Livedo reticularishttps://en.wikipedia.org/wiki/Livedo_reticularis
Livedo reticularis is a common skin finding consisting of a mottled reticulated vascular pattern that appears as a lace-like purplish discoloration of the skin. It may be aggravated by exposure to cold, and occurs most often in the lower extremities. The discoloration is caused by reduction in blood flow through the arterioles that supply the cutaneous capillaries, resulting in deoxygenated blood showing as blue discoloration. This can be caused secondarily by hyperlipidemia, microvascular hematological or anemia states, nutritional deficiencies, hyper- and autoimmune diseases, and drugs/toxins.

  • Lesion due to severe infrarenal aortoiliac stenosis.
  • Erythema ab igne vs. Livedo reticularis
References Livedo reticularis: A review of the literature 26500860 
NIH
Livedo reticularis (LR) is a cutaneous physical sign characterized by transient or persistent, blotchy, reddish-blue to purple, net-like cyanotic pattern. LR is a benign disorder affecting mainly middle-aged females, whereas livedo racemosa (LRC) is pathologic, commonly associated with antiphospholipid antibody syndrome.