A condition characterized by a reticular or fishnet pattern on the skin of lower extremities and other parts of the body. This red and blue pattern is due to deoxygenated blood in unstable dermal blood vessels. The condition is intensified by cold exposure and relieved by rewarming.

A recurrent purple discoloration of the skin that does not blanche and is found in a lacy, network pattern, most often in the lower extremities. It may be aggravated by exposure to cold and is classified as idiopathic or secondary. Secondary livedo reticularis may be a cutaneous manifestation of immune system disorders (e.g., lupus erythematosus, rheumatoid arthritis, cryoglobulinemia, lymphoma, etc), and hematologic disorders (polycythemia vera).

Livedo reticularis is characterized by the presence of a bluish purple, mottled or netlike pattern in unbroken circles on the skin. Exposure to cold environments usually intensifies the vascular pattern. Presumably, the condition results from slow or stagnant blood flow, vessel-wall pathology, and decreased oxygen tension.