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What are effective treatments for warts?
Q: My 6-year-old daughter has a wart on her knee. I just noticed it, but I don’t know how long she’s had it. What causes warts? (Is there anything related to what they say about touching frogs?) Can it spread?How can we get rid of it?
Eileen Boston
A: Warts are very common in childhood and generally considered harmless. Contrary to the myth, they’re not spread by touching frogs. Warts are caused by a virus, called human papilloma virus. The different strains of the virus cause different types of warts.

The wart virus is all around us: on people’s skin, nail clippers and towels that have touched people’s warts, and floors they’ve walked barefoot on. Children pick up the wart virus by touching someone’s wart or a surface that has touched the wart. However, the common wart virus is not highly contagious, and only some people catch them. Children are more likely to get warts where the virus can get into a break in the skin, e.g., around the fingernails of a nail-biter or on a scraped elbow or knee. People with immune problems are also more likely to get warts. If a child scratches her own warts, she can spread them to other parts of her body.

Once the virus is in the skin, it can cause a single wart or multiple warts, hard bumps on the skin that may be white, pink or brown-coloured. They are usually painless, but they can be itchy. Warts on the soles of the feet, called “plantar warts,” are usually flat and may be painful to walk on.

Health experts have different opinions on whether you should get warts removed. About 50 percent of warts go away on their own within two years, so some doctors advise just to wait and see. On the other hand, some advise treating a wart early because it is easier to remove when it is smaller, and it may continue to grow and spread. Also, some children feel self-conscious about their warts. Treatment options include:

Home treatment: Use only for older children (not infants or toddlers), and not for warts on the face or genitals, where the skin is more sensitive.
  • Over-the-counter wart removal preparations: At your local pharmacy, you can buy a variety of wart removal preparations (liquid, gel or patches) that contain salicylic acid, a mild acid that burns off the wart. File away the dead skin over the wart with an emery board or pumice stone, then soak the wart in warm water for 10 to 15 minutes. Dry the skin, apply petroleum jelly to the skin around the wart to protect it, then apply the treatment to the wart. Be careful to keep the site covered so the acid doesn’t get into your child’s eyes. Doing this daily for up to three months removes approximately 75 percent of warts.


  • Duct tape: This has been found to remove warts. You can use duct tape alone or with the salicylic acid treatment. Cover the wart with a piece of duct tape for six days. Remove the tape, soak, file the wart down and leave it uncovered overnight. Then repeat the process for up to two months.
Treatment at the doctor’s office:
  • Freezing: The doctor may swab or spray liquid nitrogen on the wart to freeze it off. First there is a burning sensation, followed by redness and blistering. Often three to four treatments are needed over the course of a few months.


  • Burning or cutting: Less commonly, the doctor may use an electrical instrument to burn the wart off, or a scalpel to cut it off. These are more likely to cause scarring.
Be sure to call the doctor before trying to remove a wart on a young child, if your child has warts on her face or genitals, or if the wart looks infected. Also see the doctor if the over-the-counter treatment hasn’t worked, or if you have any questions or concerns.

To try to prevent the spread of the wart virus, remind your daughter not to touch or scratch her wart. Consider having separate towels for family members. And get your daughter rubber flip-flops to wear in the shower at home and at the pool or gym.