Red blood cells provide oxygen to body tissues. Most of the time, almost all red blood cells in the arteries carry a full supply of oxygen. These blood cells are bright red and the skin has a pinkish or red hue.
Blood that has lost its oxygen is dark bluish-red. People whose blood is low in oxygen tend to have a bluish color to their skin, called cyanosis.
Depending on the cause, cyanosis may develop suddenly, along with shortness of breath and other symptoms.
Cyanosis that is caused by long-term heart or lung problems may develop slowly. Symptoms may be present, but are often not severe.
When oxygen levels have dropped only a small amount, cyanosis may be hard to detect.
In dark-skinned people, cyanosis may be easier to see in the mucus membranes (lips, gums, around the eyes) and nails.
Cyanosis that is seen in only one part of the body may be due to:
A blood clot that blocks the blood supply to a leg, foot, hand, or arm
For shortness of breath and cyanosis, you may receive oxygen.
Kraft M. Approach to the patient with respiratory disease. In: Goldman L, Schafer AI, eds. Goldman’s Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 83.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.