Warts are skin growths that are caused by the human papillomavirus (HPV). There are more than 100 kinds of HPV, some of which can cause warts on the skin. HPV stimulates quick growth of cells on the skin's outer layer. In most cases, common warts appear on the fingers, near the fingernails, or on the hands. Certain types of HPV can cause warts to appear in the genital area.
Warts are caused through direct contact with HPV, which is contagious. HPV may spread by person-to-person contact or through direct contact with an object used by a person with the virus. The virus that causes warts also can spread to other places on the body of the person with warts.
Types of Warts
- Plantar warts: This type of wart usually appears as a flesh-colored or light brown lump flecked with small clotted blood vessels that look like tiny black dots. Plantar warts affect the soles of the feet.
- Genital warts: Genital warts can appear in the pubic area, on the genitals, in or around the anus, and/or in the vagina. They look like small flesh-colored, pink, or red growths. The warts may look similar to the small parts of a cauliflower, or they may be very tiny and difficult to see. They often appear in clusters of three or four, and may grow and spread rapidly. They usually aren't painful, although they may cause mild pain, bleeding, and itching. HPV infection is the most common sexually transmitted disease in North America. Certain forms of the virus can cause cervical cancer.
- Flat warts: This type of wart is more common in teens and children than in adults. Flat warts are smoother, flatter, and smaller than other warts, and they generally occur in groups on your face. Flat warts also can appear on the legs, especially among girls and women.
How Are Warts Treated?
In most cases, warts on the skin are harmless and may go away without treatment. That includes flat warts, though they may take a few months or even years to go away. However, genital warts should be evaluated by a doctor.
Warts sometimes come back after treatment, and you may need more than one type of treatment. Although doctors try to clear warts quickly, most methods to remove them require multiple treatments. Treatments include:
- Freezing (cryotherapy): This can be done with over-the-counter freezing spray products or by your doctor, who will use liquid nitrogen to freeze the wart. With the at-home treatment, temperatures can reach as low as a negative 100 degrees. The downside of home treatment is that it may not freeze the wart deeply enough to be effective. It can also be painful, since the spray needs to be applied longer than a freezing treatment you'd get in a doctor’s office. When it works, a blister forms around the wart and the dead tissue falls off within 1-2 weeks.
- Cantharidin: This substance is made with an extract of a blister beetle. It's applied to the skin and forms a blister around the wart. Then the area is covered with a bandage. The blister lifts the wart off the skin.
- Other medications: These include bleomycin, which is injected into a wart to kill the virus that causes it, and imiquimod (Aldara, Zyclara), an immunotherapy drug that stimulates your immune system to fight off the wart virus. It comes as a prescription cream. Although imiquimod is approved for genital warts, it can also work fairly well on other types of warts.
- Salicylic acid: Over-the-counter wart treatments come in several forms (gel, ointments, or pads) and have salicylic acid as their active ingredient. When you apply the treatment on a regular basis, the acid gradually dissolves the wart tissue. The process may take several weeks. This is not for use on genital warts.
- Minor surgery: When warts can't be removed by other therapies, a doctor can do surgery to cut away the wart. They'll destroy the base of the wart using an electric needle or by cryosurgery (deep freezing).
- Laser surgery: This procedure uses an intense beam of light (a laser) to burn and destroy wart tissue.
Can Warts Be Prevented?
If you already have warts, you can prevent them from spreading by not picking at them. Consider covering warts with bandages. In addition, keep your hands as dry as possible. Warts are harder to control in moist environments. Never brush, comb, or shave areas where you have warts, since this can cause the virus to spread. Wash your hands thoroughly after touching any warts.
To prevent genital warts, some of the steps you can take include: