Treatment of lichen planus with dactin usually requires 2-5 weeks of medication and should be continued for about 10 days even after the symptoms have disappeared to prevent the possibility of recurrence. Lichen planus, commonly known as sweat spot, is a superficial fungal infectious skin disease caused by Malassezia infection of the epidermal stratum corneum. Dacronin, also known as imidazole nitrate cream, is clinically useful in the treatment of lichen planus, and the efficacy of dacronin is more precise and lichen planus is more easily cured. Since lichen planus occurs more often in the summer and is prone to recurrence, you should continue using the medication for about 10 days even after the symptoms disappear to reduce the possibility of recurrence. In addition, you can also prevent lichen planus in summer by applying dacrynic acid or selenium disulfide. For patients who love to sweat, you should bathe and change clothes regularly, and items that touch the skin such as sheets, towels, and clothes should be dried and disinfected frequently, etc. The diet should be light so as not to consume too spicy food to stimulate the recurrence of the disease.