The initial appearance of flat warts is mainly characterized by slightly elevated flat papules and so on. Flat warts are caused by human papillomavirus infection and are most common on the face and back of the hands. The initial appearance of flat warts is mainly manifested as sesame seed or rice grain size, slightly elevated in the skin surface of the flat papules. The shape is round or oval, and the surface of the lesion is smooth and hard. The color of the skin is normal skin color, light brown, gray and so on. In addition, most patients with flat warts will have strips or beads of papules along the distribution of the scratch marks after scratching the affected area. If the above symptoms occur, it is considered to be related to flat warts, and it is recommended to go to the regular hospital for relevant examination and treatment.