Many people notice small, rough, circular spots on the bottom of their feet that are often called “fish eyes.” At first glance, these lesions may look like simple calluses caused by pressure or friction. Because they usually appear on areas of the foot that bear weight, such as the heel or the ball of the foot, many people assume they are nothing more than hardened skin.

However, medical experts explain that these spots are often plantar warts, a common skin condition that can easily be mistaken for calluses. Although they may appear similar on the surface, plantar warts have a completely different cause and behavior.

Understanding what these growths actually are, how they form, and why they appear can help people recognize them early and seek appropriate treatment if necessary.

What Causes Plantar Warts?

Unlike ordinary calluses, plantar warts are caused by a viral infection. The virus responsible is the human papillomavirus (HPV), a group of viruses that infect the outer layer of the skin.

HPV can enter the body through tiny cuts, scratches, or weak spots in the skin on the bottom of the foot. Once inside the skin, the virus infects the cells in the outer layer and begins to stimulate abnormal growth.

Instead of growing at a normal rate, the infected skin cells multiply rapidly, creating a thickened area that forms the wart.

Because plantar warts appear on weight-bearing parts of the foot, the pressure from standing and walking pushes the wart inward rather than outward. This inward growth is why plantar warts sometimes appear deeply embedded in the skin.

Why People Say Plantar Warts Have “Roots”

Many people believe that plantar warts have roots that grow deep into the foot. In reality, this is a misconception.

Plantar warts do not grow roots like plants. However, the infected tissue can extend deeper into the skin layers, which makes the wart appear anchored in place.

This deeper growth can also make the wart more difficult to remove compared to warts that appear on other parts of the body.

The Tiny Black Dots Inside the Wart

One of the most distinctive features of a plantar wart is the presence of small black dots in its center.

These dots are often mistaken for seeds or roots, which is why plantar warts are sometimes referred to as “seed warts.” In fact, these dark spots are actually tiny clotted blood vessels that supply blood to the wart tissue.

When pressure is applied while walking or standing, these vessels can cause discomfort or tenderness. This pain is often one of the key signs that the lesion may be a wart rather than a simple callus.

How to Tell the Difference Between a Wart and a Callus

Although plantar warts and calluses may look similar, there are a few important differences.

With a callus, the natural skin lines of the foot usually continue smoothly across the thickened area.

However, with a plantar wart, the wart often interrupts these skin lines. The normal pattern of the skin may appear distorted or broken.

Additionally, calluses typically do not contain black dots and usually do not cause sharp pain when squeezed from the sides.

Plantar warts, on the other hand, may be tender and can feel painful when pressure is applied directly.

Who Is Most Likely to Develop Plantar Warts?

Plantar warts can affect people of all ages, but they are particularly common among:

• Children and teenagers

• Athletes

• Individuals with weakened immune systems

Young people often develop plantar warts because their immune systems are still learning to recognize and fight off certain viruses.

Athletes may also be at higher risk because they frequently use locker rooms, public showers, and shared sports facilities.

How the Virus Spreads

The HPV virus that causes plantar warts spreads most easily in warm, moist environments.

Places such as swimming pools, locker rooms, public showers, and gym floors provide ideal conditions for the virus to survive.

Walking barefoot in these areas increases the risk of infection because the virus can enter the skin through microscopic cracks or small injuries.

It is important to note that exposure to HPV does not always lead to a wart. The development of a wart often depends on the strength of a person’s immune system.

How Plantar Warts Develop Over Time

Many people do not realize they have been exposed to HPV until weeks or even months after the infection occurs.

Plantar warts usually begin as small rough spots on the skin. Over time, the area may become thicker and more noticeable.

Some warts appear alone, but others may grow in clusters.

When multiple plantar warts develop close together, they are known as mosaic warts. These clusters can spread across a larger area of the foot and may be more challenging to treat.

Why Plantar Warts Can Be Painful

Pain is one of the most common symptoms of plantar warts.

Because they form on weight-bearing areas of the foot, walking or standing places pressure on the wart. This pressure pushes the wart deeper into the skin, which can irritate the surrounding nerves.

Many people describe the sensation as feeling like stepping on a small pebble inside the shoe.

For individuals who spend long hours standing or walking, the discomfort may become more noticeable.

Do Plantar Warts Go Away on Their Own?

Although plantar warts may look concerning, they are usually harmless.

In many cases, the body’s immune system eventually recognizes the virus and eliminates it naturally. However, this process can take several months or even years.

Because plantar warts are contagious and sometimes painful, many people choose to treat them instead of waiting for them to disappear on their own.

Common Treatment Options

Several treatments are available for plantar warts.

Salicylic Acid Treatments

Many over-the-counter wart treatments contain salicylic acid, which gradually removes the thickened layers of skin.

By slowly dissolving the wart tissue, these treatments allow healthy skin to grow in its place.

Cryotherapy

Another widely used treatment is cryotherapy, which involves freezing the wart using liquid nitrogen.

This procedure is typically performed by a healthcare professional. The freezing process destroys the infected tissue so that the body can replace it with new, healthy skin.

Advanced Medical Treatments

If the wart does not respond to standard treatments, doctors may recommend other options such as:

• Laser therapy

• Immune-stimulating medications

• Minor surgical removal

These treatments are usually reserved for stubborn or recurring cases.

Preventing Plantar Warts

Preventing infection is an important part of managing plantar warts.

Simple habits can significantly reduce the risk of exposure to HPV.

These include:

• Wearing flip-flops or sandals in public showers and locker rooms

• Keeping feet clean and dry

• Avoiding direct contact with someone else’s wart

• Not sharing personal items like shoes, socks, or towels

It is also important not to pick, scratch, or cut a wart, as this can spread the virus to other parts of the foot or to other people.

Covering the wart with a bandage and maintaining good hygiene can help prevent the infection from spreading.

Final Thoughts

The small, rough spot often referred to as a “fish eye” on the bottom of the foot is usually not just a simple callus. In many cases, it is actually a plantar wart caused by a viral infection.

Although these lesions may resemble thickened skin, their cause, structure, and behavior are very different.

Recognizing the signs of plantar warts—such as black dots, disrupted skin lines, and pain when walking—can help people identify the condition early and choose the right treatment.

By understanding how plantar warts develop and how the virus spreads, individuals can take steps to protect their feet and reduce the risk of infection.

While plantar warts are generally harmless, proper care and prevention can help keep them from becoming a persistent or uncomfortable problem.