Reddish discoloration of exposed skin areas, called frost erythema, is an important criterion for the diagnosis of fatal hypothermia. In the present study, we used immunohistochemistry in a prospective trial to show that on the molecular level, the correlate of frost erythema is hemoglobin without hemorrhage. Furthermore, we compared routine histological and immunohistochemical features of frost erythema, hematoma and livor mortis and established some criteria for their histological differentiation.
