Warts are small and very contagious skin growths that appear on the hands, fingers, knees, toes or feet. Find out how to treat this sometimes painful skin problem.

What are warts?

Warts are skin growths caused by the human papilloma virus (HPV). A single wart or groups of warts can develop anywhere on damaged skin where a cut or crack provides an entry point for the virus. The several types of warts include common warts and plantar warts.

Common warts

Common warts are, of course, the most common type. These warts look like small bumps that are rough on top. They often grow on the hands and fingers and are generally the same colour as the skin. 

Plantar warts

Plantar warts usually grow under the feet, often on pressure points or the heel or sole of the foot. They are often flattened, have small black spots and are covered with a tough top layer. As they get bigger, plantar warts may become painful because of body weight pressure. Plantar warts should not be confused with calluses or corns, which also develop on the soles of the feet or the toes. Unlike corns, a wart is painful when squeezed, and the skin lines aren't visible on the wart site. Don’t hesitate to ask your pharmacist if you're not sure what you have.

Who can get a wart?

Anyone can get a wart! An estimated one out of ten people has a wart. You can also carry the virus or catch it through contact with a person or a contaminated surface. The virus survives for a few days on hard surfaces and grows in humid conditions. This means that swimming pools and locker rooms are places where it’s easy to contract a wart. 

You can get warts more than once in your life, as treating a wart doesn't make the virus go away. Instead, the goal is to get rid of the wart to prevent the virus from spreading to other people or other parts of the body.

Children and adolescents get warts most often. People with depressed immune systems are also more at risk of getting warts.

How to prevent warts

Here are a few tips to avoid getting or spreading warts:

  • Don’t walk barefoot in public places. Wear flip flops in locker rooms, particularly in the shower and around the swimming pool. 
  • Protect small skin cuts with an adhesive bandage to prevent the virus from entering the cut.
  • Wash your hands after touching a wart.
  • Always keep the wart site dry to prevent other warts from developing.
  • Put a bandage on the wart to keep it from spreading to other sites or other people.
  • Avoid sharing your towels, shoes or clothes if you have warts.

Wart treatment

Most warts disappear on their own without treatment within 6 to 24 months. However, it's better to treat a wart if it causes pain. Treating it will also keep it from spreading to other parts of the body or to other people. You can treat the wart yourself with a number of over-the-counter (OTC) products at the pharmacy. 

OTC medication 

The products recommended most often to treat warts contain salicylic acid concentrations of between 11% and 40%. Salicylic acid may be the only ingredient or it may be combined with lactic acid, which makes the treatment more effective but also causes more irritation. Salicylic acid at low concentrations (11% to 20%) is used for common warts, while higher concentrations (17% to 40%) are used for plantar warts. These medications come in different forms: creams, gels, collodions (liquid bandages), discs and adhesive bandages. All of these products are effective when applied correctly.

Watch out! Salicylic acid is contraindicated for people with diabetes and people with circulation problems. Talk to your doctor if this is your situation. People with an aspirin allergy should also avoid these products.

Five steps to treat warts with salicylic acid

To treat warts with salicylic acid, repeat steps one to five below until the wart disappears, up to a maximum of 12 weeks. If the wart hasn’t gone away at that point, you’ll need to consult a doctor. 

  1. To keep the wart from spreading, wash your hands before and after treating the wart, and use a dedicated towel to clean and dry the areas with warts.
  2. Before applying a product on a wart, wash it with soap and water and soak it in warm water for 5 to 15 minutes to soften it.
  3. Gently file the wart with a pumice stone or emery board so that the product can penetrate into the wart. Avoid filing so hard that the wart bleeds. Don’t try to cut the wart. The blood from a wart is contaminated and can spread the virus to other parts of the body or to another person.
  4. Protect the healthy skin by applying petroleum jelly (VaselineTM) or transparent nail polish around the wart.
  5. Apply the product just to the wart. When using a bandage or a disc, cut it down so that it covers just the wart. After applying the product, put an adhesive bandage on the wart.

To be effective, the product needs to be used daily or as recommended by the manufacturer. If your skin becomes damaged or bleeds a bit after you apply the product, stop the treatment until the damaged skin heals. 

Other OTC products are available on the market but are not used as much. These products include cantharidin, which needs to be applied by a doctor as it can be toxic.

Always ask your pharmacist about the best treatment for your situation and follow the manufacturer’s recommendations.

OTC cryotherapy

Cryotherapy, or “therapy with cold,” treats the wart with an extremely cold substance. OTC products contain dimethylether and propane. After the product freezes the wart, a blister appears underneath to leave room for healthy skin to regenerate. If the first application doesn't work, repeat every 10 to 14 days for a maximum of three total applications. If the treatment fails after three applications, consult a doctor. This treatment can cause more side effects than salicylic acid and may be less effective than the cryotherapy done at the doctor’s office. OTC cryotherapy is contraindicated for children under the age of four, people with diabetes, people with poor circulation, and pregnant women or women who are breastfeeding.

If the treatment doesn’t work, you can consider other approaches with your doctor, such as cryotherapy, or the liquid nitrogen treatment applied at the doctor’s office.

Did you say “duct tape”?

A research study has indeed demonstrated the effectiveness of duct tape to eliminate warts, although it’s not fully clear how it works. You generally apply the duct tape for no more than two months. Curious to know more about the duct tape method? Ask your pharmacist!

When to consult a doctor

Before treating a wart, you must consult a doctor in the following cases:

  • You’re unsure if what you have is a wart.
  • You have warts on your face, under your fingernails or toenails, or on your genitals or anus.
  • You have multiple warts in one or multiple areas.
  • The wart grows during treatment or starts to become painful.
  • The wart bleeds or the wart site is infected.
  • You have diabetes or blood circulation problems.
  • You have an immune system deficiency (i.e., you have HIV or are taking an immunosuppressive drug).

You must also consult a doctor if you haven’t seen any improvement after 2 weeks of treatment or if the wart is still there after 12 weeks of treatment.

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