An Overview of Warts

A wart, or verruca, is a small, fleshy bump on the skin or mucous membrane caused by human papillomavirus (HPV). There are several types of warts that can appear anywhere on the body—in particular, the hands, feet, and genitals. With the exception of a type of wart the grows on the bottom of the feet, warts are painless. However, they're highly contagious and can easily spread from one area of the body to another or from one person to another through close contact, such as a handshake. Warts are easy to identify visually, and so no special tests are needed to diagnosis them. Warts typically are treated with topical medications or procedures to remove them. They're most common in children and young adults.

Warts are small, raised bumps on the surface of the skin. Most are flesh-colored, although some warts present in various shades of white, pink, yellow, or brown. Some contain tiny black dots — blood vessels that have grown rapidly and irregularly into the wart and thrombosed (clotted).

Warts normally grow out of the skin in cylindrical columns. On thick skin, the columns can fuse and become packed tightly together creating a mosaic-like pattern on the surface.

There are several types of warts:

• Common Warts (Verrucae Vulgaris): Common warts are raised with a rough, pebble-textured surface. They most often appear on the fingers, near the nails, and on the backs of the hands, but can occur anywhere, especially in areas where the skin has been broken.
• Plantar Warts (Verrucae Plantaris): Plantar warts appear on the weight-bearing portion of the bottoms of the feet. They're rough in texture and may resemble calluses. It can be uncomfortable to walk or stand on a plantar wart. Multiple plantar warts that grow together into a cluster are called mosaic warts and can be painful and hard to treat.
• Flat Warts (Verrucae Plana): The surface of these tiny growths, also called plane warts, is smooth and flat or rounded. They appear in clusters of a few dozen to a hundred. Women tend to get flat warts on their legs, men in the beard area, and children on the face.
• Filiform Warts (Verrucae Filiformis): These unusual-looking warts are long, thread-like or spiky columns that protrude from the skin. They most often appear on the face, especially around the eyes, nose, and mouth.
• Periungual Warts: Rough and irregularly-shaped, these warts develop around fingernails and toenails. They may extend beneath the nail, causing pain and disrupting normal nail growth.

The virus responsible for warts is the human papillomavirus (HPV). This common virus resides in the bottom layer of the epidermis (the top layer of the skin) and replicates in such a way as to appear similar to normal-looking skin.

Warts are extremely contagious. They spread through direct skin contact — by shaking hands with someone who has a wart on their hand or finger, for example — or by touching something that is harboring HPV, such as a towel that's been used by someone with a wart.

Warts also can be picked up by walking barefoot on a surface on which the virus has been shed by another person, such as the floor of a gym locker room. And they can be transmitted from one area of the body to another. They're especially likely to develop where there's an opening in the skin, such as a cut or a ragged hangnail.

Some people are more prone to getting warts than others, including:

• Children and teenagers
• People who bite their nails or pick at the skin around their nails
• People who have immune system-related diseases such as AIDS and lymphoma, or those who are receiving chemotherapy

Warts are easy to diagnose: Most people can identify a wart on their own body, but if they're unsure a doctor can easily confirm the presence of a wart with a visual inspection. It's only if there's a suspicion that a wart might be skin cancer or a precancerous growth that a biopsy, in which a small piece of the lesion is removed and inspected under a microscope, will be necessary.

For that reason, it's important to see a physician for any unidentifiable growth on your own body or on that of a child or someone else you care for. You also should see a doctor for warts that are large or growing rapidly, multiplying, or if they're itchy, bleeding, or painful. Warts that develop on the face or on the genital area should always be seen by a physician.

Most warts resolve within weeks or months without treatment, although some may take many years to fully clear. However, because warts can be uncomfortable or unsightly, most people opt to remove them.

Many warts can be treated with simple over-the-counter remedies but those that resist home treatment may require prescription drugs or in-office therapies.

A popular home remedy for wart removal is duct tape. For this procedure, duct tape (any color) is applied to the wart. After six days, the duct tape is removed and the wart is soaked in water and pared down with an emery board or file.

After 24 hours, duct tape can again be applied for another six days if any of the wart remains. This may need to be repeated several times depending on the size and location of the wart.

Salicylic acid is a common and effective over-the-counter wart removal treatment. It can be found in several forms, including oils, drops, and infused adhesive pads or strips.

Some of the more popular salicylic acid-based wart removers include:

• Compound W
• Dr. Scholl's Clear Away
• DuoFilm
• Wart-Off

Salicylic acid is applied to the wart and allowed to dry. Some practitioners recommend paring back the wart with a pumice stone or emery board before application.

In cases where OTC remedies aren't effective, there are other treatment options available by prescription. These topical medicines can be applied to warts at home and include:

• Retin-A (tretinoin), a topical cream that is particularly effective in treating flat warts
• Aldara (imiquimod), a topical cream used to treat non-melanoma skin cancers and anal or genital warts

The creams may be applied once daily or several times per week per your doctor's instructions. Depending on the severity of a wart, clearance or partial clearance may be seen within nine to 12 weeks.

Larger warts or those that resist treatment may require in-office care with a qualified dermatologist.

Some of the recommended treatments are applied topically or injected into a wart to break down the accumulated tissues. The tissue may then be debrided (scrape) or excised (cut out) by a doctor. Some of the more commonly used agents include:

• Lactic acid
• Trichloroacetic acid (TCA)
• Formalin
• Glutaraldehyde
• Cantharidin
• Podophyllin
• Bleomycin

Cryotherapy is another effective treatment in which liquid nitrogen is applied to a wart, usually with a swab, to freeze and kill the excess tissue. After the tissue crusts over and falls away, the underlying skin will usually heal with minimal scarring.

Electrodesiccation and curettage involve the burning of a wart with an electrical needle or probe, after which the dead tissue is scraped away with a spoon-shaped tool called a curette.

Intralesional vitamin D injections have also been used with varying degrees of success. One small study involving 64 people with treatment-resistant warts reported that 90% experienced complete clearance after four treatments.

Intralesional immunotherapy is a newer approach to wart removal in which an injection of the MMR (mumps, measles, rubella) vaccine or Candida antigen can stimulate the immune system to clear the wart. A response is generally seen after five months of one-monthly injections.

Warts are very common, especially in children and young adults. They are caused by direct contact with a virus. In time, most warts will go away on their own, yet they can be annoying and unsightly when left untreated.

Many options are available to get rid of warts, from over-the-counter topical preparations to freezing or burning in the clinic.