Lack of oxygen in the blood causes a bluish discoloration in the skin or mucous membranes called cyanosis. Most cyanosis is seen as a result of congenital heart disease, pulmonary disease, or as a terminal event as in cardiopulmonary arrest.
Update Date 6/22/2015
Updated by: Denis Hadjiliadis, MD, MHS, Associate Professor of Medicine, Pulmonary, Allergy, and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.