An Overview of Warts

illustration of a wart
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In This Article

A wart, or a verruca, is a fleshy growth on the skin caused by the 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.

Symptoms

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.

Contrary to popular belief, warts do not have "roots." They originate from the top layer of skin, the epidermis. As they grow down into the second layer of skin, the dermis, they can displace the dermis but not form roots: The underside of a wart is smooth.

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.

Causes

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

The human papillomavirus is very common. Most people are exposed to it at some point in their lives and yet will never develop a wart.

Diagnosis

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 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.

Treatment

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

Many warts can be treated with simple over-the-counter (OTC) remedies, but for warts that are resistant to these therapies, there are other effective treatment procedures that can be done at the doctor's office.

Salicylic Acid

Salicylic acid is a very common and effective over-the-counter treatment. It can be found in several forms, including a thick oil or incorporated into an adhesive plaster form.

Some examples of salicylic acid wart removers include:

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

You can ask your pharmacist for help choosing an OTC wart removing a product.

The best way to use salicylic acid is to first pare the wart with a blade, pumice stone, emery board, or small scrub brush. Soaking the wart in warm water will aid in the absorption of the medicine.

Salicylic acid is applied to the wart and allowed to dry. The normal surrounding skin may be protected with petroleum jelly, and you may wish to outline the wart with this prior to treatment to avoid treating normal skin surrounding the wart.

Occluding the treated wart with a band-aid or piece of tape also improves the absorption of the medicine, and can decrease the chance the medicine will get on normal skin. Make sure to wash your hands after application and avoid contact of the treated area (for example, if on your fingers) with your eyes.

Salicylic acid requires a consistent application. Applications should be repeated daily, ideally around shower or bath time.

Duct Tape

An increasingly-used home remedy for warts is duct tape. To do this, duct tape (any color) is applied to the wart and kept in place for six days. After this period of time, you should soak the wart and pare it down with an emery board or file to remove the top layer.

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

Studies have shown mixed results with duct tape, but it is a home remedy with few side effects.

Prescription Medications

In cases where over-the-counter products aren't effective, there are other treatment options available by prescription. These medicines may be applied to warts or injected into them. They include:

  • Lactic acid
  • Trichloroacetic acid (TCA)
  • Formalin
  • Glutaraldehyde
  • Cantharidin
  • Podophyllin
  • Retin-A (tretinoin)
  • Bleomycin

These treatments should be supervised by a health care provider.

Cryotherapy (Freezing)

Cryotherapy (freezing) is another effective treatment for warts. A healthcare provider applies liquid nitrogen — as a spray or on a cotton swab — to the wart. This freezes and kills the affected cells.

The connective tissue is not destroyed; therefore, the lesion usually heals without significant scarring.

The human papillomavirus is not killed by cryotherapy and is released into the surrounding tissue allowing the immune system to kill it.

A blister typically forms on the site treated, crusts over, and falls off. Since blisters are painful to walk on, cryotherapy is not the first choice for warts on the bottom of the foot (plantar warts).

Options for Resistant Warts

Some warts do not seem to respond to repeated treatments with topical medicines, cryotherapy, or even duct tape. In this case, your doctor may recommend cautery (heat therapy) or surgically removing the wart. The area beneath the wart is usually numbed with lidocaine before surgery is done.

The combination of Aldara (imiquimod 5%) plus duct tape may also be helpful with recalcitrant warts.

Finally, further treatments such as pulsed dye laser, photodynamic treatment, or injecting Candida antigen, other antigens, dinitrochlorobenzene, or vitamin D directly into the wart have all been tried.

In one study with resistant warts, vitamin D had an almost 90% complete success rate for recalcitrant warts.

A Word From Verywell

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.

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Article Sources

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