Warts are caused by viruses in the human papillomavirus (HPV) family.
The appearance of a wart depends on its location on the body and the thickness of the skin.
Palmar warts appear on the hand. Plantar warts affect the feet.
Fast facts on warts
Here are some key points about warts. More detail is in the main article.
- A wart is a small growth on the skin that may look like a solid blister or a small cauliflower.
- Types of wart include common warts, flat warts, pigmented warts, and plantar warts.
- Black dots in the wart are blood vessels that can lead to bleeding.
- Most warts disappear in 1 to 5 years without medical treatment, but treatment is available for warts that are large, numerous, or in sensitive areas.
- Treatments include salicylic acid, duct tape, cryotherapy, surgery, laser treatment, electrocautery, photodynamic therapy, chemical treatments, topical creams, cantharidin, and antigen shots.
- Warts or verrucae should be covered up with a waterproof Band-Aid when swimming.
Types of wartThe following are the
most common types of wart.
Common warts, or verruca vulgaris
Plantar warts appear on the base of the foot.
Common warts have a firm, raised, rough surface and may appear cauliflower-like. They can occur anywhere, but they are most common on the knuckles, fingers, elbows, knees, and any area with broken skin.
Clotted blood vessels are often visible in common warts as small, darkened spots. These are known as seed warts.
Painful verrucae appear on the soles of the feet, heels, and toes.
They usually grow into the skin because the person's weight pushes onto the sole of the foot. They normally have a small central black dot surrounded by hard, white tissue. Plantar warts are often difficult to clear.
Plane warts, or verruca plana
Plane warts are round, flat, and smooth. They can be yellowish, brownish, or skin colored.
Also known as flat warts, they grow most often on sun-exposed areas.
They tend to grow in larger numbers, possibly between 20 and 100. However, of all wart types, they are most likely to disappear without treatment.
Filiform warts, or verruca filiformis
Filiform warts are long and thin in shape. They can grow rapidly on the eyelids, neck, and armpits.
Mosaic warts are multiple plantar warts in a large cluster.
Unlike moles, warts are often the same color as the person's skin. Warts do not contain pus unless they become infected.
If infection occurs, they may require treatment with antibiotics.
When should I see a doctor?
It is a good idea to see a doctor if the wart:
- causes pain
- bleeds easily
- changes appearance
- spreads easily to other parts of the body
- comes back after prior removal
- appears in an area that leads to constant bumping and bleeding so as to affect daily activities, such as shaving, sports, and so on
Individuals who want the wart removed for cosmetic reasons should see a doctor.
Insurance is unlikely to fund cosmetic treatment, but primary care physicians, dermatologists, and podiatrists can all treat warts.
Causes and risk factors
Verrucas and plantar warts can be treated by creams containing salycylic acid.
HPV viruses cause the excessive and rapid growth of keratin, which is a hard protein on the top layer of the skin.
Different HPV strains cause different warts. The wart-causing virus can be passed on by close skin-to-skin contact, and through contact with towels or shoes.
The virus can spread to other parts of the body through:
- scratching or biting a wart
- sucking fingers
- biting fingernails, if there are warts around the nails
- shaving the face or legs
Having wet or damaged skin, and coming into contact with rough surfaces increase the risk of infection.
For example, a person with scratches or cuts on the soles of their feet is more likely to develop a verruca in and around public swimming pools.
Wearing shower shoes or flip flops while using public showers or walking near public swimming pools can help prevent this.
The risk of catching warts from another person is low, but they can be passed on, especially if the person has a compromised immune system. This includes people with HIV or AIDS, and those using immunosuppressants following a transplant.
Genital warts are more contagious.
Handling meat as an occupation will also increase the risk of contracting warts. A study carried out by the American Academy of Family Physicians showed that 33 percent of slaughterhouse workers and 34 percent of retail butchers have warts on the hand.
Most warts are harmless, but some strains of HPV can cause warts on, in, or around the genitals.
These warts can be more serious. In women, they can potentially lead to cervical, anal, and vulvovaginal cancer.
Anyone who develops genital warts should see their doctor for assessment.
Diagnosis and treatment
Palmer warts occur on the hand and are frequent in those who handle meat for a living.
