Certain elements are recognized as the source of the pathology: Abnormal functioning of blood vessels This dysfunction causes stagnation of blood in the vessels of the face which leads to dilation of the vessels, even edema and alteration of the endothelium (membrane which covers the inside of the veins of the face)
doi: 10.1186/s12958-018-0343-0 105 NogueiraBGPereiraRRBitencourtJLMilanBReisWVAJuniorMVet al
George JN
Lenzi A, Lombardo F, Sgro P, Salacone P, Caponecchia L, Dondero F, Gandini L
Briefly, whole blood (600 l) was immediately mixed with 2x volume of ice-cold 1.7 M perchloric acid solution to prevent the spontaneous formation of acetaldehyde
--- (2018b) The Debut of the China Clipper. In Teresa Webber and Jamie Dodson (eds.) Hunting the Wind: Pan American World Airways Epic Flying Boat Era, 1929-1946, pp