Don't blame the toads

Contrary to folklore, warts are not caused by toads. Strains of the human papillomavirus (HPV) are responsible for at least 50 of the different benign skin growths that we call warts.

Around 90% of all adults have had at least one wart infection making warts extremely common. Warts can develop at any age but are most common in children. While generally harmless, warts are contagious, passing from one area of a body to another or from person to person by direct contact with the infected skin. Warts are treatable using a variety of therapies.

Detailed Description

Warts are the result of an infection by one of the human papillomaviruses (HPV). Common warts are characterized by a thickening of the layers of skin forming a firm growth with a rough surface. They can be lighter or darker than the surrounding skin as well as having small black spots. Warts begin very small and grow larger, as big as 1/4 inch across, with the ultimate size and shape determined by their location on the body and the particular strain of papillomavirus at work. They can be spread by another person or in the same person from another part of the body.

The two most common forms of warts are common warts (verruca vulgaris) and flat warts (verruca plana). The common wart appears alone as a bump or smooth spot, or in clusters. They have rough, skin-colored bumps 5 to 10 mm in diameter, and often develop on fingers, hands, toes, and knees. Flat warts are slightly raised and (not surprisingly) flat-topped, and often appear on the face, neck, forearms, wrists, and legs. They usually appear in groups as smooth, yellow-brown spots.

Venereal (anogenital) warts (condylomata acuminata) are moist growths located mainly near the urethra and anus in both genders, on the labia in women, and on the head of the penis and on the foreskin in men.

Plantar warts are found on the soles of the feet. The pressure from walking causes them to flatten and grow inward. They are usually surrounded by thickened skin, and can be extremely tender.

In healthy people (without compromised immunity), over half of warts will disappear without treatment in two years or less. However, the drawbacks of warts include poor appearance on certain body locations, irritation, the possibility of infecting others, and pain caused by some, especially with trauma.

Other types of warts include:

  • Filiform warts are long, narrow, small growths on the face, neck, or eyelids.
  • Periungual warts appear around the fingernails. They can be dry and cracked, resembling hangnails.
  • Pedunculated warts on the fingers and neck look like tiny cauliflowers.
  • Laryngeal papillomas on the larynx in infants following vaginal birth or in adults due to oral sex

How Common Are Warts?

Warts affect 7% to 10% of the population in the United States. There are approximately one million new cases of venereal warts every year in the United States. Warts predominantly occur in children and young adults, but can infect all age groups. Venereal warts affect predominantly those between ages 15 and 30. Though the sex ratio varies for the different types of warts, females are generally more inclined to develop warts than males. Venereal warts (condylomata acuminata) affect both sexes equally.

What You Can Expect

Warts generally appear one to 12 months after contact with the virus, usually in two to three months. Over half of warts will disappear without treatment in two years or less. Others will come back, whether treated or not.

Genital (venereal) warts are sexually transmitted. Symptoms may appear from a few weeks to several months after infection. It is not clear to what extent treatment reduces the spread and recurrence of genital warts. For a number of reasons, including the association between venereal warts and cervical cancer in women, these warts are usually treated. With various treatments, clearing of the lesions occurs about 40% to 70% of the time, and the recurrence rate is 25% to 50%. Men should be treated particularly to prevent its spread to women. Women should be treated, and examined internally, because of the association with cervical cancer.

While most warts are not dangerous, it's advisable to get treatment promptly to prevent spreading, especially if they're located on high-contact areas, such as hands.

Conventional Treatment

Goals of Treatment

Since no treatment can guarantee that warts won't come back, the goal is to create "wart-free" intervals for as long as possible, by removing them. Topical preparations (films and paints), injectable compounds, freezing, chemical agents, and mechanical or surgical measures — including "cutting" with lasers — can all be used for wart removal. However, the cause of the growths — human papillomavirus (HPV) — can not be cured at this time.

Treatment Overview

There are many ways to remove warts, including liquid nitrogen, chemicals, electrodesiccation, laser therapy, and surgery. The use of a particular therapy depends on various factors, including the type of wart and its location.

All methods of wart removal depend on your immune response. It is this defense mechanism that causes warts to go away of their own accord or not return.

