Cyanosis

Cyanosis is a medical symptom characterized by a bluish discoloration of the skin and mucous membranes, due to a lack of oxygen in the blood. It is most commonly seen around the lips, fingers, and toes, and can range in severity from mild to life-threatening. Early signs may include a faint bluish tinge to the skin, but as the condition progresses, the skin and mucous membranes may become a deep blue or purple. Cyanosis can develop suddenly or gradually, and is most often caused by a respiratory or cardiovascular condition.