The fundamental cause of flat warts is due to viral infection, primarily by the human papillomavirus (HPV). Flat warts can be transmitted through direct or indirect contact and can spread between individuals, especially when there are skin lesions or injuries, which make it easier to contract. After contracting flat warts, it is recommended to seek timely treatment, which can be administered through laser or cryotherapy. It is important to maintain hygiene and cleanliness, avoiding sharing towels, bath towels, etc., with others.