Necrobiosis lipoidica diabeticorum (NLD) is a rare skin condition in which lesions normally develop on the lower part of the legs. Other body parts can be affected, though.

NLD occurs due to collagen degeneration and inflammation associated with the thickening of blood vessel walls and fat disposition.

A rash of several spots usually appears as raised patches that are shiny red-brown in colour. These spots may develop into open sores which can be slow to heal.