Final answer:
Cyanosis is the term for the blue discoloration of the skin caused by a decrease in oxygenation of the blood.
Step-by-step explanation:
The blue discoloration of the skin is called cyanosis.
Cyanosis occurs when there is a decrease in the oxygenation of the blood. It can be caused by conditions that restrict the oxygen supply, such as asthma or a heart attack. The skin appears blue because of the dominant presence of dark red deoxyhemoglobin in the blood. Cyanosis is not related to the skin's pigmentation but rather a sign of reduced oxygen levels in the body.