What Is a Wart?

A wart, also known as a verruca, is a small fleshy bump on the skin or mucous membrane caused by a virus known as human papillomavirus (HPV). There are over 350 types of HPV that can cause different types of warts on different parts of the body, most especially the hands, feet, and genitals.

Warts can be unsightly and grow to a significant size or in clusters. While warts are typically painless, pain can sometimes occur when pressure is placed on them (such as with plantar warts on the underside of a foot).

Warts can be extremely difficult to treat and will often recur (return). Even so, there are several options a person can turn to if a home remedy or over-the-counter treatment fails.

This article looks at the various types of warts a person can get, including their appearance and location. It also explains how warts are commonly diagnosed and treated.

General Characteristics of Warts

Warts are small raised bumps on the surface of the skin. Most are flesh-colored, although some come in various shades of white, pink, yellow, or brown.

Some warts contain tiny black dots. These are blood vessels that have grown rapidly and irregularly into a wart and have thrombosed (clotted). This is most often seen when a wart is cut away or reduced by abrasion.

Warts normally emerge from the top layer of skin in cylindrical columns. On thick skin, the columns can fuse and become packed tightly, creating a mosaic-like pattern on the surface.

Types of Wart

There are many types of warts with different shapes, sizes, and appearances. They vary not only by their location but also by the type of HPV that caused them.

Common Warts (Verrucae Vulgaris)

Per their name, common warts (verrucae vulgaris) are the most frequent type affecting three out of every four people sometime in their lives. They are recognized by their raised, rough, pebble-textured surface.

Common warts can occur anywhere on the body but are most often seen:

• On the fingers
• Near the nails
• On the backs of the hands

Those that occur around the fingernails and toenails are referred to as periungual warts, while those that develop under the nails are called subungual warts.

Plantar Warts (Verrucae Plantaris)

Plantar warts (verrucae plantaris) grow on the weight-bearing surfaces of the bottoms of the feet. They are rough in texture and often resemble calluses. Due to their location, plantar warts can be painful to walk or stand on.

Multiple plantar warts can grow together into a cluster called mosaic warts. These are especially hard to treat as much of the wart will grow beneath the surface of the skin.

Flat Warts (Verrucae Plana)

Flat warts (verrucae plana) are tiny growths of the skin that are smooth and flat or slightly rounded. They are sometimes called plane warts.

Flat warts appear in clusters of a few dozen to a hundred. Their location tends to vary by age and a person's biological sex, such as:

• On the legs of adult females
• In the beard area of adult males
• On the face of children

Filiform Warts (Verrucae Filiformis)

Filiform warts (verrucae filiformis) are an unusual-looking type of wart, forming long, thread-like or spiky columns that protrude from the skin.

Filiform warts most often appear on the face, especially:

• Around the eyes
• On or around the nose
• Around the mouth

Genital Warts (Condyloma Acuminata)

Genital warts (condyloma acuminata) can appear on or around your genitals or anus. They can be raised or flat and vary in size. When they form in groups, they may resemble cauliflower.

Genital warts are usually painless, but, in some people, they cause itching, burning pain, and bleeding.

While genital warts are technically verrucas, the preferred term for any wart on the genitals or anus is condyloma.

Age Warts (Verrucae Seborrhoica)

Age warts (verruca seborrhoica) are rough, raised, and light to dark brown in color. They initially start as yellowish skin discoloration and will develop over time into raised warts.

Age warts often appear from the age of 40 and increase in size and number with age. The condition is generally more common in people with fair skin than with dark skin.

Age warts mainly occur in the following locations:

• On the upper back
• On the forehead
• On the backs of the hands

Complications of Warts

Warts don't generally cause complications, but a few problems are possible. Among them:

• If you pick at or cut a wart, it can become infected.
• In people with compromised immune systems, warts can be especially difficult to treat.
• While genital warts are not commonly linked to cancer, such as cervical and anal cancer, they are sexually transmitted—as are other types of HPV that do cause cancer. To prevent the spread of sexually transmitted HPV, use condoms and reduce your number of sex partners.

Causes and Risk Factors of Warts

HPV is a group of over 350 viruses that can cause different types of warts and skin lesions. Many HPV infections cause no symptoms and over 90% will clear spontaneously within two years with no long-lasting consequence. Of these, over 40 types are sexually transmitted.

Warts are contagious and can spread by skin-to-skin contact, particularly if there are small tears or abrasions on the skin. It is also possible, but less likely, to get HPV by contact with contaminated objects or surfaces, such as a shared razor or locker room floor.

