why is nurse ratchets face contiuously being described with the color red?

Red has a lot of symbols here. Certainly Ratched is angry much of the time which paints her that red complexion. Half the time she looks like she is going to blow up any second. There is also a sense of sexuality to her. Ratched tries really hard to conceal the fact that she is a woman. Femininity makes her feel vulnerable. Her rather large bosom betrays her though. This together with the red on her face do not go unnoticed by the men.