- Leonine facies is a classic feature of lepromatous leprosy, caused by widespread infiltration of the skin and soft tissues on the face by Mycobacterium leprae.
- This leads to thickened, nodular, and leonine (lion-like) facial appearance.
- In contrast, hypopigmented anesthetic patches and single thickened nerves are more typical of tuberculoid leprosy.
- Ulceration of the nasal septum can occur but is less characteristic and not a hallmark feature.

Reference: Harrison's Principles of Internal Medicine, 20th Edition, Infectious Diseases/Leprosy