PSI Barbering Practice Exam 2026 – 400 Free Practice Questions to Pass the Exam

A callus is classified as a keratoma, which refers specifically to a thickened area of skin that develops in response to continuous pressure or friction. When the skin is subjected to repetitive stress, it undergoes a process called keratinization, where the outer layer of skin thickens to protect the underlying tissues from damage. This adaptation is a natural mechanism of the body aimed at preventing injury and discomfort.

Understanding this, a keratoma can present itself as a hardened area, often seen on the hands or feet, where the skin has gradually thickened due to that persistent pressure or friction. The term "keratoma" encompasses various forms of thickened skin, and a callus is essentially a benign example of this category.

The other options presented do not accurately reflect the nature of a callus. A fungus refers to a type of organism that can cause infections, while a wart is a benign growth caused by a viral infection and a verruca is a specific type of wart, typically on the foot. None of these options capture the essence of a callus as a protective, thickened area of skin resulting from mechanical pressure.