Corns

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Causes of corns

Corns are a painful type of callus which appear on the foot. Unlike a callus, a corn is separate from the surrounding area of skin. There are two common types of corn: hard corns and soft corns.

• Hard corns – this is the most common type and is a concentrated area of dry skin that often occurs on the toes.
• Soft corns – this type of corn is more painful and develops mainly between the toes. Soft corns are caused by exposure to moisture and can become infected by bacteria or fungi.

Other less common types of corn include:

• Seed corns – painless clusters of corns that appear on the sole of the foot
• Vascular corns – corns that appear on blood vessels and which bleed if cut
• Fibrous corns – chronic corns that attach to deep layers of skin

Corns occur due to constant pressure on the bony areas of the feet. This can be due to a number of reasons, the most common of which include:

• Badly fitted footwear – shoes that are too tight, too small or have irregular shaped soles (e.g. high heels) commonly cause corns.
• Sport and exercise – people who exercise regularly such as athletes are prone to corns due to excessive pressure being placed on the foot.
• Foot abnormalities – feet or toes that have developed abnormally can press against shoes causing corns.
• Broken toes or bones in the foot – a fracture can set a bone out of place causing the foot to press against the shoes.

Symptoms of corns

Corns are typically regular in shape and can appear grey, white or yellow in colour. They usually form on the outside of the first or fifth toes but can form anywhere on the bony areas of the foot. Soft corns form between the toes.

If you have corns, pain is usually experienced when walking or wearing shoes.

Diagnosis of corns

If you are experiencing persistent foot pain visit your GP and they will examine your foot for signs of corns. They may ask about the type of shoes you regularly wear and if you've had any previous surgery on your feet.

Corns can be mistaken for verrucas and the GP may remove the top layer of skin to check for blood vessels which would be present with a verruca.

If your problem is severe, you may be referred to a podiatrist who will check for any foot abnormalities. If a problem with the foot's structure is suspected then you may require an X-ray to see if this the cause of your corns. You may also need a foot pressure pattern test, known as a 'pedobarograph'.

Related terms

Hyperkeratosis

Calluses

Blisters

Verrucas

Hammertoes

Plantar warts

Tyloma

Skin ulceration

Pumice stone