[Livedo reticular: classification, causes and differential diagnoses].

Livedo reticularis (LR) is a common finding and results from a physiological vasospastic response to cold or systemic disease, characterized by a pattern of cyanotic discoloration, or erythematous-cyanotic aspect. LR can be congenital or acquired. Among the acquired LR stand out from the physiological or cutis marmorata, the idiopathic, the induced vasospastic, those due to intravascular diseases or even in the wall of the vessels. This article reviews several clinical features, differential diagnosis and various causes of livedo.