What is a sign of cyanosis in lighter skin tones?

A sign of cyanosis in lighter skin tones is indeed indicated by a blue or purplish hue observed under the fingernails or around the lips. Cyanosis occurs when there is a lack of oxygen in the blood, leading to a noticeable change in color in areas where blood vessels are close to the surface of the skin. This bluish tint indicates that the tissues are not receiving enough oxygen and can be a critical signal of respiratory or cardiovascular problems.

Other choices, such as unusual warmth of the skin, yellowing of the eyes, or excessive sweating, correspond to different physiological conditions that do not specifically indicate cyanosis. Unusual warmth may suggest inflammation or infection, yellowing of the eyes is typically associated with liver issues (jaundice), and excessive sweating can indicate stress or various other medical conditions, but none of these indicators reflect the marked lack of oxygen that cyanosis signifies. Thus, recognizing the bluish color is essential for assessing the severity of oxygen deprivation in light-skinned individuals.