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Warts are small, rough, rounded growths on the top layer of the skin. They may appear alone or in clusters. Common warts are caused by the human papillomavirus (HPV) and are contagious through direct contact. Warts, although benign, can easily spread to other parts of the body without treatment.
What are warts?
Warts, also called common warts or verrucae, are small, rough, rounded growths on the top layer of the skin. They may appear alone or in clusters. Common warts are caused by the human papillomavirus (HPV) and are contagious through direct contact. They may spread from one place on the body to another simply through touch.
Warts often first appear on the hands and fingers, especially near the nails or after any injury to the skin. This is why biting fingernails is a risk factor for warts.
Warts are benign, meaning they are not cancerous. But they can be unsightly and interfere with normal use of the hands, so treatment is often beneficial through a few different methods of removal.
You can try several over-the-counter treatments, including salicylic acid and cryotherapy (freezing). All of this said, most warts go away on their own, but less so in adults.
Warts usually appear as one or more bumps on the skin. The color, appearance, and location of warts vary depending on the type of wart. Examples of specific types of warts include:
- Common wart: These warts often appear on the hands or knees, and usually look like rough, skin-colored, raised bumps with a flat top and possibly small black dots on the surface.
- Plantar wart: These warts appear on the soles of the feet, and usually look like rough, skin-colored, flat bumps with small red spots on the surface. They may interrupt the normal skin lines of the feet.
- Flat wart: These warts often appear on the face, arms, legs, or back of the hands, and usually look like small smooth, skin-colored, flat-topped bumps.
- Anogenital wart: These warts appear near the anogenital area. They may be skin-colored, red, purple, or brown, and can have a variety of shapes, including flat, round, raised, or even "cauliflower-shaped." They are usually soft when pressed upon.
Other symptoms often associated with warts include the following.
- Itching: Most warts do not itch, but in some cases may be mildly itchy.
- Pain or discomfort: Most warts are not painful. However, in some cases, warts may cause pain or discomfort, especially if they are large or near a sensitive area.
- Difficulty with urination or defecation: In rare cases, large anogenital warts may cause difficulty with urination or defecation. This can occur if they block or cause disfigurement of the anogenital area.
- Shame and anxiety: Warts, especially anogenital warts, can cause shame and anxiety. People may feel that having warts causes a form of stigmatization, and they may be worried about the risk of developing cancer.
What causes a wart?
Warts are abnormal growths on the skin that are caused by the human papillomaviruses (HPV). HPV viruses are a group of viruses that tend to infect the skin and mucous membranes such as the mouth and the inside of the vagina. HPV viruses can cause changes in the cells that they infect that causes them to grow abnormally, forming a wart. There are many different types of HPV viruses, and certain types of HPV viruses tend to cause different types of warts. Causes and risk factors for developing warts include the following.
Direct skin contact with a person who is infected with the HPV virus
The most common way to get a wart is to have direct skin contact with a person who is infected with the HPV virus. The virus is more easily spread through direct contact with a wart or with skin that is cut or injured but can also spread by seemingly normal-appearing skin through small defects in the skin.
Sexual contact with a person who is infected with the HPV virus
Sexual contact with a person who is infected with the HPV virus can lead to the development of a type of wart called anogenital warts, or condylomata acuminata. Similar to other forms of skin contact, transmission is more likely if the infected person has anogenital warts, but the virus can be spread even without active warts.
Touching a part of your own skin that is infected with the HPV virus and then touching an unaffected part of your skin ("autoinoculation")
One way for a person who is already infected with the HPV virus to develop new warts is to touch a part of their own skin that is infected with the HPV virus and then touch an unaffected part of their skin. This process is also know as autoinoculation. This is a common way by which children can spread warts to new parts of their bodies, since they may not always be careful about not touching infected sites.
Born vaginally to a mother who is infected with the HPV virus
Newborns can develop warts if they are born vaginally to a mother who is infected with the HPV virus in her genital tract. The virus can be transmitted through direct contact with the infected skin cells during delivery. In addition, it may be possible for the virus to be transmitted to the baby while still in the womb.
Handling meat, poultry, or fish
The risk of getting warts is higher among people in professions that involve handling meat, poultry, or fish. This tends to cause a certain type of wart called "butcher's warts."
Having a skin disorder or a weakened immune system
Having a skin disorder or a weakened immune system can predispose someone to getting multiple warts or warts that are resistant to treatment. One common skin condition associated with the development of warts is atopic dermatitis (eczema). Examples of diseases that cause weakened immune systems include HIV/AIDS and diabetes.
Treatment options and prevention for warts
Most warts in people with normal immune systems will go away on their own in one to two years. Therefore, some people may choose to observe their warts rather than treat them. Treatment options for warts include the following.
Some people with warts may opt to observe their warts without treatment. Most warts in people with normal immune systems will go away on their own in one to two years.
A number of topical medications can be used to treat warts . One common medication used is salicylic acid, which increases the turnover of skin cells and may stimulate the immune system to attack the wart. Other medications that may be used include squaric acid dibutylester (SADBE), dinitrochlorobenzene (DNCB), diphenylcyclopropenone (DPCP), bleomycin (Blenoxane), 5-fluorouracil (Efudex), cantharidin (Cantharone), imiquimod (Aldara), or trichloroacetic acid (Tri-Chlor).
Cryotherapy with liquid nitrogen
Another common method used to treat warts is by applying cold liquid nitrogen to the wart, in a procedure known as cryotherapy. In this procedure, a cotton swab is dipped into liquid nitrogen and applied to the skin, or liquid nitrogen is sprayed directly onto the wart for a short period of time to temporarily freeze the skin around the wart. This may be repeated every two to three weeks until the wart disappears.
Medication injected into the wart
In some cases, medication can be injected into the wart to treat it. Examples of medications that can be injected include Candida antigen and mumps antigen. These are components of other infectious organisms that cannot cause infection but will stimulate the immune system to attack the HPV virus.
In some cases, surgery can be used to remove the wart. This will immediately remove the wart but may result in scarring.
When to seek further consultation for warts
If you develop symptoms of a wart such as one or more painless bumps on your skin, you should go to your physician. Your physician can examine it to determine if it is a wart and then offer the appropriate treatment.
Dr. Liu received his medical degree from the University of Pennsylvania Perelman School of Medicine and is pursuing a career in ophthalmology. He graduated Phi Beta Kappa from Swarthmore College with a BA in biology. He has published research in multiple ophthalmology and healthcare journals and has received awards from Research to Prevent Blindness. In his free time, he enjoys running, biking, and spending time with his friends and family.
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