Cyanosis
Disease Information
In-Depth
What is cyanosis?
Cyanosis is a bluish color in the skin, lips and nailbeds caused by a shortage of oxygen in the blood.
Why does cyanosis occur?
Cyanosis occurs because blood changes color in the presence (or absence) of oxygen. Red blood has enough oxygen whereas blood with decreased oxygen turns blue or purple. Red blood flowing through capillaries in the skin produces a healthy red-pink color. Blue blood causes a blue-purple tint to the skin.
What conditions cause cyanosis?
Cyanosis is usually caused by abnormalities of the heart, lungs or blood.
- lung abnormalities - can cause some blood to flow through them without collecting oxygen
- heart abnormalities - can cause some blood to bypass the lungs never collect oxygen
- blood abnormalities - can decrease its ability to absorb oxygen
Some of the defects or diseases that can cause cyanosis are:
