Brown spots on the chest, consider the possibility of pityriasis pilaris. Pityriasis furfur is commonly known as sweat spot, is the skin disease caused by fungal infection of the skin, generally seen in young and strong men, good in sebaceous glands secretion location, such as the forehead, back and other trunk location, patients generally have no conscious symptoms, part of the people can have mild itching. The lesions are initially pore-centered, raindrop-like in appearance, and later will gradually expand and even fuse with each other to form a sheet. Some patients have brown or light brown lesions, but there will be fine scales on the surface of the lesions, and this disease is particularly prone to recurrence, so generally after the disease is controlled, regular topical use of 2% ketoconazole lotion can prevent recurrence.