VASCULITIS

Ulcers caused by a district microcirculation inflammatory insufficiency, mainly sustained by autoimmune reactions in several different medical conditions (infections, cancer) or syndromes or as a reaction to certain drugs.
The process involves vessels of different calibers and it manifests itself with skin lesions of different types (petechiae, nodules, plaques) until it determines skin ulceration, with frequent involvement of lower extremities. 
Microscopically, the vascular lumen obstruction from….. is typical, with resulting necrosis.
Macroscopically, they can involve a single district (e.g., skin or kidney), but, more often, they follow a general trend and affect multiple organs.
Some Authors (V. Falanga: “Cutaneous Wound Healing”; M. Romanelli: “Atlante di ulcere cutanee”) define them as inflammatory and they group them with ulcers like those due to Pyoderma Gangrenosum and those due to connective tissue alterations (rheumatoid arthritis, systemic lupus erythematosus, scleroderma).