"Vasculitis is inflammation of the blood vessels resulting in damaged vessels leading to potential complication such as tissue ischaemia from lumen narrowing or from thromboembolic events from platelet consumption during vessel repair. Vasculitis classically refers to arteries rather than veins. Vasculitis can be primary or secondary. Primary being its own disease and secondary being secondary to a drug, disease or cancer. Primary vasculitides are classified into the size of the blood vessels affected; large vessel vasculitis such as those disease affecting the aorta and its main branches, medium vessel vasculitis such as those affecting branches of the kidneys and small vessel vasculitis which affect the arterioles and capillaries. The medium and particularly the small vessel vasculitis are the type which present with cutaneous, skin findings such as purpura and petechiae because the smaller blood vessels are more superficial. The pathophysiology of vasculitis is unclear, but is thought to be primarily immune mediated. Because there are different types of vasculitis the pathological findings and therefore the pathophysiology would be slightly different."