Idiopathic livedo reticularis* may occasionally be associated with ulcerations, especially of the lower extremities, occurring during the winter months.† It has been assumed that in idiopathic livedo reticularis the effect of cold on the blood vessels of the skin accounted for the predominance of the symptoms and the occurrence of ulcerations during the fall and winter months. The purpose of this article is to define a new syndrome associated with idiopathic livedo reticularis in which the ulcerations occur only or predominantly during the warmer months of the year. DEFINITIONS We would define "livedo reticularis" as a condition of the skin characterized by a reddish-blue, mottled, reticular or blotchy discoloration. It persists with a variation of degree regardless of the skin temperature, and has also been described as a marbling or a fish-net discoloration. Synonyms in the medical literature for this condition have been "generalized telangiectasia," ‡ "livedo racemosa," "livedo