Final answer:
Superficial plexus disease in vasculitis is characterized by inflammation of superficial blood vessels.
Step-by-step explanation:
The characteristic of superficial plexus disease in vasculitis is inflammation of superficial blood vessels. Vasculitis refers to the inflammation of blood vessels, and in this case, it specifically affects the superficial blood vessels. This inflammation can cause the blood vessels to become damaged and rupture, leading to the formation of small red or purple spots called petechiae on the skin.