Sweat patches, also known as lichen planus, are superficial infections caused by Malassezia bacteria that invade the stratum corneum of the skin. Sweat patches are harmful to the body, and the hazards it causes to the body mainly include affecting aesthetics, infecting oneself or infecting others. 1. Affecting aesthetics: lichen planus is a superficial fungal infectious disease that occurs on the skin surface, which is manifested as small light brown or brownish plaques on the skin surface, with a small amount of scales on the surface, which will seriously affect the aesthetics. 2. Self-infection: lichen planus can be infected in other parts of the body through scratching, leading to an increase in the scope of lesions. 3. Infection to other people: fungal infection can be spread from person to person through close contact or contact with household items contaminated by the patient. Patients with lichen planus are advised to consult the doctor in time, follow the doctor’s instructions for standardized treatment, and avoid unauthorized use of medication.