The hand grows flat warts because the human papilloma virus infects the skin of the hand caused by. Flat warts are caused by the human papilloma virus entering the epithelial cells (especially the basal cells) through tiny breaks in the skin and mucous membranes and replicating and proliferating, leading to abnormal differentiation and proliferation of the epithelial cells, causing benign epithelial superfluous organisms (objects protruding out of the skin), which are a kind of warts. Flat warts mostly occur in the face, back of the hands and forearms, etc., the damage is often a large number of flat small papules, usually no conscious symptoms, sometimes itchy. The course of the disease is chronic and can affect aesthetics. Of all HPV infections, flat warts have the highest incidence of spontaneous remission, most often resolving on their own after 2 to 3 years or more. According to the patient’s medical history and skin lesion manifestations, combined with the results of acetic acid white test and pathology examination, the diagnosis can usually be clearly defined. Treatment is generally based on topical medication, including salicylic acid and retinoic acid ointment, etc. It can also be treated by liquid nitrogen freezing and surgical excision. If you feel unwell, you should go to the hospital in time to avoid delaying your condition or causing adverse reactions.