What is the term for a surface that has become hardened and rough, similar to leather?

The term that describes a surface that has become hardened and rough, resembling leather, is lichenification. This process often results from repeated scratching or irritation of the skin, leading to thickened and leathery patches. Lichenification reflects a chronic condition where the skin undergoes changes due to constant trauma or inflammation, making it look and feel different from normal skin.

Fissures represent small cracks or splits in the skin, often not associated with the generalized thickening and hardness that lichenification entails. Keloids are a type of raised scar that forms due to an overproduction of collagen and do not necessarily involve a rough texture similar to leather. Crust generally refers to dried exudate on the skin's surface, such as scabs formed after wounds or lesions, which lacks the thickened consistency characteristic of lichenification.