[答]“三红”、“三病”是流行性出血热早期症状和体征的一部分,具有一定的特征。要解释为什么出现,必须从其发病机制谈起。虽然流行性出血热的发病机制尚不太清楚,但从其发病和病理改变上看,血管损害是极明显的。由于出血热病毒及其毒素作用于全身小血管和毛细血管,首先引起广泛的血管扩张、麻痹和瘀血,而面、颈、上胸部皮肤 [A] “three red ”, “three disease ” is part of the early symptoms and signs of epidemic hemorrhagic fever, has certain characteristics. To explain why it arises, we must talk about its pathogenesis. Although the pathogenesis of epidemic hemorrhagic fever is not yet clear, its pathological changes and blood vessels damage is very obvious. Due to hemorrhagic fever virus and its toxins acting on the body’s small blood vessels and capillaries, first of all cause a wide range of vasodilation, paralysis and blood stasis, while the face, neck, upper chest skin