Vasculitis , a group of diseases featuring inflammation of the wall of blood vessels including veins , arteries and capillaries due to leukocyte migration and resultant damage. While most vasculitides are rare, they generally affect several organ systems and can cause severe disability. Vasculitides can be classified by the size of the blood vessel that they predominantly affect. Takayasu arteritis. Primarily affects the aorta and its main branches. At least...