Painful calluses (thickened skin), normally occur on areas of pressure associated with prominent bones. There are 4 types commonly seen: tylomas, intractable plantar keratosis (IPK), porokeratosis, and plantar warts. Each have specific characteristics, and may be difficult to distinguish. Painful calluses are created in response to pressure and/or shear force in the skin, while warts are a viral infection.
Calluses are formed to protect the skin from breaking down and causing open wounds. Areas of high pressure and shear force cause the dermis to protect itself by creating more skin. There are different types of painful calluses which develop on the toes and feet. Some tumors can mimic a callus, like amelanotic melanomas, and can be fatal. If a lesion suddenly appears, and changes by growing in size; changes in colour; ulcerates; and/ or has borders becoming irregular; it needs to be addressed by an experienced doctor, and biopsied immediately. It is important you inform your physician of any changes, and take pictures, so there is a reference point. Chances are, it is nothing serious, but there are horror stories…
Also known as flat calluses, tylomas are one of the most common types of calluses. They are characterised by uniformly thickened skin over prominent bones, heel, or other pressure areas of the foot. They do not have deep cores, and typically are not as painful as IPK’s. Caused by shear force, this type of thickened skin lesion is widespread in athletes, people with large bony prominences, and overweight persons. Shear force is the rubbing of skin between a bone on the inside, and an object of pressure outside the skin, which is caught in the middle.
Tylomas can become thick, dry, and tend to crack, if left untreated for extended periods. Conservative treatment of them includes: offloading pressure, exfoliating creams, proper fitting shoes, cushioning, orthotics, and in some cases, shoe modifications. Many times a combination of these techniques are indicated. Surgical treatment of tylomas is centered around reducing pressure, and varies with the cause.
IPK’s are usually much more painful calluses though similar in superficial appearance. They are caused by pressure and shear force, rather than shear force alone, and have a deep core present, which becomes visible when they are debrided (trimmed). The core usually communicates with a sharp bony projection or focalised pressure area. The bony projections can be caused by arthritis; lack of a fat pad on the foot; or a fracture that did not heal properly. These types of skin lesions are extremely painful to walk on; in fact, patients usually say it feels like there’s a pebble in their shoe.
Intractable Plantar Keratosis Treatment
Conservative treatment of IPK’s consists of: debridement or trimming the thickened skin, and removing the core; offloading; cushioning; use of orthotics; and shoe modifications. IPK’s are very difficult to debride correctly, because the core must be removed in order to achieve relief. However, the location and bones involved, often dictate the preferred modalities. Surgical Treatment for IPK’s is much like the surgical treatment of tylomas, and focuses on reducing projections of bone.
Porokeratosis can appear as a single or multiple lesions over any part of the bottom, or plantar surface of the feet . Very similar to intractable plantar keratosis, the cause however, has yet to be determined. It is also not associated with any particular type bony prominence, structural problem in the foot, or virus. They look quite similar to IPK’s, with a deep core with thickened skin surrounding it, but there is no black dot present as obtains in plantar warts. Some doctors believe porokeratosis is related to foreign bodies that have penetrated into the dermis, causing the skin to produce a protective deposit of skin. People describe this discomfort as feeling as if there were several pebbles stuck to the bottom of their foot, or in their shoe.
It can become very painful over time depending on the location. Several different treatments have been attempted over the years, including injections into the base of the lesions with dehydrogenated alcohol; debridements; and exfoliating agents. Debridement can be painful, but often gives immediate relief when done correctly. In order to debride porokeratosis correctly, it is important that the core of the lesion is removed. Using a pumice stone or other abrasive material, only removes the outer surface, not the core. Minimal relief is achieved from this type of debridement.
Your feet mirror your general health . . . cherish them!