Lichen planus is a skin disease that occurs on the surface skin of the body due to a certain type of fungal infection, mostly in areas that sweat a lot, such as the underarms and back. Lichen planus is actually caused by a fungus called Malassezia and is contagious to some extent, but the chances are not high. It is usually transmitted through contact, such as direct contact with the affected area or clothing. In this regard, care should be taken to avoid frequent contact with the affected area of the patient and to disinfect his or her clothing. The factors that lead to lichen planus include weakness, poor nutrition, and diabetes. The disease is characterized by a rash that starts out near the pores and gradually expands, with a clear border with the surrounding skin and scales that fall off the affected area. It may appear on the back or abdomen and shoulders where there is a lot of sweating. For lichen planus, medication is currently available, such as the use of certain lotions to clean the affected area and directly kill the epidermal fungus. This is combined with the use of some applied ointments to help recovery. In addition, oral medication can also be used for severe cases. It is important to take precautions to ensure that the body is well nourished, to avoid physical weakness, and to take a bath in time after sweating to clean off sweat stains to avoid infection. It is not likely that ringworm is caused by fungus, but it is somewhat contagious, so it is important to avoid frequent direct contact with the affected area and to treat and prevent it.