Livedo reticularis.

A wide variety of internal diseases may be associated with livedo reticularis. In adults, the most frequently encountered associated diseases are characterized by vessel wall disease or intravascular obstruction. In the former group, lupus erythematosus is particularly important, since LR along with anticardiolipin antibodies appears to be a marker of serious cerebrovascular and renal disease. Appropriate evaluation of patients presenting with LR includes a careful history and physical examination. Laboratory studies, including a complete blood count, platelets, coagulation profile, cryoproteins, antinuclear antibodies, and anticardiolipin antibodies, are useful screening tools for the important associated diseases. Table 1 summarizes the spectrum of entities associated with LR and points up the challenge of evaluating this distinctive cutaneous finding.