Elephant skin would be consistent with long term irritation leading to lichenification of the skin which causes hair loss and the elephant skin appearance; the irritation may be caused by allergies, parasites, infections (particularly Malassezia dermatitis) or endocrine disorders. (wagwalking.com)
The white arrow points to mild hair loss, hyperpigmentation, and lichenification in a Yorkie. (lbah.com)
Chronic changes to the skin can occur, especially lichenification and hyperpigmentation. (lbah.com)