Warts and verrucas

Verrucas are warts found on the feet

Warts are very common and appear as small rough lumps or growths on the skin. They are usually harmless and in most cases eventually go away on their own. Common treatments for warts include applying a paint or gel, or freezing with liquid nitrogen or a cold spray.

Types of warts

There are different types of warts, which differ in appearance and occur on different parts of the body.

Name Location & appearance
Common warts Common warts are usually found on the backs of fingers or toes, around the nails, and on the knees. They sometimes look like 'a cauliflower'. These are also called butcher’s warts.
Verrucas or plantar warts Verrucas or plantar warts are found on the soles of the foot. They grow inward into the foot and can be quite painful when you stand or walk. 
Plane warts Plane warts have a flat surface. They are often found in clusters, and tend to appear in a line.
Filiform warts Filiform warts are on a long stalk like a thread and commonly appear on the face.
Mucosal warts Oral warts can affect the lips and even inside the cheeks, where they may be called squamous cell papillomas.

What causes warts?

Warts are caused by different strains of the human papillomavirus (HPV). The strains of HPV that cause harmless warts on your hands, legs or feet are different to those that cause genital warts and cervical cancer.  

How do warts grow?

  • Warts form when the HPV virus infects the top layer of your skin and causes your skin cells to grow very fast.
  • Sometimes warts occur in isolation, with only one or two warts developing on the skin; sometimes they occur in a cluster, where several occur in the same area of skin.
  • Warts can differ in size from a tiny dot (few millimeters) to a larger lump (over 1 cm).

Are warts contagious?

  • Warts are not considered very contagious, but they can be spread by close contact with someone. 
  • The virus can also be passed on to someone else by touching contaminated objects or surfaces, such as the area surrounding a swimming pool or shower, towels, razors or other personal items.

What increases your risk of getting warts?

  • Warts are common in school-aged children, but can occur at any age, especially in people take medications that suppress the immune system.
  • You are more likely to get warts in places where your skin is broken, such as through cuts, hangnails, closely bitten nails, or scrapes.
  • Some types of the virus thrive in warm, damp places, such as showers, locker room floors, and swimming pool areas.
  • Warts that you get on your feet (plantar warts) are common in swimmers whose feet are not only moist and softened but are also scratched and broken by rough pool surfaces.

What are the treatment options for warts?

Warts are usually harmless. Most often they go away on their own within months or years. But if they spread or cause pain, or if you don't like the way they look, you may want to treat them. 

Treatment can often clear warts more quickly, but treatments are time-consuming and some can be uncomfortable or painful. The most commonly used treatments are wart paints or gel (also called topical treatment) and freezing treatment.

Wart paints or gel

Wart paints or gel are topical treatments that contain salicylic acid, podophyllin or similar compounds.

  • They are usually applied directly onto the wart once daily.
  • They work by removing the dead surface skin cells.
  • They usually make the wart smaller and less uncomfortable.
  • About 70% of warts (7 out of every 10 warts) improve within twelve weeks of daily applications.

It is very important to carefully follow the instructions on the packaging because applying these treatments to normal skin that is not affected can cause skin burn. 

Freezing treatment 

This is when liquid nitrogen is sprayed or applied to the wart. Liquid nitrogen is very cold and the freezing and thawing destroys the wart.

  • It is normally repeated every 1 to 3 weeks.
  • Freezing treatment is quite uncomfortable and may cause blistering of the skin for a few days or weeks.
  • It is very effective with 70% (7 out of every 10 warts) improving after 3 to 4 months of regular freezing.
  • A hard freeze using liquid nitrogen might cause a permanent white mark or scar. It can also cause temporary numbness.
  • An aerosol spray with a mixture of dimethyl ether and propane (DMEP) can be purchased over the counter to freeze common and plantar warts. It is important to read and follow the instructions carefully.

Other treatments for warts

If the above treatment options do not clear your warts, then other methods may be tried. This can include having the wart surgically removed, or other treatments that 'burn' the wart off. These treatments are usually only done by specialists if other options have failed.

Learn more about warts

The following links provide further information on warts and verrucas. Be aware that websites from other countries may contain information that differs from New Zealand recommendations.

Viral warts DermNet NZ
Warts and Verrucas Patient Info, UK

Credits: Editorial team.