Last reviewed 01/2018

In the acute stage, thrombosis occurs in small and medium sized arteries and veins. Unlike arteriosclerosis, digital vessels are commonly involved. Dense aggregates of polymononuclear leukocytes are seen within the thrombus. There is no necrosis of the arterial wall unlike in arteriosclerosis or polyarteritis nodosa. Later, microabscesses are observed and giant cells appear within the granulation tissue. The thrombus is organised and its lumen may be re-canalised.

Older lesions show chronic inflammatory infiltrates or extensive fibrosis. Peripheral nerves may be involved in addition to arteries and veins.