Hyperkeritosis - Callus formation

Question 1

What is Callus?

Answer 1

A diffuse area of hyperkeratosis

Callus forms where there are atypical forces, or where the physiological resistance of the skin has been exceeded

Question 2

What is Physiological Callus?

Answer 2

Symtom-free callus - callus forms as an inflammatory response, and is a normal process to protect the foot from trauma

Question 3

What is Pathological Callus?

Answer 3

This is where the callus formation is painful, and is a result of:

• Abnormal foot mechanics
• Foot deformities
• dermatological conditions

This causes a defect in keritinisation

Question 4

What is the Etiology of callus?

Answer 4

• Intermittent compression / shearing
• Intrinsic factors - bony prominences, obesity, systemic diseases
• Extrinsic factors - poor/ill fitting footwear, high level of physical activity

Question 5

What is the process in which callus is formed?

Answer 5

1. Excessive pressure placed upon skin
2. Inflammatory response is triggered, causing increased keratinocyte mitosis
3. Keratinocytes release cytokins which further increase keratinocyte proliferation
4. This causes hyperkeratosis of the Stratum Corneum
5. the thickened callus means stratum corneum is less able to dissipate mechanical stress, which in turn irritates keratinocytes to release inflammatory mediators and the inflammatory response reoccurs
6. positive feedback loop

Question 6

Why does desquamation decrease with hyperkeratosis?

Answer 6

Rapid keratinocyte production means keratinocytes reaching the stratum corneum are immature, and desmosomes between the keratinocytes have not fully broken down

Question 7

How are callus usually treated?

Answer 7

Sharp Scalpel Debridement

Question 8

What other treatments are used for callus?

Answer 8

• Strapping and padding
• Orthotics to redistribute pressure
• Footwear appraisal
• Patient education - emolient use, pumice stone