Q: I have been treating what I am sure are two warts on the bottom of my foot. On the ball of my foot, I have two spots with tiny black dots inside, and those areas are tender when I walk without shoes on. I purchased an over-the-counter freezing kit to remove the warts and used it four times, which is the maximum amount recommended on the packaging, but it made no difference. I don’t have a family doctor at this time. Is there anything else I can try?
Plantar warts are caused by certain strains of the human papillomavirus (HPV) and are very common on the weight-bearing parts of the foot. Unlike common warts that grow outward and often have a raised, cauliflower-like appearance, plantar warts are pushed inward by the pressure of standing or walking. As a result, they usually remain relatively flat. Over time, as the wart thickens, the pressure from walking can make it increasingly tender. The small black dots visible within the wart are tiny, clotted blood vessels, sometimes referred to as wart seeds, and they are a classic feature that helps identify plantar warts.
Over-the-counter freezing kits, such as the one you tried, are often appealing because they advertise fast and convenient results, but they do have limitations. They typically use dimethyl ether or a similar substance as the freezing agent, which does not reach the extremely cold temperatures achieved by liquid nitrogen. Liquid nitrogen is used in clinical settings and is far more effective at destroying wart tissue. Because of this difference, over-the-counter freezing kits tend to be less successful, particularly for plantar warts, where the skin is thick and calloused.
For plantar warts, the most effective over-the-counter option is usually a salicylic acid-based product. Salicylic acid is a keratolytic agent, meaning it works by gradually breaking down and peeling away layers of infected skin. Since the soles of the feet have thicker skin, products containing higher concentrations of salicylic acid are recommended. In most cases, a strength between 20 and 40 percent is appropriate. These products are widely available in pharmacies and come in several forms, including liquids, gels, and medicated pads. Liquids and gels are typically applied once to twice daily, while medicated pads are usually changed every 48 hours. No single form has been shown to be more effective, but medicated pads may offer added cushioning that can help reduce pressure and discomfort while walking.
Proper skin preparation is an important part of successful treatment. Before each application, soak your foot in warm water for 5 to 10 minutes to soften the outer layer of skin. Dry the area thoroughly, then gently file the softened dead skin over the wart using a pumice stone or emery board. This helps the medication penetrate deeper. Consistent application is necessary, and it is normal for treatment to take at least 8 to 12 weeks.
It is also important to remember that plantar warts are contagious. The virus can be shed and survive on surfaces such as floors, towels, socks, and the inside of shoes. HPV thrives in warm, moist environments, which is why shared spaces like showers, locker rooms and pool decks are common places for transmission. To reduce the risk of spreading the virus to others or reinfecting yourself, keep your feet clean and dry, change socks daily, and allow shoes to dry completely between wears. Washing socks, slippers, and shoe insoles in hot water and wearing sandals in shared spaces can help limit the spread. Household floors and bathroom surfaces should also be cleaned regularly with a disinfectant that is effective against viruses.
If you have used a salicylic acid product consistently for 12 weeks and the wart has not resolved, or if the area becomes increasingly painful, starts bleeding, or appears to be spreading, it is appropriate to seek professional care. Since you do not currently have a family doctor, a podiatrist is an excellent option. Podiatrists specialize in foot and ankle conditions and can provide treatments such as stronger topical therapies, cryotherapy with liquid nitrogen and minor procedures if needed.
Finally, not everyone should attempt to treat warts at home. Anyone with diabetes, poor circulation, nerve damage in the feet, or a weakened immune system should avoid over-the-counter wart treatments altogether. In these situations, even minor skin injuries can lead to complications, and professional assessment and monitoring are needed.
Erin Thompson (BSc, BScPharm) is a graduate of Dalhousie University and a community pharmacist practicing at Shoppers Drug Mart in Quispamsis N.B. Her opinions expressed in this column are published for educational and informational purposes only, and are not intended as a diagnosis, treatment or as a substitute for professional medical advice, diagnosis or treatment.