Cranial means brain. If someone has cranial vasculitis, i would assume that the brain is involved suggested a severe illness and requires urgent treatment. Some patients may have mild vasculitis which may just affect the skin and overall is mild. Again, what organs are affected will dictate how severe and different the vasculitis is.
Vasculitis. Vasculitis is generally classified by which type of blood vessels are showing damage from the autoimmune reaction. Any organ system can be involved. The same type of immune reaction can cause generalized vasculitis or intra-cranial vasculitis. Why certain organ systems are attacked while others are spared is likely due to the cell-specific antigen target of the immune reaction.