The necrotic epithelium becomes embedded in exuding fibrin and red and white cells，so that a grayish pseudomembrane is formed-commonly over the tonsils，pharynx or larynx.

坏死的上皮被纤维蛋白、红白一起形成灰白色的假膜，通常覆盖扁桃腺、咽或喉。