Wart Treatments

Warts are usually harmless and generally go away on their own after a few weeks or months. They can be bothersome and unattractive as well as painful. Various treatments can help warts go away faster.

Warts are caused by viruses known as human papillomaviruses (HPV), of which there are more than 100 different types. Warts are most common on your hands, feet, and face. They may also develop in the genital and anal areas. This information doesn't cover the treatment of genital warts.

Several different treatments can improve the chances of getting rid of warts faster, but they don't always work. Warts on the soles of the feet are tough to treat because they're sometimes pushed inward. No treatments have been proven to work here. Also, new warts may form after successful treatment if some viruses or infected skin cells remain.

Warts are often treated with a salicylic acid solution or cryotherapy. These are also the best-studied treatments.

How effective is salicylic acid in treating warts?

Salicylic acid solutions are applied to the skin several times per day over several weeks. The solution forms a thin layer over the wart. This layer is removed before the solution is used again. If possible, the top layer of the wart is also carefully removed. Most salicylic acid solutions are available without a prescription at the pharmacy. Some of these products also contain lactic acid.

An analysis of studies on the effectiveness of salicylic acid solutions has shown that they are effective. These are the results after three to six months:

• Without salicylic acid: About 25 out of 100 people who used a placebo (fake treatment) no longer had any warts after the treatment.
• With salicylic acid: About 39 out of 100 people who used salicylic acid no longer had any warts.

So the salicylic acid treatment helped about 14 out of 100 people get rid of their warts faster.

Side effects

Salicylic acid solutions are generally well tolerated. Mild skin irritation is common. In rare cases, the skin may become discoloured or hurt. Filing the top layer of the wart during treatment may cause a little pain or slight bleeding.

How effective is cryotherapy?

The doctor "freezes the wart off" in cryotherapy by applying liquid nitrogen to it. This substance is extremely cold and destroys the cells in the top layer of the skin. There are different ways of using liquid nitrogen. It is often done by dipping a cotton swab in the liquid nitrogen and holding it against the wart for several seconds. This treatment is repeated several times, with breaks of at least one week between each session. The nitrogen may also be sprayed onto the wart using a small nozzle. Cryotherapy can make warts on the hands go away more quickly. A review of studies showed the following results after three months:

• Without cryotherapy: About 13 out of 100 people no longer had any warts
• With cryotherapy: About 49 out of 100 people no longer had any warts.

Studies didn't find cryotherapy to be more effective than waiting (no treatment) when used to treat warts on the soles of the feet.

Side effects

Cryotherapy usually hurts a bit, and it often leaves a blister. Sometimes it also causes scarring, but any scars are barely visible after a while. Mild skin irritation or discoloration occasionally occurs.

People with diabetic foot problems or peripheral arterial disease shouldn't have cryotherapy for warts. The treatment could lead to nerve damage or poorly healing wounds on their feet. People with Raynaud's disease are also advised not to have this treatment.

How do salicylic acid treatment and cryotherapy compare?

Several studies have looked into whether one of the two treatments (cryotherapy or salicylic acid) is more effective than the other. Most of them didn't find any significant differences.

The success of wart treatments can depend on several factors, including how long the wart is frozen for and how often the treatment is done – or how strong the salicylic acid solution is, and how often and for how long it is applied. Because so many factors are involved, more research is needed to say which treatment is most likely successful.

What are the other treatment options?

Many other wart treatments are available. But none of them have been convincingly proven to be effective or to have many advantages over salicylic acid or cryotherapy. Many of these treatments haven't been studied at all, or – if they have – the results are contradictory.

Some of the treatments are pretty complex and have several side effects. In Canada, not all of them are covered by the government.

For these reasons, they are only considered in some circumstances – and even then, only if the warts are very persistent and don't go away.

The treatments that haven't yet been tested in high-quality studies include:

• Special ointments and solutions: Ointments and solutions containing other medications were tested too, including 5-fluorouracil (a substance that inhibits cell growth), acyclovir and imiquimod (antiviral medications) and zinc.
• Injections using different kinds of medicine: Various medicines can be injected into the wart. These include bleomycin and 5-fluorouracil (both drugs inhibit cell growth), interferons (medications that affect the immune system) and specific antigens (substances that, like vaccines, trigger an immune response).
• Curettage: Curettage involves cutting or scraping warts off with a particular instrument. The wart is often first treated with a salicylic acid plaster or solution.
• Laser surgery: The wart is heated and destroyed using a laser beam. This treatment can cause scarring.
• Pulsed dye laser treatment: This treatment involves using a laser beam to heat and destroy the narrow blood vessels that supply blood to the wart. The aim is to stop the skin cells from multiplying.
• Erbium YAG laser: This is a laser treatment that aims to destroy the wart cells by strongly heating the fluid in them for a short time.
• Photodynamic therapy: First, a gel is applied to the wart and left on for about three hours. The gel contains a particular chemical substance that light activates to destroy the wart tissue.