What are the treatment options for warts?

Salicylic acid solutions are applied to the skin several times per day over a number of 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 – for instance, with a nail file. 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.

Salicylic acid solutions are generally well tolerated. Mild skin irritation is common. In rare cases the skin may become discolored or hurt.

Filing the top layer of the wart during treatment may cause a little pain or slight bleeding.

In cryotherapy, the doctor "freezes the wart off" by putting liquid nitrogen on it. This substance is extremely cold and destroys the cells in the top layer of skin. There are different ways to apply the liquid nitrogen. It is often done by dipping a cotton swab in the liquid nitrogen and then 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.

But cryotherapy wasn't found to be more effective than waiting (no treatment) when used for the treatment of warts on the soles of the feet.

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

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

You can also buy a wart-removal pen at a pharmacy (without a prescription) and use it yourself at home. These pens don't get as cold as the liquid nitrogen treatment used at the doctor’s. Their effectiveness has not yet been put to the test in scientific studies.

The U.S. regulatory agency FDA issued a warning that cryogenic wart-removal pens contain flammable substances, and that there have been some cases of burns while using them.

A number of 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 a number of different 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 in order to be able to say which treatment is most likely to be successful.

Many other wart treatments are available. But none of them have been convincingly proven to work, or to have any 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 quite complex and have a number of side effects. In Germany, not all of them are covered by statutory health insurers. For these reasons, they are only considered in exceptional 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, or where research hasn’t led to clear conclusions, include:

• Special ointments and solutions: Ointments and solutions containing other medications were tested too, including 5-fluorouracil (a substance that inhibits cell growth), aciclovir 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 (drugs that affect the immune system) and specific antigens (substances that, like vaccines, trigger an immune response).
• Curettage: Curettage involves scraping warts off with a special instrument. The wart is often first treated with a salicylic acid plaster or solution.
• Laser surgery: Here 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 chemical substance that is then activated by light so that it can destroy the wart tissue.

It used to be quite common to remove warts by simply cutting them out, but this is rarely done nowadays since it can cause infection or scarring. And new warts may grow back after surgery.

A number of rather unusual wart treatments are available. Some people believe that they have got rid of their warts by using these treatments. But warts usually disappear on their own without any treatment as soon as the body has built up enough of an immune response against the viruses. So it's very difficult to judge the effectiveness of these treatments without comparing them with something else, such as a placebo. Good-quality studies are needed to do so.

A group of researchers from England tested the effectiveness of “distance healing” for treating warts. The study involved 84 people who had an average of eight warts each. One half of the participants were assigned to “distance healers,” who “channel energy” to the participants without having direct contact with them. The other half didn’t have any treatment. The outcome: After six weeks, the people in the distance-healing group still had an average of eight warts each. Those who didn’t have any treatment had one fewer each on average.

Many of the other unconventional methods, such as “talking”/ “charming” warts off or treating them with slugs, haven't been scientifically proven to work. Several studies comparing homeopathic remedies with placebos (fake drugs) showed that the homeopathic treatment had no effect on warts.