Corns and calluses are a thickening of the skin caused by pressure, friction, or shearing forces. They present as a thick hard area of skin and are often flaky and dry. Corns and calluses are terms that can be used interchangeably. Technically a corn is a smaller, deeper area of thick skin while a callus is usually a diffuse, flattened area of hard skin. Corns are common on the toes while calluses are found more commonly on the foot. Medically speaking, corns and calluses are a hyperkeratosis, which is an accumulation of the outer layer of the skin cells called keratinocytes. The cells build up as part of the body’s protective mechanism but ultimately become too thick and painful. The medical term for a corn is a heloma durum.
Corns can also develop between the toes. When this occurs, it is often white and soft. This type of corn is called a heloma molle. A common site for a heloma molle is between the 4th and 5th toes. There is usually pain between the toes that is worse with shoes. The callus between the toes must be removed because the thick callus will cause pressure were the toes meet.
Treatment for corns and calluses involves cutting the thick skin away with a scalpel. The process is painless because the callus is made up of dead skin cells. Treatment also includes alleviating the pressure causing the lesion.
This will prevent them from growing back. Alleviating the pressure may require changing shoes, stopping certain activities, applying corn pads, or surgery. There are also medications available for corns and calluses. These medications all have an ingredient that is a keratolytic, such as urea or salicylic acid. Keratolytics dissolve skin cells which allow the callus or corn to thin out. Care should be taken with this form of treatment as the medication often migrates after application and skin cells not involved in the callus are eaten away causing an ulcer to form.
Patients with other medical conditions such as diabetes or poor circulation should be especially cautious when they develop corns and calluses. In these patients the skin under the corn or callus can break down and become an ulcer. Many of the horror stories of diabetics losing their toes or feet begin with a simple corn or callus that is not treated. Any diabetic who develops a callus or corn should see a podiatrist immediately.
Your podiatrist will generally begin by trimming down the thick skin with a scalpel. Your podiatrist then may apply padding to off weight the area and recommend different shoe brands that will cause less pressure to the affected area.
Occasionally, depending on the specific cause, surgery may be necessary. If the callus is caused by a bone spur or other bony abnormality, such as a hammertoe, surgery may be required to address the underlying cause. Surgery is aimed at removing the spur or realigning the bones that are causing the excess pressure.