Filiform warts and flat warts are different; their commonality is that both belong to viral warts, which are benign growths caused by the human papillomavirus (HPV) infecting the skin and mucous membranes. Clinically, they are caused by different subtypes of HPV, and their appearances are distinct. Filiform warts are caused by HPV type 2, characterized by elongated, protruding growths with a keratinized tip, hence the name filiform warts. On the other hand, flat warts are often caused by HPV type 3, commonly found on the face, backs of hands, and forearms. These lesions are flat, slightly raised papules, circular or oval-shaped, with a smooth, hard surface and are naturally skin-colored or light brown. They usually appear suddenly, in large numbers, and are densely packed.