Corns and calluses
Corns and calluses are common skin lesions in which there is a localised area of thickened skin. A corn (clavus, heloma) is inflamed and painful. They are known as ‘soft corns’ (heloma molle) if the surface skin is damp and peeling, for example between toes that are squashed together. A callus (tyloma) is an area of painless hard skin.
What causes corns and calluses?
Corns and calluses are caused by response to friction and pressure. Repetitive injury results in the skin trying to protect itself from blistering. The basal epidermal cells (keratinocytes) increase in number resulting in thicker prickle cell layer and thicker stratum corneum on the skin surface.
The most common sites are on the hands and feet, but any area of skin may be affected. Examples include:
- On the palms, from holding a racquet or hammer
- On the knuckles from pushing oneself out of a wheelchair
- On the side of the foot, from tight shoes
- On the ball of the foot, from running barefoot
Thick skin on the entire palm or sole is known as palmar or plantar keratoderma. This term is also used for genetic disorders in which there are multiple areas of callus (punctate keratoderma).
What is the treatment for corns & calluses?
The important thing is to relieve the pressure on the affected area of skin.
- Choose well-fitting, comfortable, flat footwear
- Use leather gloves for repetitive tasks that injure the skin
- Apply a protective corn plaster or cushion to apply pressure more evenly around the affected area to reduce friction
- Separate toes using soft cotton, lamb's wool, moleskin or web spacers to relieve pressure
- Special orthotics may be made to measure
Reduce skin thickness.
- Sandpaper, file or pumice the surface (this is easier when the skin has been soaked in warm water for 10 minutes or longer)
- Pare down the surface using a specially designed corn trimmer to remove the central core
- Apply keratolytic creams or heel balms containing urea, salicylic acid or lactic acid
To ease the discomfort of painful cracks (fissures):
- Apply a thick, lubricating ointment such as petroleum jelly
- Seal the surface with adhesive such as Liquid Bandage™ or nail glue
- Use antbiotic ointment in case of infection
- Cover with a thick adhesive plaster
It may be helpful to visit a podiatrist for treatment of calluses and corns on the feet.
Sometimes protruding bone has to be surgically removed by an orthopaedic surgeon, for example bunion repair.
On DermNet NZ:
- Corns – Medscape Reference
- Corns & calluses overview – Medscape Reference
- Patient information: Corns and calluses (The Basics) – UpToDate (for subscribers)
Books about skin diseases:
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