Warts are a common skin infection. They are caused by the human papilloma virus (HPV). This virus gains entry to the skin through tiny breaks in the skin and lives in the outermost layer of the skin. Growth of the virus produces a bump with the characteristic rough, granular appearance. They are usually slightly lighter or darker than the color of the skin and sometimes have black dots in them. The dots are small clotted blood vessels at the base of the wart. Most often warts appear on the hands and feet but the virus can occur on any part of the body, including the face.

An HPV vaccine has been developed which works by preventing the most common type of human papilloma viruses that cause cervical cancer and genital warts. The vaccine is recommended for preteen girls and boys at age 11 or 12—before they become sexually active.

Warts are not usually a major health concern. (The primary exception would be genital warts–see below.) Eventually they often will disappear on their own, although this can take years or even decades. Moreover, they can be painful when they occur on the hands and feet and can be embarrassing when they occur on visible parts of the body.

What causes warts and how are they spread?

As stated above, warts result from exposure to HPV virus. Unfortunately, this is a very common virus to which we are all frequently exposed. The virus is found on many common surfaces, such as shower floors. It is also shed from the surface of warts, explaining the contagious nature of warts and their ability to spread.

Like most viruses, different people have different susceptibility to warts. Some people are, in fact, relatively immune and do not get warts. Other people get them frequently and severely. It is also believed that many children and young adults develop immunity to warts, which is why they are not as common among adult populations.

How to help prevent warts?

Don't go barefoot in public places, especially in pools and locker rooms. Don't pick at warts or try to peel them off, as this will only spread the virus. Have separate nail clippers for healthy and infected areas. Try not to shave over warts. Try not to touch other people's warts.

What are the different kinds of warts?

The two most common kinds of warts are known as common warts and plantars warts. However, the HPV virus can also occur on the sexual organs and they are known as genital warts.

Common warts—usually they appear near the fingernails and on the hand. Children and adolescents are most often affected. They most commonly appear where the skin is broken, such as where fingernails are bitten or picked.

Plantars warts—or foot warts are usually on the soles of the feet. Unlike common warts, plantars warts are usually less bumpy because the pressure of walking, keeps them flat. Plantars warts can sometimes be painful, when pressured by movement in a shoe.

Genital warts—occur in the genital area and on the sexual organs. Genital warts are considered to be a sexually transmitted disease. This is the only type of wart considered to be a serious health issue. This is because the HPV virus can develop into cervical cancer in women and (less commonly) into penile cancer in men. The HPV virus is responsible for at least 95 percent of cervical cancers. The HPV virus can also be transmitted to a newborn during birth.

How are warts treated?

Although warts can be stubborn, annoying and persistent, many will disappear over time on their own or with simple over the counter medications. You should see your dermatologist if warts are spreading, appear on the genitals or if you have been unsuccessful at treating them.

Some of the medical treatments for warts are:

OTC Treatments—it is important to seek the advice of a dermatologist before using OTC wart treatments if you are unsure of the diagnosis. When deciding to try the self-care approach with warts, there are several products available on the market. The most effective products have the ingredient, salicylic acid, which works by drying up the wart and sloughing off the skin. It is important to treat only the wart, since these products can irritate surrounding skin.

Freezing (cryotherapy)—this method can destroy a wart by freezing it with liquid nitrogen. As the skin thaws, the dead skin (the wart) falls off. This method is effective but can sometimes require multiple treatments.

Electrodesiccation and curettage—this treatment involves cutting away the wart or destroying the wart by using an electric needle.

Laser surgery—the laser emits a narrow beam of light that helps to vaporizes HPV growths. A certain type of laser light helps vaporize the blood vessel that supplies the wart.

HPV vaccines— Two HPV vaccines are licensed by the FDA and recommended by CDC. These vaccines are Cervarix (made by GlaxoSmithKline) and Gardasil (made by Merck).

Injections—medication injections such as the anti cancer drug bleomycin can be injected into the wart to kill the virus.

Warts can be stubborn and hard to treat. At times, multiple treatments or more than one approach may be needed to treat them successfully. Moreover, when standard remedies fail, experienced dermatologists have other treatments that can be very effective for recalcitrant warts. These include cantharone, immunotherapy and others.