What causes plantar warts?

If you’ve ever dealt with stubborn plantar warts, you’re not alone. These pesky small growths affect millions of people around the world. In fact, they’re one of the most common foot complaints. They’re a nuisance at best; a painful obstacle at worst. And they’re especially troublesome for those who spend a lot of time on their feet. The good news? With a bit of understanding, you can better manage—or even avoid—this common skin condition. Let’s start with what causes plantar warts. 

Understanding Plantar Warts

Plantar warts are caused by a strain of the human papillomavirus (HPV). This strain infects the outer layer of the skin, typically on the soles of the feet. Unlike other types of warts, which can appear pretty much anywhere on the body, plantar warts thrive in the warm, moist environment created by shoes and socks. 

They’re most often found on weight-bearing areas of the foot, such as the heels or the balls of the feet. The pressure from standing and walking can push the warts deeper into the skin. This leads to the telltale pain or tenderness people experience when on their feet. Ouch! 

People of all ages can get plantar warts, but they’re most common in children and teens, as well as people who have weakened immune systems. People who walk barefoot in communal spaces (think locker rooms, swimming pools, hot tubs, or gym showers) are at a higher risk as the virus spreads easily in warm, wet places. 

What makes plantar warts different from other types of warts? It’s their key characteristic: their flat or inward-growing appearance, often with tiny black dots at the center. These dots are actually small clotted blood vessels. The warts themselves tend to feel rough to the touch, and they’re sometimes surrounded by hardened skin as the body tries to protect itself from the uncomfortable irritation. 

Knowing what to look for can make all the difference when managing plantar warts effectively. Whether you’re just noticing a new bump or have been battling discomfort for a while, understanding the causes and characteristics is the first step toward treatment and, eventually, relief. 

What Causes Plantar Warts?

Surprisingly, there are more than 100 different strains of HPV. However, plantar warts specifically arise from the types that prefer warm, moist conditions, as commonly found on the feet. Not everyone who is exposed to these strains develops warts. That said, the virus is highly contagious, and certain environments are prime breeding grounds.

HPV tends to spread through indirect contact with surfaces that contain the virus. The most common hotspots for transmission include locker rooms, public pools, gym showers, and even yoga studio mats. These areas provide the perfect environment for HPV to thrive. Why? Because these warm, enclosed, humid environments, along with bare feet, help sustain the virus. Moist surfaces, such as pool decks and shower floors, make it easier for the virus to linger long enough to transfer to a new host. Finally, if the skin is vulnerable due to cuts, scrapes, or even minor abrasions (from walking barefoot), it’s easier for HPV to enter into and infect the skin. 

Again, not everyone who comes into contact with HPV will develop plantar warts. Several factors influence susceptibility, including: 

• A weakened immune system, which increases the chance of infection, and people with chronic illnesses are at greater risk.
• Because the immune systems of children and teens are still developing, they may not be fully adept at fighting off the virus. 
• Walking barefoot in communal spaces also increases the chances of contracting the virus. 
• People who sweat a lot (e.g., those with conditions like hyperhidrosis) may also be more prone to infection because their skin is more likely to be warm and damp. 
• Finally, people with dry, cracked, and damaged skin may be at an increased risk as the virus has an easier point of entry. That includes blisters or corns from ill-fitting shoes and tiny abrasions from walking on rough surfaces. 

It’s not just about keeping your feet clean (though that can help). HPV is stubborn. It can survive on surfaces for long periods, especially in areas that remain warm and damp. That said, poor ventilation and subpar cleaning practices make it even more likely you’ll be exposed to the virus. 

Recognizing Symptoms

Plantar warts are easily recognizable. However, they’re not always visible immediately. The symptoms can range from mild discomfort to significant pain that impacts daily activities. Here are the visible symptoms  to watch for: 

• Small, grainy patches of skin on the soles of the feet. They may be flat or slightly raised.
• One hallmark feature is the presence of tiny black dots within the wart. These are clotted blood vessels and are often referred to as “wart seeds.”
• Sometimes, plantar warts appear in groups. These are called mosaic warts and can cover large areas of the foot. 
• Pressure from standing or walking can cause the skin around the wart or wart cluster to thicken and harden, forming a callus. 

