Is That a Wart, a Callus, or a Corn? — Leading St. Louis Foot Doctor Explains the Difference
Medicine is a tricky thing, where any number of seemingly similar symptoms can actually be anything in a range of highly specific disorders. Take, for example, a lesion on your foot. Is it a wart? Is it a callus? Or could it be a corn? What’s the difference and how is each one supposed to be treated? Lucky for you, podiatrists have become specialists at determining the answers to these very questions.
Misinformation abounds regarding the formation of warts. The most popular myth is that they can be contracted from handling toads and other amphibians. Another myth states that washing your hands in water used to boil eggs is a sure way to catch warts. Even the common belief that poor hygiene causes warts is not necessarily completely accurate.
In truth, warts are caused when the human papillomavirus (HPV) embeds itself in the tissues that make up the body through cuts or abrasions in the skin. Once embedded, the HPV infects the area around it and creates a benign growth. This is the wart.
Warts come in several distinct forms depending mainly on their shape and location on the body, both of which can be reliant on the specific type of HPV involved. For the purposes of our discussion, this article will concentrate only on plantar warts – those warts that most frequently affect the feet and are caused by HPV types 1, 2, 4, and 63 (out of the nearly 200 known strains of HPV).
Plantar warts are extremely common and it is estimated that anywhere from 7 to 10% of the population of the United States is infected with them. They are easy to catch as the strain of HPV that causes these warts can survive alone without a host for many months and thrive in warm, moist environments. Going barefoot at the pool or even in a shower can lead to infection and the development of a wart.
Preventing plantar warts is relatively simple. Wearing some form of footwear outside and when walking around public swimming pools, changing rooms, or showers can guard your feet from contact with HPV on the wet ground. Avoiding physical contact with the warts of another person and not sharing socks with others will also help prevent infection.
If all of this sounds utterly horrific, take comfort in the tendency for people to develop immunity to HPV as they age, so those most likely to be infected tend to be children and young adults. Older individuals are less prone to suffering from warts.
Plantar warts typically develop on the soles of feet, usually around the pressure points where the foot impacts the ground. Because of their location they are typically pushed inward, into the body, due to the pressure exerted on the feet. They manifest themselves as hard, splotchy lumps on the flesh that are painful when pressed. Tiny black spots may appear within the wart caused by small capillary hemorrhages beneath the skin.
Treatment of plantar warts is difficult at best. While the warts may be physically removed, the HPV is much more difficult to extricate and, more likely than not, traces of the virus will remain. These residual traces have the ability to grow more plantar warts. There is currently no completely reliable method of entirely destroying all of the HPV within the body.
Removal of the warts themselves becomes the podiatrist’s priority. There are three degrees of treatment depending on the severity of the warts. The first line of therapy involves cleaning the area with salicylic acid, which is extracted from the willow tree. Salicylic acid is commonly used for skin exfoliation and cleansing, as it is used in Oxy pads for acne treatment.
The second line of therapy involves attacking the warts from the outside with more destructive techniques. Cryosurgery, where a super-cold solution such as liquid nitrogen or chilled carbon dioxide is applied directly to the flesh, can quickly kill the tissues that it comes into contact with, allowing them to scab over and flake away. Laser therapy is another extremely effective option, where a small, highly-focused laser is used to cut off the blood supply feeding the wart below the surface of the skin. Intralesional immunotherapy is also an option, where an immune response is forcibly triggered within the lesion to help the body fight off the HPV at the source.
Finally, there is the third line of therapy is more invasive. Surgery to physically excise the warts from the body may be necessary in severe cases or if other treatments fail. There is also the antibiotic Bleomycin, which is intended for cancer patients. This obviously is a last-resort measure in cases where HPV infection becomes too widespread to be cured through other means. Bleomycin comes with negative side effects including fever, rash, hair loss, skin inflammation, or discoloration of the digits. Clearly this is not a preferred treatment under most conditions.
The salicylic acid method has been shown to have a high rate of effective treatment and the more destructive techniques may not even be necessary in most cases. As previously stated, HPV can still remain in the body and give rise to more warts, in which case a more targeted approach might be required.
Although they may superficially resemble warts, calluses and corns are an entirely different matter altogether. Where warts are a viral infection, calluses and corns are caused by pressure or friction acting upon a part of the foot. It might be proper to think of them with the consideration that all corns are calluses but not all calluses are corns.
Specifically, a callus is a patch of toughened skin tissue that results from repeated rubbing against another object, usually the inside of a shoe. This chaffing creates a thickened mound of hardened flesh, often times painful to the touch. The natural formation of calluses in some areas of the body, such as on the palms of the hands and on the soles of the feet, can be beneficial, since they create thickened padding that helps protect the skin in these high-impact areas. As such, calluses are not necessarily harmful but, if left unchecked, those that develop from unnatural abrasion can develop infections that could lead to further complications.
A corn is a specific type of callus that tends to develop on thinner areas of skin, such as those around the tops of the toes as opposed to the thicker flesh that makes up the heel and bottom of the foot. When irritation comes from a localized circular rubbing on these areas of thinner skin, the center of the resulting callus can open up, forming a small crater-like impression of hardened tissue.
As with warts, it is a fairly simple matter to prevent the formation of calluses or corns on their feet. All one needs to do is wear comfortable, well-fitting shoes that cause as little irritation and chaffing during movement as possible. One usually can’t go wrong with a pair of athletic shoes, which are designed to fit snuggly and, should undesirable agitation occur, extra padding can be added to better fit the shoe to the contours of your feet. These shoes should prevent the formation of calluses or corns and, if kept clean and dry, should also thwart the spread of HPV and, with it, warts.
The treatment of calluses and corns is generally more straightforward than the treatment of warts. Simply wearing better shoes that stop the chaffing will most often be enough, as the calluses will heal and clear up on their own. Corn pads can be purchased over-the-counter that provide padding while the callus heals. Once again salicylic acid can be applied to expedite the process, dissolving away the built-up lump of dead skin cells. Sanding down this lump with a foot file or a porous, volcanic pumice stone is another easy way to reduce the size of the callus. Nevertheless, calluses and corns should be checked by a podiatrist to determine the best course of action.
However, it should be noted that those with distinct foot deformations, such as bunions, may develop calluses even with proper shoes. In cases such as these, a podiatrist’s treatment of the abnormality would be the first step to reducing the likelihood of calluses from occurring.
Warts, calluses, and corns are three very common problems that afflict the feet of millions of Americans every year and yet are remarkably easy to prevent. In all three cases taking care to protect the feet by wearing clean, dry, proper fitting shoes should be sufficient to avoid ever being beset by warts, calluses, or corns.
If you have warts or are concerned with calluses and corns on your feet, and if you live in or near St. Louis, MO, be sure to contact the area’s leading podiatrist, Richard Wittock, DPM, either by calling today or by clicking here to request an appointment.