Persistent warts, especially around the mouth, nails, or genital region, likely warrant referral to a dermatologist. For venereal warts, it is especially important to prevent contagion and to caution your sexual partners. Women with venereal (anogenital) warts should have a Pap smear. If it shows an atypical result, a colposcopy should be performed. Warts near the anus or the opening of the urethra should have a proctoscopy or urethroscopy, respectively.

Drug Therapy

Drugs most commonly prescribed

For nonvenereal warts, agents include:

  • Various chemicals. These treatments begin by paring or trimming the wart, then soaking the area in warm water to moisten it.
  • Keratolytic agents: Salicylic and lactic-salicylic acids, often used for common or plantar warts, soften the infected skin so that it can be peeled off. The daily treatment can take weeks or months to eradicate a wart, with almost no side effects, although the surrounding healthy skin should be protected.

For venereal warts, medications applied by the physician include:

Interferon (Alferon N, Intron, Roferon-A)

On-Label Efficacy

buy Accutane

Off-Label Efficacy


Off-Label Efficacy


Off-Label Efficacy


Off-Label Efficacy


On-Label Efficacy

Trichloracetic acid

On-Label Efficacy

Podophyllin resin (should not be used during pregnancy)

On-Label Efficacy
Secondary choices

For nonvenereal warts, second choices include:

Bichloracetic acid

On-Label Efficacy


On-Label Efficacy

Non-Drug Therapies


The process of freezing the wart cells with liquid nitrogen to destroy them. This is an office procedure that doesn't require anesthesia. There's no bleeding and, if used properly, the process will minimize scarring. Freezing stings slightly during the application. A blister will develop at the treatment site. The roof of the blister will fall off within a few days. If clothing irritates the blister, cover it with a small adhesive bandage. More than one treatment may be needed.

Operative removal

Warts can be removed with a curette or scissors, or by shaving off the wart with a scalpel. Trichloroacetic acid or Monsel's solution is often applied to the resulting wound, or light electrocautery is used to complete the treatment.

Laser therapy

The CO2 laser has proven effective against periungual, plantar, and types of venereal warts.Surgery is often effective for growths, such as plantar warts, that are difficult to remove, or for recurring warts. Scarring can occur.


Electrodesiccation uses an electric needle to burn away warts. If electrosurgery is performed, make sure you keep the treatment site clean with soap and water. You can cover the site with an adhesive bandage.

Healthcare Professionals Who May Be Involved in Treatment

  • Internists
  • Pediatricians
  • Family medicine physicians
  • Dermatologists
  • Gynecologists
  • Urologists

Activity and Diet Restrictions

There are no activity restrictions for most warts. If plantar warts are on a weight-bearing surface, they may cause discomfort with activity. "Corn plasters" can be cut into a donut shape around the wart to minimize callus formation and reduce pain.

Monitoring the Condition

After treatment, you should call your doctor if:

  • An infection develops at the treatment site, indicated by redness, swelling, pus.
  • Your or your child's temperature rises above 101F.
  • The warts don't disappear or other warts appear.

Possible Complications

Warts can spread to other body parts. You could also experience secondary infections and scarring. Chronic pain can occur after plantar warts are removed.

Genital warts and laryngeal papillomas can become cancerous.

Quality of Life

Warts and their treatment should not impact your quality of life.

Considerations for Women

Girls and young women are more susceptible to warts than boys and young men.

Certain types of viruses responsible for warts — human papillomaviruses (HPV) — are associated with cancer of the cervix. Women with venereal (anogenital) warts should have Pap smears. If they give an atypical result, or show evidence of active wart infection, a colposcopy should be performed.


Venereal warts can be transmitted to newborns through an infected birth canal. Podophyllin resin and Podofilox should not be used to treat warts during pregnancy, but they should be treated by other means, such as boric acid suppositories, to prevent laryngeal papillomas in infants.

Considerations for Children and Adolescents

Since children are usually extremely active, it's recommended that you cover warts to help prevent contact and spreading, as well as treatment sites to prevent additional damage that can lead to complications.

Considerations for Older People

As people get older, their immune systems become less effective, opening the door for the development of warts, along with other infections, malignancies, immune disorders, and allergies.