Planter warts can cause significant discomfort, especially when located on weight-bearing areas, such as the heel or ball of the foot. The pressure can push the wart deeper into the skin, making the pain even worse. Some people describe the sensation as similar to walking with a small stone in their shoe. While less common than pain and irritation, some people complain that the plantar warts are itchy or sensitive when touched. 

Ultimately, the discomfort can impact everyday activities. While it may seem like a minor issue at first, because they’re located on the feet, plantar warts are difficult to ignore for long. Over time, the persistent pain can make it difficult to walk or stand for long periods. This can be particularly challenging for folks who have active jobs or lifestyles. 

For those who enjoy active lifestyles, plantar warts can make running, jumping, and other movement uncomfortable or even impossible. 

To avoid the discomfort, people may unconsciously alter how they walk to avoid putting pressure on the wart. This can lead to poor posture, gait changes, and pain in other areas of the body, such as the knees, hips, and back, potentially causing chronic pain or injury over time. 

It’s also common for people with plantar warts to feel self-conscious or embarrassed, especially in situations that involve bare feet, such as swimming or yoga. 

While plantar warts are not life-threatening, leaving them untreated can lead to complications that make the problem more difficult to manage. For some, plantar warts may go away as the immune system fights off the virus. However, this can take months or even years—and ignoring the issue can lead to several challenges, such as:

• Increased pain and discomfort as the warts grow larger or multiply. The pressure on the feet can become unbearable, particularly on the heel or balls of the feet, making your usual activities increasingly difficult. 
• Spread to other areas of your body. Remember, HPF is highly contagious.  Especially if you scratch or pick at the wart, it can lead to additional warts on the feet or even spread to the hands or fingers. 
• Development of mosaic warts, which are often more challenging to treat and can cause even more pain or discomfort.
• Untreated warts can also increase the risk of secondary infections. This is especially true if the warts are repeatedly irritated, scratched, or exposed to friction. Friction that’s common from footwear, especially footwear that’s ill-fitting. As cracks or sores develop, they create an easier entry point for bacteria. To help clear the skin, you may need antibiotics or additional medical interventions. 
• Without treatment, plantar warts can become persistent and harder to remove. They can also recur more easily even after they’ve been addressed and cleared due to residual virus load within your system. 
• Again, because HPV is so contagious, it can also spread through shared surfaces. This includes communal showers, locker rooms, and yoga mats, but it also includes shared showers in your own home—to family members or roommates who likely will not appreciate the “gift.”

While not all plantar warts require aggressive treatment, and some do eventually go away on their own, addressing them early can help reduce pain and discomfort, prevent the spread to other areas or people, minimize the risk of infections, and help restore confidence, particularly if the wart is noticeable or makes you feel self-conscious. 

Diagnosing Plantar Warts

Diagnosing plantar warts is typically straightforward for healthcare providers. Both primary care doctors and dermatologists use a combination of clinical examinations and additional diagnostic techniques to confirm whether a foot lesion is indeed a plantar wart. 

The practitioner will start by looking for the hallmark signs of plantar warts—the rough, grainy texture, flat growths, and tiny black dots on the soles of the feet or skin thickening or calluses or hardened skin.  

Your dermatologist may use a dermatoscope, which is a specialized magnifying tool, to examine the wart more closely. This helps the provider identify unique features like blood vessels or patterns in the lesion to confirm it’s a wart.

In some cases, your doctor may gently shave off the top layer of the lesion with a scalpel to reveal the characteristic black dots. While this may sound scary, it is a simple and typically painless in-office procedure.

If the diagnosis is uncertain, or the lesion doesn’t respond as expected to typical treatments, your doctor may recommend a small skin biopsy. In other words, they’ll remove a small sample of your skin to send off to the lab to confirm the diagnosis and rule out other possible skin conditions, such as a corn, callus, or, on rare occasions, a form of skin cancer. 

