The first skin changes in<unk>  lesions are mottling of the skin and induration in a livedo reticularis pattern. As tissue thrombosis and infarction occurs, a black, leathery eschar in an ulcer with adherent black slough develops. Surrounding the ulcers is usually a plate-like area of indurated skin. These lesions are always extremely painful and most often occur on the lower extremities, abdomen, buttocks, and penis. Lesions are also commonly multiple and bilateral. Because the tissue has infarcted, wound healing seldom occurs, and ulcers are more likely to become secondarily infected. Many cases of<unk>  lead to systemic bacterial infection and death.<unk>  is characterized by the following histologic findings: # systemic medial calcification of the arteries, i.e. calcification of tunica media. Unlike other forms of vascular calcifications (e.g., intimal, medial, valvular),<unk>  is characterized also by # small vessel mural calcification with or without endovascular fibrosis, extravascular calcification and vascular thrombosis, leading to tissue ischemia (including skin ischemia and, hence, skin necrosis). Heart of stone=== Severe forms of<unk>  may cause diastolic heart failure from cardiac calcification, called heart of stone. Widespread intravascular calcification typical of<unk>  lesions occur in the myocardium and prevent normal diastolic filling of the ventricles.
Calciphylaxis
Tachyphylaxis
Purpura fulminans
Acne fulminans
Tetanus
Phlebothrombosis
Papular purpuric gloves and socks syndrome
Visceral larva migrans