Skin warts
Some HPV infections can cause warts (verrucae), which are noncancerous skin growths. Infection with these types of HPV causes a rapid growth of cells on the outer layer of the skin.] Types of warts include:
Common warts: Some "cutaneous" HPV types cause common skin warts. Common warts are often found on the hands and feet, but can also occur in other areas, such as the elbows or knees. Common warts have a characteristic cauliflower-like surface and are typically slightly raised above the surrounding skin. Cutaneous HPV types can cause genital warts but are not associated with the development of cancer.
Plantar warts are found on the soles of the feet. Plantar warts grow inward, generally causing pain when walking.
Subungual or periungual warts form under the fingernail (subungual), around the fingernail or on the cuticle (periungual). They may be more difficult to treat than warts in other locations.
Flat warts: Flat warts are most commonly found on the arms, face or forehead. Like common warts, flat warts occur most frequently in children and teens. In people with normal immune function, flat warts are not associated with the development of cancer.
Genital warts are quite contagious, while common, flat, and plantar warts are much less likely to spread from person to person.
Genital warts
Genital or anal warts (condylomata acuminata or venereal warts) are the most easily recognized sign of genital HPV infection. Although a wide variety of HPV types can cause genital warts, types 6 and 11 account for about 90% of all cases.
Most people who acquire genital wart-associated HPV types clear the infection rapidly without ever developing warts or any other symptoms. People may transmit the virus to others even if they do not display overt symptoms of infection.
HPV types that tend to cause genital warts are not those that cause cervical cancer. Since an individual can be infected with multiple types of HPV, the presence of warts does not rule out the possibility of high-risk types of the virus also being present.
The types of HPV that cause genital warts are usually different from the types that cause warts on other parts of the body, such as the hands or inner thighs.
Respiratory papillomatosis
HPV types 6 and 11 can cause a rare condition known as recurrent respiratory papillomatosis, in which warts form on the larynx or other areas of the respiratory tract.
These warts can recur frequently, may require repetitive surgery, may interfere with breathing, and in extremely rare cases can progress to cancer.
In the immunocompromised
In very rare cases, HPV may cause epidermodysplasia verruciformis in immunocompromised individuals. The virus, unchecked by the immune system, causes the overproduction of keratin by skin cells, resulting in lesions resembling warts or cutaneous horns.
For instance, Dede Koswara, an Indonesian man developed warts that spread across his body and became root-like growths. Attempted treatment by both Indonesian and American doctors included surgical removal of the warts.