Differentiating Planter Warts from Other Foot Conditions

While there are clear signs and symptoms of plantar warts, other skin conditions can have similar signs that may make it difficult to differentiate. Healthcare providers can help you determine if you have HPV or other conditions, such as:

• Corns or Calluses: Unlike warts, these don’t have the telltale black dots. They’re usually caused by pressure or friction (such as by ill-fitting shoes) and tend to have a uniform appearance. They also lack the grainy, irregular texture of a wart.
• Athlete’s Foot (Tinea Pedis): This fungal infection is also highly contagious in warm, high-moisture environments like locker rooms and saunas and causes redness, peeling, and or itching. 
• Foreign Body Reactions: Occasionally, splinters or other foreign objects under the skin can mimic warts. However, these usually have a history of injury and, again, lack the characteristics of plantar warts.
• Skin Cancer: On rare occasions, lesions on the foot could be mistaken for plantar warts. Persistent, irregular, or fast-growing lesions that bleed or change require further investigation to rule out this potentially serious concern. 

When Should You Seek Help?

Seeking help is essential for those who are experiencing significant discomfort, especially if it interferes with walking, standing, or daily activities. It’s also important to reach out to your doctor or dermatologist if your wart appears to be growing quickly, forming clusters, or spreading to other parts of the body. The same goes for lesions that are irregular in shape, bleed, or change color, which are indications it’s not a wart and could be a more concerning condition.

In addition, if you are unsure whether the lesion is a wart or could be another condition, schedule an appointment. If you have undergone treatment (including home remedies or OTC products) and the condition doesn’t improve after several weeks, you’ll also want to reach out to your healthcare team. For warts that go away with treatment but then reoccur, professional intervention may be needed to address an underlying cause. 

Treatment Options

One of the biggest challenges with plantar warts is they’re stubborn and can be difficult to treat. Fortunately, there are a variety of options available. This includes simple home remedies, over-the-counter products, and professional interventions. 

The best approach depends on the severity of the wart, how long it’s been around, and how much it impacts your life. 

If you have a mild case or a newly developing wart, you can consider home remedies. Some options include: 

• Occlusion (or Duct Tape) Therapy: This method reportedly offers mixed results and is only suitable for mild cases. It involves covering the wart with duct tape for six days. Then, soak your foot in warm water before gently filling down the wart with a pumice stone or emery board. (Remember to avoid touching any other skin while treating your wart to avoid spreading it to other body parts.) Repeat the process until the wart disappears. 
• Exfoliation: This is similar to the first method, just without the duct tape. Soak the wart in warm water for 10 to 15 minutes every day to soften the skin. Again, gently exfoliate with a pumice stone or emery board. While it may not remove the wart on its own, it may keep it more manageable and make other treatments more effective. 
• Apple Cider Vinegar: Some people seem to think apple cider vinegar can help just about anything. That doesn’t appear to be true. But, there are some reports that it could help reduce warts. However, it can also irritate the skin and make it more painful. So, if you try this method, do so at your own risk and with caution. To use this method, start by diluting the vinegar with water. Then, apply it to the wart on a cotton ball. Cover the cotton-ball-covered wart with a bandage and leave overnight. 

OTC (over-the-counter) treatments are often the first line of defense for plantar warts and have been found to be effective for many. Options include:

• Salicylic Acid: Available in liquid, gel, and patch forms; start by soaking and exfoliating the area before applying. Over time, the keratolytic agent acts to dissolve the layers of the wart. This is perhaps the most effective OTC treatment, as long as it’s used consistently on small, less severe cases.
• Cryotherapy kits: While professional cryotherapy (liquid nitrogen or dimethyl ether to freeze the wart, causing it to blister and eventually fall off) is more reliable and effective, at-home kits are available but may need to be used multiple times and are known to be less effective. 

