Cyanosis

Cyanosis is the blue coloration of body parts such as lips, fingertips, skin and mucous membranes. It is caused by a reduction in the partial pressure of oxygen in the blood. Little oxygen makes the blood look almost dark red to blue, so that the peripheral parts of the body, which are heavily supplied with blood vessels, take on a kind of blue to violet colour. The reason for the low oxygen saturation of the blood can lie in heart or lung problems. Poisoning can also cause cyanosis.