Corns and calluses are areas of thick skin that result from excessive pressure or friction over a boney prominence. When these areas develop on the bottom of the foot they are called calluses. When they occur on the top of the toes they are called corns. They can also occur between the toes, the back of the heels and the top of the foot. The thickening of the skin is a normal body response to pressure or friction. Often times they are associated with a projection of bone called a bone spur. Not all areas of thickened skin are corns or calluses. Planter’s warts, inclusion cysts and porokeratoses also cause a discreet thickening of the skin that resembles corns and calluses.
The most common area for the formation of calluses on the bottom of the foot is in the area of the ball of the foot. This is a weight bearing area where the long bones behind the toes called metatarsals, bear the greatest amount of weight and pressure. If one or more of these long bones (metatarsals) is out of alignment then excessive pressure is generated in the area producing a callous. The callused area can be very discreet and have a “core” or they can be more dispersed covering a larger area. These areas can become quite painful as the skin thickens. People who have diabetes are at risk of these areas breaking down producing sores or ulcerations that can become infected. People with diabetes should not try home remedies and should see a doctor for the treatment.
There are numerous over the counter treatments for corns and calluses. Some of these remedies have an acid in them that burn the callous off. Care should be taken when using these medications. If used incorrectly they can cause a chemical burn to the skin. Additionally these remedies are only temporary because the source of the pressure has not been alleviated. Professional treatment consists of using a special shoe insert called a functional orthotic that corrects foot function. In certain instances surgery may be recommended. Surgery is directed at correcting the alignment of the offending bone. Cutting out the callous will only make the condition worse if the underling boney problem is not corrected. Metatarsal surgery is discussed in another section.
Home treatment should be directed at reducing the pressure between the toes with cotton or a foam cushion and using an antibiotic ointment to reduce the risk of infection. Over the counter corn removers should never be used in this area because of the risk of increased damage to the skin resulting in infection. Professional treatment consists of removing the irregular shaped bone that causes the development of the corn. Some patients prefer that the doctor simply trim down and pad the calloused areas. This is a common form of treatment in patients with diabetes.