When home remedies and OTC treatments fail, it’s time to turn to medical interventions with a dermatologist, such as: 

• Cryotherapy (freezing): A doctor applies liquid nitrogen to the wart, which freezes and destroys the infected tissue. This is considered one of the most effective methods. However, it can be painful and often requires several sessions. 
• Cantharidin: Another blistering agent, this medication is applied to the wart and then covered with a bandage as the wart blisters and eventually falls off. It appears to be effective, especially for children, and is recommended because it causes less discomfort when applied. 
• Laser therapy: Intense laser light is used to destroy the infected tissue while sealing blood vessels to cut off the blood supply to the wart. This method can be highly effective, even for resistant warts. However, it also is more costly and often requires multiple sessions. 
• Surgical removal: The wart is physically removed using a scalpel under local anesthesia. It can provide immediate results. There are, however, still risks. Namely, it may cause scarring, and you may still see a recurrence. 
• Immunotherapy: Treatments like imiquimod or injections of antigens stimulate your immune system to help it fight off the virus. This method is typically used for persistent warts or those that have been resistant to other therapies. 

Prevention Strategies for Plantar Warts

While plantar warts can be stubborn once they appear, the good news is that they’re largely preventable. By adopting some simple lifestyle practices, such as good hygiene and protecting your feet, you can greatly reduce the risk of contracting the virus. 

Tip 1: Protect Your Feet in Communal Spaces: Shower shoes are a thing for good reason. Wear flip-flops or water-resistant sandals in public places like locker rooms, pool decks, and communal showers to create a barrier between your tender toes and the surfaces where the virus thrives. Even in less obvious communal areas (such as gym mats and hotel rooms), avoid going barefoot to protect your feet and minimize exposure.

Tip 2: Maintain Good Foot Hygiene: Use warm water and soap to thoroughly clean your feet every day, especially if you’ve gone barefoot in any public area. After washing, dry your feet completely. Remember to pay special attention to the area between the toes. This strain of HPV loves moist environments. 

Don’t forget to exfoliate. Removing dead skin regularly can reduce crevices where the HPV can settle in and potentially lead to warts.

Tip 3: Keep Your Feet Dry: Choose footwear made from breathable materials and change your socks daily to avoid creating an inviting environment for the virus to thrive. If you find you have sweaty feet, a foot powder may help reduce the moisture and keep your skin dry. 

Tip 4: Support a healthy immune system by eating a balanced diet, getting regular exercise, and prioritizing sleep. Optimizing your immune system is one of the best ways to encourage your body to fight off infections, including HPV.

Tip 5: Don’t share personal items, including shoes, socks, towels, or yoga mats, which can transfer the virus between people. This is especially true for public settings like gyms.

Tip 6: Regularly check out your feet (and skin in general). If you notice any unusual growths, address them early to prevent them from growing or spreading. Don’t, however, pick or scratch the skin, as this could transfer the infection to other parts of your body or others. Remember to wash your hands completely to prevent the spread if there is any infection. 

Tip 7: Practice Smart Footwear Habits: For instance, rotate your footwear daily to allow your shoes to completely dry out between wears. And avoid wearing tight or poorly fitting shoes that can cause blisters, friction, or cuts that can make your feet more vulnerable. 

Living with Plantar Warts

Plantar warts are a common condition, but that doesn’t mean they aren’t frustrating to deal with. The key is to address them early and consistently to minimize discomfort and prevent the spread. Fortunately, you do have options to help find relief and get back on your feet—comfortably. 

Remember to stay consistent with your treatment. Most treatments can take weeks of consistent application before they show results. In the meantime, keep the warts covered with a bandage to both reduce the risk of spread and provide some protection. Extra padding, such as moleskin or cushioned insoles, may help alleviate the pressure on the warts and minimize pain. And don’t forget to keep your feet clean and dry. 

Author: Larry Norris

Dr. Don Mehrabi is a board-certified dermatologist providing medical care to patients in the Beverly Hills, California area at BH Skin Dermatology.