Symptoms and causes

What is it?

Warts are common benign skin growths caused by a viral skin infection, namely the human papilloma virus (HPV).

How can you contract it?

Warts are contagious through direct skin contact. It is easier to get infected in particular when there are small wounds on the surface of the skin. Warts can spread as a group (mosaic shape) or elsewhere on the body (e.g. around the mouth when biting nails).

Warts thrive in humid and warm environments, where you can get infected, for example, in swimming pools or showers when another person with the condition was in the same place before you.

Characteristics and symptoms

Warts look like a round to oval callous thickening of the skin. They usually show up on the feet, hands, face, knees and elbows, but in principle they can occur anywhere on the body. Sometimes they are skin-coloured and flat (flat shape) and sometimes they are more filiform (filiform type).

Warts are most common in children because they have not yet built up an immune system to repel them, but adults can also become infected. These growths usually disappear by themselves over time, but the lesions can be painful and/or disruptive or spread very quickly, which are reasons to treat them anyway.

Another species of warts are the mollusca contagiosa, also known as water warts, dome shaped warts or pearl-like warts. These are caused by another virus (pox type). They usually appear in young children as large and shiny pinhead balls. They are found more often in children who have eczema. Treatment can consist of scooping out and applying a product. They usually disappear spontaneously.

Diagnosis and treatment

Diagnosis

The diagnosis of a wart is made based on what the dermatologist sees with the naked eye and usually also with the dermatoscope. Sometimes the thick, callous skin has to be removed first in order to obtain a better look, but this is not painful.

Treatment

Warts do not always have to be treated. After all, they are not harmful and, in two out of three cases, they disappear spontaneously within two years in children. Unfortunately, warts are often more persistent in adults. If a wart is unsightly or painful, for example, because it is at a pressure point in the heel, it is of course better to have it treated.

There are various treatment options:

  • Ointments or liquid solutions to apply at home.
  • Freezing off: the warts are touched up with liquid nitrogen at -196°C, which destroys the tissue. The treatment must be repeated several times. A liquid or cream (usually based on salicylic acid) can be prescribed between two treatments.
  • Because freezing is painful, or if freezing does not bring about sufficient recovery, treatment with a solution based on cantharidine may be appropriate. This is a substance that causes blisters. The product has to work for six to eight hours under a plaster and is then washed off. Afterwards, a painful blister can develop. If it is very bothersome, it is better to puncture and disinfect the blister.
  • For very stubborn warts, the dermatologist can treat them with bleomycin using scratches or an injection. This is a form of local chemotherapy that causes the cells to die off.
  • A fourth treatment option is laser, especially the CO2 laser. This is preferably used in solitary verrucae in adults. Healing takes a few weeks.

Warts rarely disappear completely after a single treatment. Usually the therapy has to be applied several times, with the wart becoming smaller each time after each treatment.

Dr De Smet with a freezing tool.

Treatment centres and specialisations

Dermatology

Latest publication date: 21/01/2021
Supervising author: Dr Van Autryve Els