Takayasu's Aeritis : does not involve the peripheral limb vessels. Its an inflammatory and stenotic disease of medium and large-sized aeries characterized by a strong predilection for the aoic arch and its branches (thus also k/an aoic arch syndrome) Giant cell aeritis: also, k/a cranial aeritis or temporal aeritis is a systemic chronic inflammatory vascular disease with many characteristics similar to Takayasu disease involves medium and large-sized aeries, characteristically one or more branches of the carotid aery, paicularly the temporal aery. Hypersensitivity angiitis hypersensitivity angiitis also k/a cutaneous vasculitis or leukocytoclastic vasculitis typically involves the small vessels of the skin. Postcapillary venules are most commonly involved vessels; capillaries and aerioles are involved less frequently. its the most commonly encountered vasculitis in clinical practice. the hallmark of idiopathic cutaneous vasculitis is the predominance of skin involvement. Skin lesions typically are palpable purpura.