In the past, there has been some debate about whether this was just a particularly aggressive form of atherosclerosis, but there are numerous differences. Second, the primary involvement appears to be of medium-sized arteries, rather than the larger vessels of atherosclerosis. Like many of the other arteritides Buerger's disease has a segmental distribution. It often involves the upper limbs as well as the lower limbs, and may lead to progressive peripheral gangrene and repeated amputations. The association with cigarette smoking is nearly absolute.
Classic cases involve the kidneys, the lungs, and often the upper airway.
A limited form of Wegener's also exists, which is restricted to the upper airway, and may present as chronic necrotizing inflammation of the mucosa of the nasal cavity and sinuses. In many patients with hypersensitivity vasculitis, there is evidence of an associated disease process. Some patients with hypersensitivity vasculitis develop it secondary to a neoplasm, whereas others may have SLE or rheumatoid arthritis. A common factor in these cases is believed to be formation of immune complexes which lodge in the vessel wall, with secondary activation of inflammatory mechanisms. This again leads to immune complex deposition.