Causes and Types of Warts

Warts, caused by the human papillomavirus or HPV, are noncancerous skin growths. They form when the virus invades the skin, usually through a tiny cut or scratch. The virus causes rapid growth of cells on the outer layer of skin. Warts are usually skin-colored but can be dark. They can be rough or smooth.

Here are the types of skin warts, known medically as verrucae:

• Common warts are found on the fingers, and the backs of the hands
• Palmer warts are found on the palms, as the name suggests.
• Plantar warts grow on the feet, typically the soles
• Flat warts are typically smaller and smoother than other warts; they can grow in large numbers, even as much as 20 to 100 at a time. Flat warts on children are typically found on the face.
• Filiform warts look like the kind that cartoon witches get on their chins or noses and stick straight out. They are often found on the face.

Genital warts don’t typically affect younger children because they are usually sexually transmitted.