Callosity

Callositas (plural: callositates; colloquially often referred to as "callus") describes a circumscribed thickening of the uppermost layer of the skin (stratum corneum) caused by chronic mechanical stimuli such as friction or pressure.

Causes and development

Pressure and friction:
- Tight shoes, incorrect footwear or occupational activities (e.g. working with tools) can lead to increased callus formation.
Physical adaptation reaction:
- The skin forms more horny cells (keratinocytes) for self-protection in order to protect the underlying tissue from further stress.
Predisposition or underlying diseases:
- Some people are genetically prone to severe callus formation.
- Certain diseases (e.g. diabetes mellitus) can increase the risk of foot problems, as pressure sores are often noticed later.

Typical localizations

Feet (especially heels, balls of the feet, toes)
Hands (for manual work, sports, playing instruments)

Treatment and care

Mechanical removal:
- Removal of the callus using pumice stone, callus files or in medical foot care (podiatry).
Care products:
- Callus-reducing creams and ointments (often with urea) soften the skin.
Prophylaxis:
- Wear suitable shoes, reduce pressure points with insoles or pads.
- With heavy use (e.g. sport), ensure well-fitting shoes and regular foot care.

Differentiation from similar skin thickenings

Clavus (corn): This is a keratinized cone that penetrates deep into the skin and can cause painful pressure points.
Hyperkeratosis: Generally increased keratinization, which can have many causes (including psoriasis, ichthyosis).

Conclusion: Callositas is a natural protective reaction of the body to recurring pressure and friction, but can cause discomfort if excessive. Regular care and, if necessary, professional help (podiatrist, doctor) are advisable to avoid complications.