Corns and calluses are one of the most common foot conditions. Corns and calluses are a thickening of the outer layer of skin, which occurs in response to friction or pressure on the foot. This thickening is known medically as hyperkeratosis.
A small corn or callus may not cause any symptoms. However a large, bulky corn or callus can cause foot pain and difficulty walking.
With prolonged irritation, a discoloured area (brown, red or black) may develop under a large corn or callus. This discoloration is caused by a small amount of bleeding in the space between thick and normal skin. In severe cases, the thick and normal skin may separate, exposing the area to possible infection, especially in people with diabetes.
Corns are usually hard and circular, with a waxy or translucent centre. At the centre of a corn is often a very dense knot of skin called a core, which is located over the area of greatest friction or pressure. Corns may become painful or ulcerated in response to persistent friction.
Firm, dry corns that form on the upper surfaces of the toes are called hard corns. Pliable, moist corns that form between the toes are called soft corns.
Unlike a corn, the thickening in a callus is evenly distributed. There is no dense central core. Calluses usually occur on the soles of the feet, however they can also form on other parts of the body that are exposed to long-term friction. For example, calluses are often found on the hands of manual labourers and guitar players.
On the soles of the feet, calluses typically develop near the base of the toes, where there may be friction from the inside of shoes. Less often, calluses are related to walking problems or foot abnormalities that place unusual stresses on parts of the foot during walking.
What causes corns and calluses?
Corns and calluses develop as part of the skin’s normal defence against friction and pressure on the foot. This friction or pressure can be caused by:
- Footwear which causes rubbing or pressure on part of the foot. For example, narrow, tight or ill-fitting shoes.
- Other conditions which may alter the mechanics of the foot, placing excessive pressure on certain areas of the foot. For example, people with feet that roll inwards (flat feet), may experience increased pressure on the ball of the foot beneath the big toe, and the inside of the heel. A podiatry assessment will identify any abnormalities that may need correction in order to relieve excess pressure/friction on the foot.
- Previous surgery or trauma can alter structural alignment of the foot, causing excessive pressure on certain part of the foot.
- Bony prominences on the foot (such as those caused by bunions, hammertoe or arthritis) may be more prone to rubbing/friction.
How are corns and calluses treated?
In most cases, corns and calluses are simple to treat and respond well to conservative care. Following assessment, treatment options may include:
- Shaving away some of the thickened skin to relieve pain and pressure in the affected area. Depending on the situation, regular examination and removal of corns and calluses may be necessary.
Never try to shave or cut a corn or callus on your own, especially if you have diabetes or poor circulation. This procedure should always be performed by a podiatrist, in order to prevent damage to healthy tissues which can result in infection and scarring.
- Advice on appropriate footwear and foot care.
- Modifying footwear or using silicon protectors/pads to relieve pressure on the affected area.
- Inserts (orthotics) may be recommended to redistribute the forces that cause friction and pressure inside your shoes. This helps to relieve the stress on your feet when you walk.
In rare cases, foot surgery may be necessary to treat corns and calluses that are not relieved by conservative care options.