviral treatment with vaxilovir, usually 0.3g, taken orally twice a day on an empty stomach for 7-10 days, preferably within three days of the appearance of the rash, for best results. If the rash has been present for a week, there is little point in taking antiviral drugs orally, and at the same time you can take vitamin B1, B6, B12 and vitamin E orally with nerve nutrition.