Warts and verrucae are easy to identify.
A doctor may ask whether any other family members have warts.
Occasionally, they may take some tissue from a wart to examine it under a microscope to confirm it is wart, especially if the wart does not respond to typical therapies.
Most warts clear up without treatment.
The time taken varies between individuals. It can range from a few weeks to several years, depending on the location and number of warts. They tend to disappear faster among young children.
All wart treatments are designed to irritate the skin and get the body's own infection-fighting cells to clear the warts.
Most over-the-counter creams, gels, paints, and medicated Band-Aids contain salicylic acid.
It is important to protect the skin around the wart before applying this treatment because salicylic acid may destroy healthy skin. Do not apply to the face.
Applying petroleum jelly or a corn plaster to the skin around the wart can protect it from damage.
Some tips can enhance the effectiveness of this treatment.
- Soften the wart by rubbing dead tissue from the surface of the wart weekly using a pumice stone or emery board. Make sure that the pumice stone or emery board is not used on any other part of the body or by another person.
- Before applying the medication, soak the wart in water for about 5 minutes.
Treatment is normally applied daily for about 3 months. If the skin becomes sore, treatment should be stopped.
Some people use duct tape to get rid of warts. This is not for use on the face.
Duct tape is placed over the wart and left there for about 6 days.
The wart is then soaked in warm water for about 5 minutes, after which the dead tissue is gently rubbed off using an emery board or pumice stone. Do not share pumice stones used on warts.
Leave the wart uncovered overnight, and apply a new piece of duct tape the next day.
Freezing liquid, often nitrogen, is sprayed onto the wart, destroying the cells. A blister develops, which eventually scabs and falls off a week or so later.
This treatment must be carried out by a healthcare professional. If the wart is large, this may require a local anesthetic and several sessions.
Pharmacies sell dimethyl-ether or propane spray for self-administration. These should not be used on the face, and they are less effective than cryotherapy that is carried out by a qualified professional.
A dermatologist can use cryotherapy to remove warts.
This not common for warts, and there is a risk of scarring. Warts that resolve by themselves do not scar.
Sometimes a doctor may recommend surgery if other treatments have not worked.
Most warts can be shaved off with a surgical razor under local anesthesia.
Doctors may recommend applying a topical cream to the site even after the wart's removal, to improve the chances of it clearing.
Laser treatment uses a precise laser beam to destroy the wart.
A doctor may apply a substance containing an extract from an insect called a blister beetle and other chemicals to the warts. The area is then covered with a bandage.
This is painless, but it creates a blister that may be uncomfortable. The blister lifts the wart from the skin, and the doctor removes the dead part of the wart.
Candida antigen shots
The human immune system does not notice a wart, but if the system is stimulated locally, some activated immune cells in the area will recognize it and take action. This procedure leaves no scarring.
This treatment may not be suitable during pregnancy.
If warts do not respond to standard treatments, a dermatologist, or skin specialist, may offer other options.
- Immunotherapy attempts to make the patient's immune system destroy the warts
- Bleomycin, or Blenoxane, can be injected into the wart to kill the virus. Bleomycin is also used for treating some types of cancer.
- Retinoids, derived from vitamin A, disrupt the wart's skin cell growth.
- Antibiotics are only effective in the case of infection.
Common warts, especially around the fingernails and toenails, may be difficult to eliminate completely or permanently.
Many people who are susceptible to warts will regularly have them, even after successful treatment.
To reduce the risk of catching or spreading warts:
- Do not touch other people's warts.
- Do not use other people's towels, washcloths, or other personal items.
- Do not share shoes and socks with other people.
- Do not scratch warts or verrucae, as this can cause them to spread.
- Wear sandals when entering and exiting communal showers and pools.
- Cover warts or verrucae with a waterproof covering when swimming, and socks or gloves elsewhere, for example at the gym.
- Do not brush, comb, shave, or clip hair in areas that have warts.
- When filing or cutting nails do not use the same utensil on the infected nail and the healthy nails.
- Do not bite fingernails if warts are near them.
- Keep hands as dry as possible.
- Wash hands thoroughly after touching a wart.
Warts are common, and they can cause embarrassment, but treatment can often help eliminate them.