Q. Why is there no cyanosis in severe anaemia?
Doctor Answer is medically reviewed by SecondMedic medical review team.
Cyanosis is the bluish or purplish discoloration of the skin and mucous membranes that occurs when there's not enough oxygen in the blood to turn it red. In severe anaemia, a person's red blood cell count has dropped significantly, leading to insufficient oxygen-carrying capacity. As such, even if there was cyanosis present, it may be difficult for a doctor or clinician to detect as the individual’s overall reduced red blood cell count would keep any cyanotic areas from standing out against non-cyanotic ones. On top of this physiological barrier, typical causes of cyanosis are also absent in anemic patients due to their low iron levels; these include hypoventilation and right side heart failure (the body’s white cells can't take up iron molecules).
That being said, while individuals with severe anaemia may not exhibit physical signs of cyanosis as outwardly visible on their skin or mucous membranes due to lower hemoglobin counts compared with those without anemia, superficial tissues can still appear pale - at least more than normal - which can be linked with an insufficient amount of circulating hemoglobin (and therefore oxygen) throughout the body.