A Guide To Understanding the Difference Between a Wart and A Callus

corns and warts

It is common to have hard areas of skin on the bottom of the foot that can be painful with the pressure exerted by standing and walking. However, many people are often confused by whether the hard area is simply a callus, or whether it is a wart. While it may not seem so, there is a big difference between the two, and treatment is different as well. This article discusses these differences.

Corns, calluses, and warts all share the same kind of tissue on their superficial surface, and can often be confused as one another. Underneath, there is a big difference in the kind of tissue that is contained under a corn/callus, and the kind that is found under a wart. In short, a corn or callus is thickened tissue from the top compressed layer of skin that thickens in response to pressure. This pressure can come from externally, such as a poorly fitting shoe, or internally, such a prominent bone due to a foot or toe deformity. This thick tissue is called a hyperkeratosis, and a corn simply describes a hyperkeratosis on the toes while a callus is hyperkeratosis found on the bottom or sides of the foot.

A wart is something all together different. While a wart can develop out of a callous or corn, it can also form in skin where there is no excessive pressure, such as in the crease of the toes. A wart is the tissue formed when the skin becomes infected with a virus. This virus can be contracted by stepping on a skin cell containing the virus from another person, and is often transmitted in public places where people are barefoot, such as public showers, pools, and locker rooms. The virus instructs the skin to grow outward with tiny ridges, which strangulate capillary blood vessels as they grow, resulting in the little black dots people incorrectly call ‘seeds’ within the wart. The wart can rapidly grow, as well as spread new warts in the surrounding area. The tissue can also bleed in a pinpoint manner if shaved or snagged, and little cauliflower-like growths can be seen blossoming from the top of the wart in some cases.

There are several key differences in identifying whether a skin lesion is a callus or wart. Most cases have these differences, although there are some cases in which the differences are subtle, and it is difficult to tell without looking at the tissue under a microscope. These differences include pain, skin line appearance, surface appearance, and growth rate.

Pain:

Corns and callus tissue and wart tissue can be painful with pressure. However, the nature of this pain can be a little different when one examines their foot. In general, when one pushes on a corn or callus, it will hurt somewhat, while squeezing the tissue together does not cause any pain. A wart will generally be less painful to direct pressure, but squeezing it will cause more discomfort. While this difference is usually the case, there are calluses that can be tender to squeezing and warts that are more painful to direct pressure.

Skin Line Appearance:

The skin lines in the feet are similar to the skin lines, or fingerprints, in the hands. These lines are natural tension grooves in the skin surface. A callus will not push these lines aside, while a wart will create a disruption in the skin lines like a ripple around the wart. This usually cannot be seen until the callus or wart is shaved down flat, but is a fairly good indicator of the difference between the two.

Surface Appearance:

The surface of a callus and of a wart are usually somewhat different. Corn and callus tissue tends to be very hard and generally smooth, although some cracks can appear on the surface with rough contours. Some corns and calluses can have dry blood underneath the surface if the pressure is high enough, but this is usually more spread in clumps. Warts, on the other hand, typically have an irregular, bumpy surface that can appear ridged, rippled, or cauliflower-like. The wart can stick out away from the surface of the skin in a bumpy manner as apposed to the smooth mound of a callus, and will have the aforementioned dead capillaries that look like scattered small black dots. Some warts actually have moist, loose tissue as opposed to a hard callus top, and can sometimes look like there is a stalk going down into the skin.

Growth Rate:

Corns and calluses are the body’s natural response to pressure, and subsequently they grow slowly over time in response to the continued pressure of walking, or the irritation of a shoe. Warts, due to the fact that they are caused by an infection, can develop overnight. The wart itself may grow slowly over time, or it may rapidly expand and spread. Regardless, the onset of the wart is generally quick in comparison to the callus.

As mentioned before, these differences are not always present, and calluses and warts can sometimes appear similar. In these cases, a biopsy is needed to determine the actual tissue type, as treatment is so very different between the two. Corns and calluses are long-term skin lesions that can be reduced by regular filing or professional shaving, as well as reduction of the pressure by either wearing better fitting shoes or using special shoe inserts to reduce pressure on the bottom of the foot is the callus is located there. Contrary to popular belief, corns and callus cannot be permanently cut out, as the skin under the lesion is completely normal and is simply responding to pressure. Removing the tissue will only result in another corn or callus developing again after the skin heals. The underlying pressure point from the bone directly underneath needs to be surgically addressed to permanently remove the callus, and this requires either shaving of prominent bone or correction of any bone deformity present.

Warts cannot be treated in this manner, because a virus is the cause. The body must be stimulated to develop an immune response to the virus to destroy it, and only then will the wart go away. This is typically done with gentle chemical irritants applied to the skin on a regular basis to stimulate the immune system and prod it to create an antibody to kill the virus. Surgery to remove the wart is sometimes successful in providing lasting treatment, although some virus cells that have not yet formed an external wart can still remain in the surrounding skin and lead to a new wart over time.

While it can be sometimes confusing as to whether a hard area of skin is a callus or a wart, there are differences that can help make identification possible, and as one can see from the preceding description correct identification is the key to ensuring it is treated properly.

By: Dr. Kilberg

Dr. Kilberg provides compassionate and complete foot and ankle care to adults and children in the Indianapolis area. He is board certified by the American Board of Podiatric Surgery, and is a member of the American Podiatric Medical Association. Visit the practice website of this Indianapolis podiatrist for more information.