You may be more likely to get warts if you:

• Are a child or teenager
• Bite your nails or pick at the skin around them
• Are immune-compromised, such as people with HIV or those undergoing chemotherapy
• Have condomless sex with someone who has genital warts
• Have multiple sex partners

How Warts Are Diagnosed

Warts are easy to diagnose. Most people can recognize a wart on their own body, particularly if they have had one before. If you're not sure what it is, your healthcare provider can likely diagnose it just by looking.

Warts on the face or genitals—or those that are changing in color or shape or are bleeding—should be seen by a healthcare provider.

If your provider suspects skin cancer or a precancerous growth, they may order a skin biopsy. This is where a small piece of tissue is removed and examined under a microscope. This isn't necessary for most warts.

How Warts Are Treated

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. Those that don't clear up with home treatment may require prescription drugs or in-office therapies.

Home Remedies

A popular home remedy for wart removal is the duct tape method. For this procedure, you would put a piece of duct tape on the wart and leave it for six days. You would then remove the tape, soak the wart in water, and pare it down with an emery board.

If that doesn't get rid of it, you can wait 24 hours and try again. This may need to be repeated several times depending on the size and location of the wart.

Over-the-Counter (OTC) Wart Medications

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

Salicylic acid is applied to a wart and allowed to dry. Some practitioners recommend paring back the wart with a pumice stone or emery board before application. Soaking the wart in water before applying the acid and covering the area with a bandage will also aid with the absorption.

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

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

Another OTC option is an at-home freeze kit, also known as home cryotherapy. These products use liquid nitrogen delivered under pressure to freeze and destroy wart tissues. You simply point the precision applicator at the wart and spray.

Options include:

• Skin Clinic Freeze & Clear
• Dr. Scholl Freeze Away
• Compound W Nitro Freeze

Prescription Wart Medications

When OTC remedies aren't effective, there are topical medications available by prescription that can be applied to warts at home:

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

These products are applied once daily or several times a week per your healthcare provider's instructions. Depending on its severity, a wart should clear within nine to 12 weeks.

Surgeries and Specialist-Driven Procedures

Larger warts or those that resist treatment may require in-office care by a dermatologist. Some of the treatments are applied topically or injected into a wart to break down tissues. Others directly ablate (remove) tissues with either cold or heat.

Once the tissues have been broken down or reduced, the remaining tissues can be debrided (scraped) or excised (cut out).

Generally speaking, topical therapies and direct ablation methods are pursued before injections. Many injectable wart therapies are still regarded as experimental.

Specialist treatment options include:

• Topical therapies: These include chemical irritants like bleomycin, cantharidin, glutaraldehyde, formalin, and podophyllin or acids like lactic acid and trichloroacetic acid (TCA). Several applications may be needed.
• Cryotherapy: This involves the application of liquid nitrogen, usually with a swab, to freeze and kill a wart. After the wart crusts over and falls away, the underlying skin will usually heal with minimal scarring.
• Electrodesiccation and curettage: This is a procedure in which a wart is burned with an electrical needle or probe. Afterward, the dead tissue is scraped away with a spoon-shaped tool called a curette.
• Intralesional vitamin D injections: Injections with vitamin D3 have been used with varying degrees of success. One study involving 64 people with treatment-resistant warts reported that 90% experienced complete clearance after four treatments.
• Intralesional immunotherapy: This is a newer approach in which an injection of the MMR (mumps, measles, rubella) vaccine or Candida antigen stimulates the immune system to clear the wart. It usually involves five once-monthly injections.

Summary

Warts (verrucas) are small raised growths on the skin or mucus membranes caused by a group of viruses known as human papillomavirus (HPV). They are many different types of warts that can appear on different parts of the body, including the hands, feet, face, genitals, or anus.

HPV is contagious. It can be spread by skin-to-skin contact and even by touching objects or surfaces contaminated with HPV. Of the over 350 types of HPV that can cause warts or lesions, over 40 are sexually transmitted.

Warts can be diagnosed visually. Treatment options include OTC or prescription medications applied to the skin or specialist in-office procedures like cryotherapy or electrodesiccation.

A Word From Verywell

Warts can be unsightly, annoying, and difficult to treat. If you have a wart that simply won't go away, do not hesitate to contact a dermatologist who can offer recommendations on the best and safest ways to remove the type of wart you have.

A dermatologist is a physician specially trained in diseases and disorders of the skin, hair, and nails and should not be confused with a cosmetologist or esthetician who is a non-medical professional licensed to provide cosmetic treatments to the skin, hair, or nails.