Last updated 26 March 2012


  • Verrucas
  • Epidermodysplasia verruciformis
  • Condyloma
  • Acuminata plantar wart
  • Filiform warts
  • Flat warts
  • Laryngeal papillomas
  • Pedunculated warts
  • Periungual warts
  • Venereal warts


Established Causes

Different strains of the human papillomavirus are the cause of warts. They infect the skin's epithelial layer causing cells to multiply abnormally fast, resulting in skin growths.

Risk Factors

The risk factors for venereal warts can be separated from the risk factors of the remaining types of warts.

A general list of risk factors for nonvenereal warts includes:

  • AIDS and other immunosuppressive diseases
  • Use of immunosuppressive drugs
  • Skin trauma
  • Atopic dermatitis
  • Lymphomas
  • Locker-room use

Risk factors associated with venereal warts include:

  • Being a young adult
  • Sexually active
  • Not using condoms
  • Commencing sexual activity at a young age
  • Other venereal diseases
  • Pregnancy
  • Poor nutrition
  • Unsanitary living conditions
  • Caucasian
  • History of genital warts
  • Smoking

Symptoms & Diagnosis

Major types of warts include the common wart (verruca vulgaris), the flat wart (verruca plana), and the anogenital wart (condylomata accuminata). The symptoms vary depending on the type of wart you have.

In general, a wart is a raised part of the epithelial layer of the skin marked by clearly defined borders.

Warts can also:

  • Be smooth or rough in texture
  • Be of the same color of skin or be a different color
  • Be present in lines or clusters
  • Be painful
  • Cause itching
  • Can interrupt skin lines

Features specific to anogenital warts:

  • Penile lesions: often smooth and papular (often occurring in groups of three or four)
  • Occur in males on the glans, corona, frenulum, prepuce, meatus, shaft, and scrotum
  • Occur in females on the labia, clitoris, periurethral area, perineum, vagina, and cervix
  • Surface may be smooth or very rough
  • Multiple fingerlike projections
  • Irritation
  • Bleeding

Differential Diagnosis

Warts are usually straightforward to diagnose by their characteristic appearance. In the case of flat warts and plantar warts, it may be difficult to distinguish them from callused skin.

Venereal warts must be distinguished from other genital lesions including:

  • Lichen planus
  • Seborrheic keratoses
  • Molluscum contagiosum
  • Squamous cell carcinoma (in situ)

Other causes of genital sores with less similar appearance include:

  • Herpes
  • Syphilis
  • Chancroid
  • Lymphogranuloma venereum

How are Warts Diagnosed?

Usually observation of your own symptoms, along with a physical examination by your doctor and reference to your medical history, is sufficient to diagnose warts. Warts can be identified by examination under a magnifying lens; they display a highly organized mosaic pattern.

For venereal warts the diagnosis may include:

  • Biopsy with highly specialized identification techniques
  • Colposcopy
  • Anoscopy
  • Pap smear

Laboratory Work

For venereal warts, a serologic test for syphilis as well as screening for other sexually transmitted diseases may be conducted.

Specific Tests

Definitive diagnosis can be achieved with the following tests:

  • Electron microscopy
  • Immunohistochemical study
  • Nucleic acid study

Alternative care


  • Echinacea: helps fight viral infections by stimulating the release of interferon, the body's own virus-fighting chemical.


Imagine ... no more warts. Hypnotherapists claim good success using hypnosis and visualizations to help cure warts. Hypnotherapy and visualizations both involve deep relaxation, which may help stimulate the immune system to defeat the wart virus.

Self care & Prevention

Preventing Transmission of Warts

  • Wear thongs or splash shoes in public showers. If you're barefoot, you might pick up the virus that causes plantar warts.
  • Using an electric razor instead of a safety razor may prevent the spread of warts caused by shaving.
  • To avoid transmitting or catching the virus that causes genital warts, use condoms. They will usually prevent transmission -- if the condom completely covers the warts.

Self-Care Measures

  • Don't pick at your warts. This can spread the viral infection that causes them.
  • To eliminate finger and plantar warts, use an over-the-counter salicylic acid plaster. Follow package directions.
  • To make a homemade plaster, use aspirin, a form of salicylic acid. Crush two standard aspirin tablets and add just enough water to make a paste. Cover the wart with this paste, then cover with a bandage. Change the bandage and add new aspirin paste once a day until the wart is gone.