Types
A range of types of wart have been identified, varying in shape and site affected, as well as the type of human papillomavirus involved. These include:

Common wart (verruca vulgaris), a raised wart with roughened surface, most common on hands, but can grow anywhere on the body. Sometimes known as a Palmer wart or Junior wart. Flat wart (verruca plana), a small, smooth flattened wart, flesh-coloured, which can occur in large numbers; most common on the face, neck, hands, wrists and knees. Filiform or digitate wart, a thread- or finger-like wart, most common on the face, especially near the eyelids and lips. Genital wart (venereal wart, condyloma acuminatum, verruca acuminata), a wart that occurs on the genitalia. Periungual wart, a cauliflower-like cluster of warts that occurs around the nails. Plantar wart (verruca, verruca plantaris), a hard, sometimes painful lump, often with multiple black specks in the center; usually only found on pressure points on the soles of the feet. Mosaic wart, a group of tightly clustered plantar-type warts, commonly on the hands or soles of the feet. Cause
Warts are caused by the human papilloma virus (HPV). There are about 130 known types of human papilloma viruses. HPV infects the squamous epithelium, usually of the skin or genitals, but each HPV type is typically only able to infect a few specific areas on the body. Many HPV types can produce a benign growth, often called a "wart" or "papilloma", in the area they infect. Many of the more common HPV and wart types are listed below.
Common warts – HPV types 2 and 4 (most common); also types 1, 3, 26, 29, and 57 and others. Cancers and genital dysplasia – "high-risk" HPV types are associated with cancers, notably cervical cancer, and can also cause some vulvar, vaginal, penile, anal and some oropharyngeal cancers. "Low-risk" types are associated with warts or other conditions.High-risk: 16, 18 (cause the most cervical cancer); also 31, 33, 35, 39, 45, 52, 58, 59, and others.Plantar warts (verruca) – HPV type 1 (most common); also types 2, 3, 4, 27, 28, and 58 and others. Anogenital warts (condylomata acuminata or venereal warts) – HPV types 6 and 11 (most common); also types 42, 44 and others.Low-risk: 6, 11 (most common); also 13, 44, 40, 43, 42, 54, 61, 72, 81, 89, and others.Verruca plana (flat warts) – HPV types 3, 10, and 28. Butchers warts – HPV type 7. Hecks disease (focal epithelial hyperplasia) – HPV types 13 and 32. Pathophysiology
Common warts have a characteristic appearance under the microscope. They have thickening of the stratum corneum (hyperkeratosis), thickening of the stratum spinosum (acanthosis), thickening of the stratum granulosum, rete ridge elongation, and large blood vessels at the dermoepidermal junction. Diagnosis
On dermatoscopic examination, warts will commonly have fingerlike or knoblike extensions. Prevention
Gardasil 6 is an HPV vaccine aimed at preventing cervical cancers and genital warts. Gardasil is designed to prevent infection with HPV types 16, 18, 6, and 11.