[Livedo reticularis: dermatologic alarm signal in cold agglutinin disease].

A hitherto healthy adult man developed paroxysmal cold agglutinin disease following an infection of the upper respiratory tract with mycoplasma pneumoniae. Despite continuous blood exchange he died of massive intravascular hemolysis and uremia after 5 days. A presenting striking symptom of this rapidly fatal disease was the acute onset of generalized livedo reticularis. The disease was caused by the rare anti Pr-cold agglutinins which are capable of eliciting hemolysis even in low titers and, in the present case, at body temperature.