Warts are a type of non-cancerous skin growth. Although usually harmless, warts can cause pain and embarrassment.

A 2019 article indicates that warts can occur on numerous parts of the body. According to the American Academy of Dermatology Association (AAD), warts are typically rough and skin-colored, although they can also be dark, smooth, and flat.

Although warts can be itchy, painful, tight, or cause a feeling of pressure, they do not usually produce any other symptoms. Different strains of human papillomavirus (HPV) cause warts.

This article will look at the different types of warts, as well as causes, treatments, and how to prevent them.

The location of the wart and its appearance will determine which sort of wart a person has:

Common warts

According to the AAD, common warts often develop on the fingers, nails, toes, or the back of the hand. Sometimes, common warts develop on the knees.

Common warts usually occur in areas of broken skin, such as around bitten fingernails or where someone has pulled a hangnail.

Common warts are rough in texture and can vary in size from a pinhead to pea size. Some common warts contain tiny, seed-like black dots.

A common wart that resembles a cauliflower in appearance is known as a butcher’s wart.

Plantar warts

Plantar warts usually occur on the feet or ankles. Doctors often refer to plantar warts that grow on the soles of the feet and toes as verrucas.

Plantar warts resemble thick, calloused skin, often with black dots on the surface.

Because plantar warts tend to develop on the soles, they are often flat, and a person can push them inward as they walk. This inward growth can cause pain and create the feeling of a pebble stuck in the person’s shoe.

According to a 2019 article, mosaic warts appear in clusters, usually on the ball of the foot or the toes. However, mosaic warts can cover areas anywhere on the sole of the foot.

Mosaic warts are paler and flatter than plantar warts.

Flat warts

Flat warts, or plane warts, are slightly raised and smooth in appearance. Flat warts can be light brown and develop most often on the forehead and cheeks. However, flat warts can also develop on the hands, lower arms, and legs.

Filiform warts

According to the AAD, filiform warts are long and spiky and often appear around the eyes, nose, and mouth. Filiform warts grow quickly.

Periungual warts

Periungual warts grow around the finger and toenails, usually spreading underneath the nail. According to an article in Photodiagnosis and Photodynamic Therapy, the location of periungual warts can make them difficult for a person to treat.

Genital warts

Genital warts are a form of sexually transmitted infection (STI). The Centers for Disease Control and Prevention (CDC) state that genital warts usually cause no additional symptoms. However, depending on the size and location, they can cause pain or itchiness.

Genital warts range in color from pink to dark brown and can be flat, bumpy, or grow from the skin on stalks. A 2015 article notes that genital warts can occur in the following locations:

  • vagina
  • vulva
  • cervix
  • urethra
  • penis
  • scrotum
  • anus

Warts caused by the same strain of HPV can also occur on the lips or inside the mouth. These warts are called mucosal warts.

The HPV strain that causes genital warts can also cause certain types of cancer. For this reason, a person who thinks they may have genital warts should see a doctor immediately.

HPV viruses cause warts. Warts occur when one of these viruses infects the top layer of the skin.

The AAD state that warts are more likely to develop when a person has a small cut or other skin damage. Warts tend to spread more easily on moist skin.

Warts are contagious and can spread from person to person through direct contact with skin or by touching an object, such as a towel, that another person’s wart has touched.

Genital warts spread through sexual contact with someone who has them, via oral, vaginal, or anal sex.

According to the AAD, the people most at risk of warts are:

  • children
  • teenagers
  • people who bite their nails or pull hangnails
  • people who have a weakened immune system

A person who thinks they have a wart can visit a dermatologist. The dermatologist will inspect the wart and may perform a biopsy or conduct other treatments to remove the wart.

Warts will often clear up on their own, especially in children. However, there are treatments available.

A person with painful, stubborn, or multiple warts can visit a dermatologist for treatment. According to the AAD, the dermatologist may use one of the following treatments depending on the type of wart a person has:

Cantharidin

A dermatologist will apply cantharidin to the wart, causing a blister to form underneath. After a week or so, the person can return to the dermatologist to have the wart clipped away.

Cryotherapy

Cryotherapy involves freezing the wart off. The dermatologist applies liquid nitrogen to the skin, destroying the skin’s outer layer. As the nitrogen is extremely cold, it may cause a brief burning sensation on the skin. Cryotherapy may need several attempts.

Electrosurgery and curettage

A 2019 overview indicates that electrosurgery and curettage is an effective treatment for filiform, common, and plantar warts. This treatment involves the dermatologist burning and scraping off the wart. This method leaves a permanent scar, and 20% of warts are likely to return.

Excision

Excision is where the dermatologist cuts the wart out of a person’s body.

Laser treatment

Doctors may use laser treatment for warts that are unresponsive to other treatments. Laser treatment involves the dermatologist burning the wart off with a laser.

Topical treatment

Topical treatment involves applying a wart paint to the wart. This paint usually contains salicylic acid, which gradually removes the hardened wart skin. A person will need to apply the paint to the wart every day for up to 12 weeks.

Bleomycin

In this treatment, the dermatologist injects the wart with the anti-cancer medicine bleomycin. These injections may cause pain or nail loss if injected into the fingers.

Immunotherapy

Immunotherapy is useful if other treatments do not work on warts. A dermatologist may apply a chemical to the wart that causes a mild allergic reaction in an attempt to clear them.

When a person has genital warts, a dermatologist may also help support the immune system by using interferon to fight the wart virus.

The AAD recommend the following methods of prevention for warts:

  • wearing flip-flops or shoes in public changing areas, pools, or showers
  • avoiding touching another person’s wart
  • keeping warts on the feet dry to prevent spreading
  • avoiding picking or scratching warts as this may cause them to spread
  • avoiding shaving over a wart
  • ensuring everyone in the household has their own towels, razors, socks, etc
  • washing hands often
  • cleaning and covering cuts and scrapes
  • keeping skin moisturized to prevent drying out or cracking
  • trying not to bite nails or nail skin
  • getting an HPV vaccination
  • treating excessive sweating
  • using barrier birth control methods when having sex

In general, warts are harmless, and there are multiple treatments available to remove them.

A person with a wart should see their doctor or dermatologist if:

  • the wart is on their face or genitals
  • they have a growth they suspect is not a wart
  • they have multiple warts
  • they have itchy, burning, bleeding, or painful warts
  • they have a weakened immune system
  • they have diabetes