Calluses, corns and blisters on the feet: how to tell them apart and prevent them

In short: a callus is a patch of hard skin with no clear borders, a corn has a defined shape, and a blister is a fluid-filled bubble caused by friction. All three usually come from pressure and friction in badly fitting shoes. Calluses and corns without a core can be softened and smoothed at home or in a salon. A core corn, which hurts sharply under pressure, needs a podiatrist.

Callus, corn or blister: how to tell them apart

• Callus — hard, often yellowish skin that has lost its elasticity, with no clear borders or defined shape. It may hurt or burn when you walk. Most common on heels, balls of the feet and toes.
• Corn — thickened skin with a defined shape. Often painless at first, it can later hurt under pressure. The surface may flake or crack.
• Core corn — dense, with a distinct centre, and goes deep into the skin. The core can press on nerve endings, causing sharp pain when walking or under pressure.
• Blister — a bubble filled with fluid, caused by friction. In narrow shoes it often appears on the big toe and the little toe.

What causes them

Calluses and corns are the skin's protective reaction to pressure and friction. The epidermis cells divide faster and the skin thickens to protect the deeper tissues. The most common causes:

• Uncomfortable shoes — tight, stiff, high-heeled or poorly fitting.
• Standing for long periods, especially on hard surfaces.
• Excess weight — more load on the feet, especially the heels.
• Flat feet and foot deformities, such as bunions — pressure is spread unevenly.
• Dry skin and too little care.
• Other factors: age, vitamin deficiencies and conditions that change the position of the foot bones.

Blisters are mainly caused by friction. In synthetic shoes that do not breathe, the skin gets hot and sweaty, and blisters can appear even between the toes.

Caring for calluses and corns without a core

Soften first, then smooth:

1. Soften the skin in a warm foot bath; you can add sea salt. Or use the Soft Blade SPA bath with 15% urea: for a pedicure 3–10 pumps, 7–15 minutes.
2. For thicker hard skin, use a keratolytic with urea, e.g. the Soft Blade keratolytic gel (38% urea): apply it to dry skin, then soak your feet in water for 5–10 minutes. No more than once a week.
3. Gently smooth the foot with a pumice stone or a foot file. Do not overdo it.
4. Neutralise and moisturise. Use the Universal Neutralizer, which stops the keratolytic from working and restores a neutral pH, then apply a moisturising cream.

Repeat regularly. Never cut calluses or corns with a blade — it is easy to injure yourself.

In a salon, hard skin is removed with an e-file (machine pedicure), keratolytics and professional peels.

Blisters: what not to do

Do not pop or cut a blister: once it bursts, it leaves an open wound. Instead, remove the cause, which is friction: wear shoes in the right size and socks made of natural fabrics, so the skin does not get hot and sweaty.

How to prevent calluses, corns and blisters

• Well-fitting shoes — the right size, suited to the season, with a comfortable heel height. High heels with a pointed toe are not the best choice for everyday wear.
• Natural materials — for shoes, and cotton or wool for socks and tights.
• Orthopaedic insoles for flat feet or other deformities.
• Washing and moisturising. Apply a foot cream regularly, e.g. the softening foot cream with 5% urea for dry, rough and cracked skin. It reduces the look of calluses.
• Regular pedicures that remove hard skin.
• Act early. At the first signs of roughness, reach for a keratolytic. For dry, rough skin with calluses, try the restorative foot balm with salicylic acid: it gently exfoliates, reduces the thickness of hard skin and helps prevent cracks.

When to see a specialist

See a podiatrist or a dermatologist if:

• you have a core corn — do not try to remove it yourself;
• you have pain, deep cracks, redness or swelling;
• you have a chronic condition such as diabetes — then even minor skin damage can have serious consequences.

FAQ

How do I tell a callus from a corn?

A callus has no clear borders or shape; a corn has a defined shape. A corn with a dense centre that causes sharp pain under pressure is a core corn — see a podiatrist.

Can I pop a blister?

No. When a blister bursts, an open wound remains. Remove the cause of the friction instead: well-fitting shoes and socks made of natural fabrics.

What happens if I do not take care of calluses?

Neglected hard skin, especially on the heels, can crack over time. Remove it regularly and moisturise; if cracks are deep or painful, see a podiatrist or a dermatologist.

See also: Cracked heels and hard skin: how to remove them step by step.