A transient livid mottling of the extremities, less often of the trunk, on exposure to a moderate degree of cold, is so common, especially among children, as to be considered almost physiologic.
This so-called livedo e frigore, or cutis marmorata, is believed by some1 to be due to a passive congestion in part of the peripheral capillary circulation. According to Unna, the islands of normal color are the bases of inverted cones, the apexes of which are the nutrient arteries of the cutis. The livid bands lie along the lines of intersection of these cones. The capillary circulation here is entirely collateral, and the pressure is at a minimum.
In persons who are subject to cutis marmorata, Unna assumes an increased tonus of the muscles in the walls of the veins. When the skin is chilled in these persons, there is a reflex spasm of the nutrient arteries and