First of all, there is no such thing as a flat wart, but it is usually referred to as a flat wart. Flat warts are a common benign superfluous epidermis caused by human papilloma virus infection. It is true that flat warts tend to occur on areas like the face, back of the hands, and forearms. There is no specific reason why warts occur on the face, but there are often small wounds on the face through which the human papillomavirus can invade the skin, leading to the appearance of these benign growths. The flat warts are somewhat different in appearance from the so-called common warts, mostly due to the different typing with the human papilloma virus that causes this disease. Flat warts are mostly caused by HPV-3, but like common warts are mostly caused by HPV-2.