Blue discoloration of the skin and mucous membranes is called?

• A. Pallor
• B. Cyanosis
• C. Mottling
• D. Acrocyanosis

Answer: (B)

Cyanosis is the blue discoloration of the skin and mucous membranes caused by increased deoxygenated hemoglobin in arterial blood, signaling that oxygen delivery to tissues is insufficient. When this bluish tint appears on the lips, tongue, and other mucous membranes, it points to central cyanosis and true hypoxemia from conditions like lung disease, congenital heart disease, or severe systemic illness. Peripheral cyanosis, by contrast, shows bluish coloring mainly in the extremities due to slowed blood flow and may occur without systemic hypoxemia. The other terms describe different patterns: pallor is pale skin from anemia or vasoconstriction; mottling is a patchy, marbled skin appearance from variable perfusion; acrocyanosis is a benign, often temporary blue appearance of the hands and feet in newborns due to immature circulation.