Causes of Plantar Warts on the Feet

Aside from thickened skin or calluses, the soles of the feet are at risk of developing corns. This skin condition causes the skin on the soles of the feet to thicken and become painful when pressed. Learn about the symptoms, causes, and treatment options below.

What are corns?

Corns, also known as clavus, refer to a type of skin condition characterized by hard lumps that typically appear on the soles of the feet. Corns are usually small with a central point.

There are two types of corns: those caused by a virus and those caused by friction. The type caused by a virus is called plantar warts.

Plantar warts are further divided into two types:

- Solitary warts: These warts usually appear as a single wart but often grow larger.

- Mosaic warts: These consist of a group of small warts that grow close together and are harder to treat.

On the other hand, corns caused by friction and pressure are referred to as corn.

Corns caused by friction and viral infection share a similar appearance: hard, rough, and thickened lumps on the feet.

Generally, clavus is not a serious health issue, but the lumps can cause discomfort or pain.

This type of skin condition is very common. Typically, clavus affects children aged 12–16 years old.

However, this condition can affect anyone at any age, even infants.

Signs and symptoms of corns

Various signs of this condition include:

- The growth of small, fleshy, and rough lumps,

- Hard and thickened skin (callus) formed on the skin,

- Black dots commonly referred to as wart seeds, and

- Hard, rough, and raised lumps.

Usually, plantar warts appear on the heels and other weight-bearing areas of the feet. Because they form on the feet, they can cause pain when standing or walking.

Meanwhile, corn-type clavus can appear on areas of the feet that often bear weight, such as the tops, sides, or between the toes. Lumps of this type usually feel painful when pressed.

When should you see a doctor?

You should contact a doctor if you experience one or more symptoms, such as painful lumps and changes in appearance and color.

Consult a doctor immediately if the lumps become inflamed, bleed, or increase in number despite treatment for more than three weeks.

If you have diabetes, consult a podiatrist (foot specialist) when this problem first appears and shows symptoms on your feet.

Causes of corns

Corns can be caused by two things, explained below.

1. Human papillomavirus (HPV)

Plantar warts are caused by an infection with the human papillomavirus (HPV).

This virus usually enters the body through open wounds. You can also contract this virus through:

- Direct contact with an infected person,

- Using socks or shoes worn by an infected person, and

- Spending extended time in warm, moist environments.

Once the virus enters the skin, it can grow and spread, accelerating the growth of cells on the skin's surface. It’s difficult to know when or where you were exposed to the virus.

This condition caused by HPV has various names, such as common warts, flat warts, filiform warts, and periungual warts.

2. Pressure and friction

This condition can also be caused by pressure and friction on the feet. This condition is commonly referred to as corn. Clavus typically develops due to repeated pressure and friction.

Wearing the wrong shoes, such as those that don’t fit properly, can press on the feet, causing friction. If left unchecked, corns can develop.

Shoes that are too loose allow the feet to slide and rub against the shoes, which can also lead to the formation and growth of corns.

That's why it’s essential to wear properly fitting shoes.

Risk factors for corns

Corns caused by HPV are more likely to occur in the following groups:

- Children and teenagers,

- People with weakened immune systems,

- People who habitually bite their nails,

- People who have undergone organ transplants,

- People who have had corns before, and

- People who walk barefoot with cracked feet.

Meanwhile, the risk of developing corns due to foot friction can increase due to the following conditions: